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This study investigated the physiological responses of four distinct Faba bean (Vicia faba L.) genotypes, Seville (SEV), Aguadulce (AGUA), Tunisian (TUN), and F7, when subjected to phosphorus deficiency, with a particular focus on their responses in terms of growth, chlorophyll pigments, photosynthetic activity, and nutrient efficiency. The results revealed that growing Faba bean in a phosphorus-deficient environment induced a reduction in the plant growth, net photosynthesis, SPAD index, and tissue phosphorus content. Genotypic variations were observed, with TUN demonstrating relative tolerance as compared to the other genotypes, by exhibiting a higher capacity for phosphorus uptake under deficiency conditions, lesser phosphorus deficiency stress index (PDSI), higher phosphorus tolerance index (PDTI), and better phosphorus use efficiency (PUE). The latter are two physiological traits that discriminate the studied genotypes. They can be used for further screening programs. Our research contributes to a broader understanding of how Faba bean plants react to phosphorus deficiency, shedding light on the genetic variations. [ABSTRACT FROM AUTHOR]

Ocean acidification and warming caused by elevated CO2 are urgent problems facing the marine ecological environment. With the strengthening of environmental governance in China, anthropogenic inputs of terrestrial phosphorus into the coastal ocean have drastically decreased, resulting in frequent phosphorus deficiency in seawater. These environmental factors in the future may affect algal growth, photosynthesis and yield. As an important economic macroalga suitable for large-scale cultivation, Gracilariopsis lemaneiformis is also potentially affected by the coupling of ocean acidification, warming and phosphorus deficiency. In this study, G. lemaneiformis was cultured outdoors under two pCO2 levels (LC, 400 μatm; HC, 1000 μatm), two temperatures (LT, 20 ℃; HT, 24 ℃) and two phosphorus concentrations (LP, 0.1 μmol L−1; HP, 10 μmol L−1) to investigate its growth and photosynthetic performance. The results showed that LP significantly decreased the relative growth rates (RGR) and the maximum photosynthesis rate (Pm) of G. lemaneiformis both under LC and HC conditions. Under P depletion condition, the effects of warming and ocean acidification on the growth and photosynthetic performance of G. lemaneiformis showed an opposite trend, that is, HC caused a decrease in the growth, Pm, maximum relative electron transfer rate (rETRmax) and light utilization efficiency (α) from the rapid light response curve of G. lemaneiformis, and HT improved these parameters. Under LP condition, HC significantly inhibited the RGR of G. lemaneiformis in the LT group but had no significant effect on RGR in the HT group. Additionally, under LP condition, HC insignificantly affected PE and PC contents in the LT group, but significantly reduced these contents in the HT group. These findings suggest that phosphorus deficiency results in a decline in the growth of G. lemaneiformis and, under LP condition, the inhibition effect of ocean acidification on the growth of G. lemaneiformis could be mitigated by warming. This study provides scientific guidance for the field cultivation and selective breeding of G. lemaneiformis in phosphorus-deficient seawater under global climate change. [ABSTRACT FROM AUTHOR]

Phosphorus, a crucial macronutrient essential for plant growth and development. Due to widespread phosphorus deficiency in soils, phosphorus deficiency stress has become one of the major abiotic stresses that plants encounter. Despite the evolution of adaptive mechanisms in plants to address phosphorus deficiency, the specific strategies employed by species such as Epimedium pubescens remain elusive. Therefore, this study observed the changes in the growth, physiological reponses, and active components accumulation in E. pubescensunder phosphorus deficiency treatment, and integrated transcriptome and miRNA analysis, so as to offer comprehensive insights into the adaptive mechanisms employed by E. pubescens in response to phosphorus deficiency across various stages of phosphorus treatment. Remarkably, our findings indicate that phosphorus deficiency induces root growth stimulation in E. pubescens, while concurrently inhibiting the growth of leaves, which are of medicinal value. Surprisingly, this stressful condition results in an augmented accumulation of active components in the leaves. During the early stages (30 days), leaves respond by upregulating genes associated with carbon metabolism, flavonoid biosynthesis, and hormone signaling. This adaptive response facilitates energy production, ROS scavenging, and morphological adjustments to cope with short-term phosphorus deficiency and sustain its growth. As time progresses (90 days), the expression of genes related to phosphorus cycling and recycling in leaves is upregulated, and transcriptional and post-transcriptional regulation (miRNA regulation and protein modification) is enhanced. Simultaneously, plant growth is further suppressed, and it gradually begins to discard and decompose leaves to resist the challenges of long-term phosphorus deficiency stress and sustain survival. In conclusion, our study deeply and comprehensively reveals adaptive strategies utilized by E. pubescens in response to phosphorus deficiency, demonstrating its resilience and thriving potential under stressful conditions. Furthermore, it provides valuable information on potential target genes for the cultivation of E. pubescens genotypes tolerant to low phosphorus. [ABSTRACT FROM AUTHOR]

Background and aims: Plant and soil microbes can reduce their phosphorus (P)-requirements by replacing phospholipids with non-P containing lipids (e.g., galactolipids, sulfolipids, and betaine lipids). There have been few studies of this process in the field (i.e., in natural ecosystems); thus, it is unclear whether a similar replacement of phospholipids with non-P lipids occurs across natural gradients of soil P-availability. Methods: We compared the membrane lipid profiles of plant leaves, roots, and soil microbial communities between two adjacent native Australian sclerophyll forest ecosystems—one situated on a severely P-deficient sandstone-derived soil and the other on a comparatively P-rich shale-derived soil. The herbaceous species, Lomandra longifolia, which occurred across both soils was sampled, along with two Myrtaceae tree species associated with each soil type. Results: The phospholipid content of plant leaves and soil microbes was two- to three-fold greater in the shale site than the sandstone site, but non-P lipid content did not differ between sites. Conclusion: Our results indicate that plants and soil microbes can have a lower investment of P into phospholipids in response to P-deficiency without a concomitant increase in non-P lipid content. Modulations in phospholipid concentration occurred across all plant- and soil microbial-associated phospholipid classes. [ABSTRACT FROM AUTHOR]

Background and aims: The addition of functional soil microbes to the soil can enhance the utilization of soil phosphorus (P) for plants, but the mechanisms underlying this process are not fully understood. The study aimed to investigate the effects of inoculating phosphate-solubilizing microorganisms (PSMs), with or without arbuscular mycorrhizal fungi (AMF), on Phyllostachys edulis seedling growth in soils with varying P levels. Methods: The pot experiment was conducted on P. edulis seedings with inoculation treatments of a mixture of 15 PSMs from the P. edulis rhizosphere alone, or PSMs in cooperation with AMF. Plant mass and nutrient concentrations, soil properties and soil microbial communities were assessed when the seedlings had completed their first-year growth spurt (T1) and second-year growth spurt (T2). Results: The application of PSMs, particularly in combination with AMF, resulted in significant increases in seedling mass and nutrient content under P-deficient conditions, accomplished through modifications in soil nutrient concentrations and enzyme activities related to nitrogen, carbon, and P metabolism. The beneficial outcomes were accompanied by alterations in the composition and interactions within the constituents of the rhizosphere microbial community. Remarkably, the co-inoculation of AMF and PSMs led to a higher abundance of microorganisms that promote plant growth within the rhizosphere. Conclusion: The utilization of PSMs, especially in combination with AMF, proves to be an effective strategy for enhancing P. edulis seedlings growth during their second-year growth, particularly in P-deficient soil. This approach modifies the soil microenvironment, offering a promising avenue for improving soil P utilization by woody plants. [ABSTRACT FROM AUTHOR]

Nitrogen fixation, occurring through the symbiotic relationship between legumes and rhizobia in root nodules, is crucial in sustainable agriculture. Nodulation and soybean production are influenced by low levels of phosphorus stress. In this study, we discovered a MADS transcription factor, GmAGL82, which is preferentially expressed in nodules and displays significantly increased expression under conditions of phosphate (Pi) deficiency. The overexpression of GmAGL82 in composite transgenic plants resulted in an increased number of nodules, higher fresh weight, and enhanced soluble Pi concentration, which subsequently increased the nitrogen content, phosphorus content, and overall growth of soybean plants. Additionally, transcriptome analysis revealed that the overexpression of GmAGL82 significantly upregulated the expression of genes associated with nodule growth, such as GmENOD100, GmHSP17.1, GmHSP17.9, GmSPX5, and GmPIN9d. Based on these findings, we concluded that GmAGL82 likely participates in the phosphorus signaling pathway and positively regulates nodulation in soybeans. The findings of this research may lay the theoretical groundwork for further studies and candidate gene resources for the genetic improvement of nutrient-efficient soybean varieties in acidic soils. [ABSTRACT FROM AUTHOR]

This study assessed the effect of Bacillus megaterium on seedling growth of Glycyrrhiza uralensis Fisch. under control and phosphorus (P) deficiency conditions. The results showed that P deficiency improved 1) G. uralensis root growth, 2) superoxide dismutase, catalase, and peroxidase activities, 3) inorganic P, starch, and soluble sugar contents in roots, 4) dissipated energy flux per reaction center, trapped energy flux per reaction center, and absorption flux per reaction center, and 5) net photosynthetic rate, stomatal conductance, transpiration rate, maximum fluorescence intensity after dark adaptation, and variable fluorescence. However, P deficiency significantly decreased chlorophyll and carotenoid contents in G. uralensis, but enhanced chlorophyll and carotenoid contents in B. megaterium. Our findings on the regulatory mechanisms of B. megaterium in response to P starvation hold promise for improving the success of G. uralensis cultivation. [ABSTRACT FROM AUTHOR]

Summary: The continuous imbalance between nitrogen (N) and phosphorus (P) deposition is expected to shift many ecosystems from N‐ to P limitation. Extraradical hyphae of ectomycorrhizal (ECM) fungi play important roles in plant nutrient acquisition under nutrient deficiency. However, whether and how ECM hyphae enhance soil P availability to alleviate N‐induced P deficiency remains unclear.We investigated the impacts of ECM hyphae on transformations among different soil P fractions and underlying mechanisms under N deposition in two ECM‐dominated forests.Ectomycorrhizal hyphae enhanced soil P availability under N addition by stimulating mineralization of organic P (Po) and desorption and solubilization of secondary mineral P, as indicated by N‐induced increase in positive hyphal effect on plant‐available P pool and negative hyphal effects on Po and secondary mineral P pools. Moreover, ECM hyphae increased soil phosphatase activity and abundance of microbial genes associated with Po mineralization and inorganic P solubilization, while decreasing concentrations of Fe/Al oxides.Our results suggest that ECM hyphae can alleviate N‐induced P deficiency in ECM‐dominated forests by regulating interactions between microbial and abiotic factors involved in soil P transformations. This advances our understanding of plant acclimation strategies via mediating plant–mycorrhiza interactions to sustain forest production and functional stability under changing environments. [ABSTRACT FROM AUTHOR]

Summary: Triphyophyllum peltatum, a rare tropical African liana, is unique in its facultative carnivory. The trigger for carnivory is yet unknown, mainly because the plant is difficult to propagate and cultivate. This study aimed at identifying the conditions that result in the formation of carnivorous leaves.In vitro shoots were subjected to abiotic stressors in general and deficiencies of the major nutrients nitrogen, potassium and phosphorus in particular, to trigger carnivorous leaves' development. Adventitious root formation was improved to allow verification of the trigger in glasshouse‐grown plants.Among all the stressors tested, only under phosphorus deficiency, the formation of carnivorous leaves was observed. These glandular leaves fully resembled those found under natural growing conditions including the secretion of sticky liquid by mature capture organs. To generate plants for glasshouse experiments, a pulse of 55.4 μM α‐naphthaleneacetic acid was essential to achieve 90% in vitro rooting. This plant material facilitated the confirmation of phosphorus starvation to be essential and sufficient for carnivory induction, also under ex vitro conditions.Having established the cultivation of T. peltatum and the induction of carnivory, future gene expression profiles from phosphorus starvation‐induced leaves will provide important insight to the molecular mechanism of carnivory on demand. [ABSTRACT FROM AUTHOR]

Background and Aims: The leaf economic spectrum (LES) is related to dry mass and nutrient investments towards photosynthetic processes and leaf structures, and to the duration of returns on those investments (leaf lifespan, LL). Phosphorus (P) is a key limiting nutrient for plant growth, yet it is unclear how the allocation of leaf P among different functions is coordinated with the LES. We addressed this question among 12 evergreen woody species co-occurring on P-impoverished soils in south-eastern Australia. Methods: Leaf 'economic' traits, including LL, leaf mass per area (LMA), light-saturated net photosynthetic rate per mass (Amass), dark respiration rate, P concentration ([Ptotal]), nitrogen concentration, and P resorption, were measured for three pioneer and nine non-pioneer species. Leaf P was separated into five functional fractions: orthophosphate P (Pi), metabolite P (PM), nucleic acid P (PN), lipid P (PL), and residual P (PR; phosphorylated proteins and unidentified compounds that contain P). Results: LL was negatively correlated with Amass and positively correlated with LMA, representing the LES. Pioneers occurred towards the short-LL end of the spectrum and exhibited higher [Ptotal] than non-pioneer species, primarily associated with higher concentrations of Pi, PN and PL. There were no significant correlations between leaf P fractions and LL or LMA, while Amass was positively correlated with the concentration of PR. Conclusions: Allocation of leaf P to different fractions varied substantially among species. This variation was partially associated with the LES, which may provide a mechanism underlying co-occurrence of species with different ecological strategies under P limitation. [ABSTRACT FROM AUTHOR]

Acid soils occupy approximately 50% of potentially arable lands. Improving crop productivity in acid soils, therefore, will be crucial for ensuring food security and agricultural sustainability. High soil acidity often coexists with phosphorus (P) deficiency and aluminum (Al) toxicity, a combination that severely impedes crop growth and yield across wide areas. As roots explore soil for the nutrients and water required for plant growth and development, they also sense and respond to below-ground stresses. Within the terrestrial context of widespread P deficiency and Al toxicity pressures, plants, particularly roots, have evolved a variety of mechanisms for adapting to these stresses. As legumes, soybean (Glycine max) plants may acquire nitrogen (N) through symbiotic nitrogen fixation (SNF), an adaptation that can be useful for mitigating excessive N fertilizer use, either directly as leguminous crop participants in rotation and intercropping systems, or secondarily as green manure cover crops. In this review, we investigate legumes, especially soybean, for recent advances in our understanding of root-based mechanisms linked with root architecture modification, exudation and symbiosis, together with associated genetic and molecular strategies in adaptation to individual and/or interacting P and Al conditions in acid soils. We propose that breeding legume cultivars with superior nutrient efficiency and/or Al tolerance traits through genetic selection might become a potentially powerful strategy for producing crop varieties capable of maintaining or improving yields in more stressful soil conditions subjected to increasingly challenging environmental conditions. [ABSTRACT FROM AUTHOR]

Aims: Rainfed rice in subSaharan Africa suffers from combined drought and phosphorus (P) deficiency stresses. Enhanced root development under water stress may counteract the physical effects of drought lowering soil P bioavailability. This study was set up to evaluate how rice genotypes respond differently to variable water stress in P deficient conditions. Methods: A greenhouse study was conducted with a full factorial combination of six genotypes, two soil P treatments (strong to moderate P deficiency) and two irrigation (W) regimes (rainfed limited and adequate). Plants were grown for 49 days and root traits were measured. Results: The overall effects of P supply on shoot weight were larger than overall effects of water supply, water stress effects were most pronounced at highest P supply because of the higher transpiration in larger plants. Reduced water supply did not enhance P stress, and the stress antagonisms were genotype dependent. There was no genotypic variation in the increased root development in response to drought that would lead to increased P uptake. Root weight and root efficiency mainly explained shoot P content across all water treatments and genotypes with marginal effects of root architectural traits. Conclusion: This study illustrates the importance of root biomass production and root efficiency under the combined stresses of water and P and corroborated the superior performance of genotypes Chhomrong Dhan and FOFIFA 172 that was found in the field. [ABSTRACT FROM AUTHOR]

The 3HV content of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)), a biobased and biodegradable polyester, must be controlled for improved thermomechanical properties. Propionic acid (PA) is the main acid allowing 3HV monomer biosynthesis which is present in volatile fatty acid mixes produced from agro-industrial coproducts acidogenesis. With the strain Cupriavidus necator, we investigated the impact of carbon-limiting vs. carbon-overflow conditions thanks to fed-batch cultures, with sequential or continuous feeding of propionic acid as the sole carbon source, and phosphorus deficiency conditions. Regardless of the C-limiting continuous specific feeding rate imposed (i.e., below the determined critical specific feeding rate (q PAcrit) of 0.24 Cmol.Cmol−1.h−1), a regular incorporation of the 3HV in the copolymer at a content of 23 ± 4 mol% was observed with a high molecular weight (≈ 1000 kDa) and a remarkably low polydispersity index (≈ 1.5). This feeding strategy maximized both the productivity (up to 0.78 g.L−1.h−1) and conversion yield of propionic acid into P(3HB-co-3HV) (up to 0.59 Cmol.Cmol−1) if operated close to q PAcrit. With C-overflow sequential feeding (i.e., above q PAcrit), the residual propionic acid concentration has been highlighted as a key parameter in 3HV content improvement (≥ 44 mol%) even though it occurred at the expense of the copolymer yield and productivity. [Display omitted] • C-overflow conditions vs C-limiting conditions were studied. • Propionic acid (PA) feeding rate investigated to tailor P(3HB-co-3HV) synthesis. • Critical PA specific uptake rate (q PAcrit) determined at 0.24 Cmole.Cmole−1.h−1. • Below q PAcrit , a regular random copolymer produced with 23 ± 4 mol% 3HV. • Above q PAcrit , PA accumulation in the medium lead to increased 3HV content. [ABSTRACT FROM AUTHOR]

Allelopathy is a phenomenon in which plants exude biochemicals that inhibit the growth of nearby plants. Allelopathic activity and biochemical production are induced by environmental stresses. This study investigated the effect of phosphorus (P) deficiency on growth and allelopathic activities in two landrace rice cultivars of southern Thailand, Nang loy and Niaw look pueng. Rice seedlings were hydroponically grown for 14 days in Yoshida Solution with normal (HP) and low (LP) P concentrations. Growth and phosphate (Pi) contents in rice seedlings were determined to evaluate the difference in internal P status between plants grown under the HP and LP conditions. Water extracts were prepared from shoots and roots of rice seedlings to test allelopathic activity against lettuce seedlings. The results showed that rice seedlings responded to P deficiency by reducing shoot and root Pi content and increasing leaf greenness. Changes in seedling growth were scarcely detected in the young rice seedlings. In a germination assay, water extracts of P-deficient seedlings from both rice cultivars lowered germination indices and inhibited lettuce seedling growth. Furthermore, shoot extracts of the same rice cultivar more strongly inhibited the development of lettuce seedlings than root extracts. The greater allelopathic activity of the shoot extracts might be a result of their higher phenolic contents, which could be induced by P deficiency. Therefore, an allelopathic trait of rice seedlings is an early response to P deficiency prior to growth inhibition under the low P condition. [ABSTRACT FROM AUTHOR]

can provide useful information about P adsorption and the factors affecting it. A batch experiment was performed with phosphorus concentrations (0 to 35 mg/L) in two soils with different electrical conductivity (EC) (2 and 15 dSm-1 ) by a variety of biochar treatments including simple apple-grape biochar (BC), rock phosphate- biochar (BC-RP), enrichedbiochar (BC-H3PO4-RP), enriched-biochar (BC-HCl-RP), triple superphosphate (TSP), and control (Cont). The results indicated that phosphorus sorption capacity varied between the soils. Biochar treatments were effective in reducing the phosphorus adsorption of both soils. Due to BC-H3PO4-RP and BC-HCl-RP treatments, the maximum phosphorus adsorption of soils decreased in S1 soil by 14 and 23 % and in S2 soil by 26 and 19%, respectively. Also, the use of these treatments decreased the parameters of Langmuir absorption intensity (KL) of S1 soil to 0.085 and 0.066, respectively and S2 soil to 0.11 and 0.15, L/mg respectively, and Freundlich absorption capacity (KF) of S1 soil decreased to 19.2 and 22.5 and S2 soil to 28.2 and 28.1 L/kg, respectively. Enriched biochars significantly reduced the buffering indices of both soils indicating phosphorus adsorption decreased and increased the availability of phosphorus for the plant. The standard phosphorus requirement of S2 soil was lower than S1 soil by both equations. Therefore, enriched biochar can be an effective strategy to increase phosphorus availability and reduce the use of chemical fertilizers in saline and non-saline conditions; however, more field studies are needed for a clear understanding of the potential of P-enriched biochar as a fertilizer alternative. [ABSTRACT FROM AUTHOR]

Emerging evidence reveals that the three-dimensional (3D) chromatin architecture plays a key regulatory role in various biological processes of plants. However, information on the 3D chromatin architecture of the legume model plant Medicago truncatula and its potential roles in the regulation of response to mineral nutrient deficiency are very limited. Using high-resolution chromosome conformation capture sequencing, we identified the 3D genome structure of M. truncatula in terms of A/B compartments, topologically associated domains (TADs) and chromatin loops. The gene density, expressional level, and active histone modification were higher in A compartments than in B compartments. Moreover, we analysed the 3D chromatin architecture reorganization in response to phosphorus (P) deficiency. The intra-chromosomal cis -interaction proportion was increased by P deficiency, and a total of 748 A/B compartment switch regions were detected. In these regions, density changes in H3K4me3 and H3K27ac modifications were associated with expression of P deficiency-responsive genes involved in root system architecture and hormonal responses. Furthermore, these genes enhanced P uptake and mobilization by increasing root surface area and strengthening signal transduction under P deficiency. These findings advance our understanding of the potential roles of 3D chromatin architecture in responses of plants in general, and in particular in M. truncatula , to P deficiency. [ABSTRACT FROM AUTHOR]

Background: In recent years, the response of cotton (Gossypium hirsutum L.) root morphology and rhizosphere processes to phosphorus (P) deficiency have attracted extensive attention. However, the dynamics of root morphology and physiology to shoot P concentration (SPC) under various P conditions remain unclear. Aim: We aimed to determine the changes in root morphology and physiology and their relationships with SPC under different levels of P supply. Method: The cotton cultivars XLZ13 and XLZ19 were grown in a hydroponic experiment with seven rates of P supply (0–2.0 mM P L−1) and in a root box experiment with seven P levels (0–400 mg P kg−1). Root morphological and physiological parameters were determined 60 days after planting (hydroponic experiment) and 75 days after transplanting (root box experiment). Results: Cotton plant growth, P uptake, and root morphology differed significantly between the two genotypes and among the P levels. Cotton plants had the maximum shoot biomass when the SPC of XLZ13 and XLZ19 were 4.6–5.9 mg g−1 and 3.9‐5.0 mg g−1, respectively. Total and specific root lengths initially increased with increasing SPC and peaked at an SPC of XLZ13 and XLZ19 about 6.0–7.0 mg g−1 and 4.0‐5.0 mg g−1, respectively. Root physiological responses (rhizosphere acidification, acid phosphatase [Apase] activity) decreased as the SPC increased. Conclusions: The critical SPC for optimal root morphology were 5–6 mg g−1. P deficiency did not induce rhizosphere acidification but promoted root and rhizosphere APase activity. [ABSTRACT FROM AUTHOR]

Soybean growth is frequently hampered by a lack of phosphorus (P). This study aimed to screen soybean cultivars for low P tolerance using cultivars from the Japanese core collection. Eighty-one soybean cultivars were grown in soil cultures for 25 days after transplanting. The plants were subjected to P treatment (− P treatment: 0 g P2O5 kg−1 soil; and + P treatment: 1 g P2O5 kg−1 soil). Shoot dry weight, root length, P concentration, and P uptake were measured at 25 days after transplanting. Low P-tolerant and low P-sensitive cultivars were selected based on multiple criteria, including shoot dry weight, P utilization efficiency, and low P tolerance (LPT) value. The shoot dry weight of 30 soybean cultivars was lower in − P than in + P. The root length showed a significant and positive correlation with P uptake, P utilization efficiency, and dry weight in the − P and + P treatments. The LPT values of soybean cultivars ranged from 8 to 160%. The low P-tolerant and -sensitive soybean cultivars can be used as study materials in future studies to elucidate the mechanism of low P tolerance in soybeans. [ABSTRACT FROM AUTHOR]

Background: Phosphorus (P) is one of the most essential macronutrients for crops. The growth and yield of peanut (Arachis hypogaea L.) are always limited by P deficiency. However, the transcriptional and metabolic regulatory mechanisms were less studied. In this study, valuable phenotype, transcriptome and metabolome data were analyzed to illustrate the regulatory mechanisms of peanut under P deficiency stress. Result: In present study, two treatments of P level in deficiency with no P application (–P) and in sufficiency with 0.6 mM P application (+ P) were used to investigate the response of peanut on morphology, physiology, transcriptome, microRNAs (miRNAs), and metabolome characterizations. The growth and development of plants were significantly inhibited under –P treatment. A total of 6088 differentially expressed genes (DEGs) were identified including several transcription factor family genes, phosphate transporter genes, hormone metabolism related genes and antioxidant enzyme related genes that highly related to P deficiency stress. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that 117 genes were annotated in the phenylpropanoid biosynthesis pathway under P deficiency stress. A total of 6 miRNAs have been identified significantly differential expression between + P and –P group by high-throughput sequencing of miRNAs, including two up-regulated miRNAs (ahy-miR160-5p and ahy-miR3518) and four down-regulated miRNAs (ahy-miR408-5p, ahy-miR408-3p, ahy-miR398, and ahy-miR3515). Further, the predicted 22 target genes for 6 miRNAs and cis-elements in 2000 bp promoter region of miRNA genes were analyzed. A total of 439 differentially accumulated metabolites (DAMs) showed obviously differences in two experimental conditions. Conclusions: According to the result of transcripome and metabolome analyses, we can draw a conclusion that by increasing the content of lignin, amino acids, and levan combining with decreasing the content of LPC, cell reduced permeability, maintained stability, raised the antioxidant capacity, and increased the P uptake in struggling for survival under P deficiency stress. [ABSTRACT FROM AUTHOR]

A study was conducted at Bangladesh Agricultural Research Institute's greenhouse with 48 maize genotypes through hydroponic culture. Two levels of treatment, namely, low phosphorus (LP) (2.5 × 10-6 mol L-1 of KH2PO4) and normal phosphorus (NP) (2.5 × 10-4 mol L-1 of KH2PO4), were used for this study. Morphologically, plants behave differently in low phosphorus conditions than in normal phosphorus environments. Large augmented roots were found in the plant in low phosphorus conditions. The results revealed that chlorophyll contents, shoot length, root length shoot dry weight, root dry weight, leaf area, and root/shoot ratio might be considered critical traits for screening low phosphorus tolerant maize at the seedling stage. The first four principal components (PCs) described 89% of the total variation. Forty-eight maize genotypes formed four main groups or clusters. Among these four cluster groups, except for the SPAD value, the highest number of the mean values for root length, shoot length, root/shoot ratio, root volume, leaf area, root dry weight, shoot dry weight, and total dry weight were obtained from cluster group three. By constructing a genotype × trait biplot with nine traits recorded in 48 genotypes, the highest positive relationship was recorded in total dry weight (TDW) with root dry weight (RDW), shoot dry weight (SDW), and root volume (RV). The results revealed that the SPAD value was weakly correlated with other traits. In the current study, the studied characters were highly heritable. Based on the performance, G10, G18, G23, G27, G29, G33, and G34 could be considered low phosphorus tolerant genotypes. The results of combining abilities revealed that the genotypes G9, G13, G29, G31, and G39 could be used as parents in breeding activities. The present study offers guidelines for plant breeders to develop low phosphorus tolerant maize cultivars for the sustainability of maize production in the modern era of the changing climate. [ABSTRACT FROM AUTHOR]

Selenium (Se) is a beneficial element for higher plants; however, its involvement in improving the plants availability to soil nutrients has not been adequately addressed. Onion (Allium cepa L.) plants were grown under the sufficient (2 mM) and deficient (0.05 mM) phosphorus (P) supply and inoculated with an arbuscular mycorrhizal fungus (AMF, Diversispora versiformis) in the absence or presence of 20 or 80 µg Se L–1 applied as Na2SeO4 under greenhouse conditions. Phosphorus deficiency impaired both shoot and root growth, while mycorrhisation increased plants biomass and root length by up to two times, accompanied by increased potassium uptake, levels of non-structural carbohydrates, protein and amino acids in the leaves and roots. AMF’s impact on biomass production was enhanced by Se supplementation, and the rates of photosynthesis and nitrogen assimilation were also boosted. Besides, AMF effects on the root activity of phosphatase, the acidification of rhizosphere and the mobilisation of insoluble P in the substrate were significantly exacerbated by Se. Our results showed a strong synergistic effect between Se and AMF in improving the plants performance on P-impoverished soils via enhanced ability to solubilise non-labile P fractions in the substrate and stimulation of carbon and nitrogen metabolism. [ABSTRACT FROM AUTHOR]

Grain legumes / cereals intercropping systems with microbial inoculants, hold promise for improving crop productivity under stressful conditions. However, the tripartite interaction involving intercropping system, associated microbiota and stress combining water deficit and low phosphorus (P) availability remains understudied. This study evaluated the impact of three bacterial consortia (C 4 , C 6 , and C ref containing Rhizobium and PSB strains) including single Rhizobium (Rhizobium laguerreae) on the agro-physiological performance of wheat (Triticum durum) and faba bean (Vicia faba) grown as intercrops or sole-crops under P and water deficient conditions. Inoculation, especially with C 6 , significantly improved shoot and root biomasses of both wheat (up to 66 and 81 %) and faba bean (up to 54 and 266 %) intercrops compared to single Rhizobium inoculation and control treatments. Intercropping generally outperformed sole-cropping in above-ground physiology, root morphological traits, shoot and root P content, with a notable effect in response to C 6 exhibiting low microbial biomass P. Changes in bacterial community structure were primarily driven by cropping pattern and water regime rather than bacterial inoculation. Intercropping maintained bacterial diversity but shifted community structure, favoring Proteobacteria. Overall, inoculating intercropped wheat and faba bean with Rhizobium -containing consortia induced beneficial below-ground interspecies interactions under water and P-limiting conditions. • Rhizobium-containing bacterial consortia enhanced belowground interactions in wheat/faba bean intercrops. • Inoculation enhanced root traits and phosphorus dynamics in rhizosphere soil of both intercropped wheat and faba bean plants. • Water regime and cropping pattern rather than inoculation drove shifts in bacterial community structure. • Bacterial consortia enhanced growth performance of intercropping over sole cropping under low P-availability. [ABSTRACT FROM AUTHOR]

Raphidiopsis raciborskii can cause harmful cyanobacterial blooms when concentrations of environmental phosphorus (P) are very low, thus the physiological and molecular mechanisms involved in the acclimation to P need to be characterized better. The growth, chlorophyll fluorescence, alkaline phosphatase, and expression of genes directly involved in P assimilation were compared in the R. raciborskii FACHB 1496 strain grown with and without inorganic P. The specific growth rate (μ), Chl a, and six fluorescence parameters (minimal fluorescence (F0), maximal fluorescence (Fm), maximal variable fluorescence (Fv), electron transport flux (further than QA) per RC (ET0/RC), quantum yield of the electron transport in PSII (ØE0), and the probability that an electron from a trapped exciton is moved into the electron transport chain beyond QA− (ψ0)) markedly decreased in R. raciborskii in response to experimental P-deficiency. In contrast, the relative variable fluorescence at the J-step (VJ), trapped energy flux (leading to QA reduction) per RC (TR0/RC), and alkaline phosphatase activity significantly increased. In addition, gene expressions involved in the alkaline phosphatase (phoA1 and phoA2), high-affinity inorganic P transporter (pstS1), phosphonate transporter and metabolism (phnD and phnM), and nucleotidase (nucH) were significantly upregulated under P deficiency. However, physiological and molecular responses were resumed rapidly after P re-supplementation following P-deficient conditions. Our results highlight that R. raciborskii can perform coordinated and complex cellular and physiological responses to cope with P deficiency, reflecting R. raciborskii's multi-faceted machinery to respond to environmental P fluctuations. [ABSTRACT FROM AUTHOR]

Phosphorus (P) deficiency heterogeneously affected plant nutritional status and physiological performance, ultimately leading to a severe yield reduction. A few putative long non-coding RNAs (lncRNAs) responding to P-starvation in the model crops Arabidopsis thaliana and Oryza sativa have been characterized. White lupin (Lupinus albus) is of prime importance, and is a legume with increasing agronomic value as a protein crop as it exhibits extreme tolerance to nutrient deficiency, particularly P deficiency. Despite its adapted nature to P deficiency, nothing is known about low P-induced lncRNAs in white lupin roots. To address this issue, we identified 39,840 mRNA and 2028 lncRNAs in the eight developmental stages of white lupin root (S0–S7 and lateral root, LR) grown under P deficiency. From these 2028 lncRNAs, 1564 were intergenic and 464 natural antisense intergenic transcript (NAT) lncRNAs. We further predicted six potential targets of miRNAs with twelve lncRNAs, which may regulate P-deficiency-related processes. Moreover, the weighted gene co-expression network analysis (WGCNA) revealed seven modules that were correlated with the expression pattern of lncRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed 606 GO terms and 27 different pathways including signal transduction, energy synthesis, detoxification, and Pi transport. In addition, we screened 13 putative lncRNAs that showed a distinct expression pattern in each root, indicating their role in the P deficiency regulatory network. Therefore, white lupin may be a reference legume to characterize P-deficiency-responsive novel lncRNAs, which would highlight the role of lncRNAs in the regulation of plant responses to P deficiency. [ABSTRACT FROM AUTHOR]

Galactolipids are essential to compensate for the loss of phospholipids by 'membrane lipid remodelling' in plants under phosphorus (P) deficiency conditions. Monogalactosyl diacylglycerol (MGDG) synthases catalyse the synthesis of MGDG which is further converted into digalactosyl diacylglycerol (DGDG), later replacing phospholipids in the extraplastidial membranes. However, the roles of these enzymes are not well explored in rice. In this study, the rice MGDG synthase 3 gene (OsMGD3) was identified and functionally characterized. We showed that the plant phosphate (Pi) status and the transcription factor PHOSPHATE STARVATION RESPONSE 2 (OsPHR2) are involved in the transcriptional regulation of OsMGD3. CRISPR/Cas9 knockout and overexpression lines of OsMGD3 were generated to explore its potential role in rice adaptation to Pi deficiency. Compared with the wild type, OsMGD3 knockout lines displayed a reduced Pi acquisition and utilization while overexpression lines showed an enhancement of the same. Further, OsMGD3 showed a predominant role in roots, altering lateral root growth. Our comprehensive lipidomic analysis revealed a role of OsMGD3 in membrane lipid remodelling, in addition to a role in regulating diacylglycerol and phosphatidic acid contents that affected the expression of Pi transporters. Our study highlights the role of OsMGD3 in affecting both internal P utilization and P acquisition in rice. [ABSTRACT FROM AUTHOR]

A serious acidification trend currently affects paddy soil and soil phosphorus (P) availability has declined in rice production. This study investigated the effect of rice-straw biochar on P availability and the adaptability of rice roots in acidified soil. Rice was grown in rhizoboxes, allowing for the precise sampling of rhizosphere and bulk soil for the sequential extraction of P fractions. Biochar may provide a liming effect and strong nutrient adsorption, leading to soil improvement. The results confirmed that biochar application significantly improved plant growth and P accumulation in shoots by 29% and 75%, respectively. However, the application of washed biochar and equivalent lime only increased shoot biomass and P accumulation by 13.4% and 11.2%, and by 42% and 38%, respectively. Compared with the control, applying biochar increased the plant-available P component contents in rhizosphere and bulk soil. Biochar affected the chemical balance among the different P fractions, increased aluminum-bound phosphate (Al-P) pool, calcium-bound phosphate (Ca-P) pool and decreased the occluded phosphate pool in acidic paddy soil. Biochar amendment significantly improved root growth of and increased the citrate exudation from roots under low P supply, accompanied by the enhanced expression of the anion-transporter-related OsFRDL4 gene and the OsPT1 phosphate transporter. The results showed that biochar application in degraded acidic soils could improve rice potential for P acquisition to increase available P component and maintain high citrate exudation. [ABSTRACT FROM AUTHOR]

Background: Modification of histone acetylation is a ubiquitous and reversible process in eukaryotes and prokaryotes and plays crucial roles in the regulation of gene expression during plant development and stress responses. Histone acetylation is co-regulated by histone acetyltransferase (HAT) and histone deacetylase (HDAC). HAT plays an essential regulatory role in various growth and development processes by modifying the chromatin structure through interactions with other histone modifications and transcription factors in eukaryotic cells, affecting the transcription of genes. Comprehensive analyses of HAT genes have been performed in Arabidopsis thaliana and Oryza sativa. However, little information is available on the HAT genes in foxtail millet (Setaria italica [L.] P. Beauv). Results: In this study, 24 HAT genes (SiHATs) were identified and divided into four groups with conserved gene structures via motif composition analysis. Phylogenetic analysis of the genes was performed to predict functional similarities between Arabidopsis thaliana, Oryza sativa, and foxtail millet; 19 and 2 orthologous gene pairs were individually identified. Moreover, all identified HAT gene pairs likely underwent purified selection based on their non-synonymous/synonymous nucleotide substitutions. Using published transcriptome data, we found that SiHAT genes were preferentially expressed in some tissues and organs. Stress responses were also examined, and data showed that SiHAT gene transcription was influenced by drought, salt, low nitrogen, and low phosphorus stress, and that the expression of four SiHATs was altered as a result of infection by Sclerospora graminicola. Conclusions: Results indicated that histone acetylation may play an important role in plant growth and development and stress adaptations. These findings suggest that SiHATs play specific roles in the response to abiotic stress and viral infection. This study lays a foundation for further analysis of the biological functions of SiHATs in foxtail millet. [ABSTRACT FROM AUTHOR]

Phosphate deficiency and drought are significant environmental constraints that impact both the productivity and quality of wheat. The interaction between phosphorus and water facilitates their mutual absorption processes in plants. Under conditions of both phosphorus deficiency and drought stress, we observed a significant upregulation in the expression of wheat MYB-CC transcription factors through the transcriptome analysis. 52 TaMYB-CC genes in wheat were identified and analyzed their evolutionary relationships, structures, and expression patterns. The TaMYB-CC5 gene exhibited specific expression in roots and demonstrated significant upregulation under phosphorus deficiency and drought stress compared to other TaMYB-CC genes. The overexpression of TaMYB-CC5A in Arabidopsis resulted in a significant increase of root length under stress conditions, thereby enhancing tolerance to phosphate starvation and drought stress. The wheat lines with silenced TaMYB-CC5 genes exhibited reduced root length under stress conditions and increased sensitivity to phosphate deficiency and drought stress. In addition, silencing the TaMYB-CC5 genes resulted in altered phosphorus content in leaves but did not lead to a reduction in phosphorus content in roots. Enrichment analysis the co-expression genes of TaMYB-CC5 transcription factors, we found the zinc-induced facilitator-like (ZIFL) genes were prominent associated with TaMYB-CC5 gene. The TaZIFL1 , TaZIFL2 , and TaZIFL5 genes were verified specifically expressed in roots and regulated by TaMYB-CC5 transcript factor. Our study reveals the pivotal role of the TaMYB-CC5 gene in regulating TaZIFL genes, which is crucial for maintaining normal root growth under phosphorus deficiency and drought stress, thereby enhanced resistance to these abiotic stresses in wheat. • The TaMYB-CC5 exhibited specific expression in roots, and was induced by both phosphorus deficiency and drought stress. • The TaMYB-CC5 exhibited binding to the promoter of TaZIFLs genes, and influenced the expression of TaZIFLs genes in wheat roots. • TaMYB-CC5 gene enhances tolerance of drought and phosphorus deficiency by maintaining root growth under stress condition. [ABSTRACT FROM AUTHOR]

Background and Aims Initiation of cluster roots in white lupin (Lupinus albus) under phosphorus (P) deficiency requires auxin signalling, whereas flavonoids inhibit auxin transport. However, little information is available about the interactions between P deficiency and flavonoids in terms of cluster-root formation in white lupin. Methods Hydroponic and aeroponic systems were used to investigate the role of flavonoids in cluster-root formation, with or without 75 μ m P supply. Key Results Phosphorus-deficiency-induced flavonoid accumulation in cluster roots depended on developmental stage, based on in situ determination of fluorescence of flavonoids and flavonoid concentration. LaCHS8 , which codes for a chalcone synthase isoform, was highly expressed in cluster roots, and silencing LaCHS8 reduced flavonoid production and rootlet density. Exogenous flavonoids suppressed cluster-root formation. Tissue-specific distribution of flavonoids in roots was altered by P deficiency, suggesting that P deficiency induced flavonoid accumulation, thus fine-tuning the effect of flavonoids on cluster-root formation. Furthermore, naringenin inhibited expression of an auxin-responsive DR5:GUS marker, suggesting an interaction of flavonoids and auxin in regulating cluster-root formation. Conclusions Phosphorus deficiency triggered cluster-root formation through the regulation of flavonoid distribution, which fine-tuned an auxin response in the early stages of cluster-root development. These findings provide valuable insights into the mechanisms of cluster-root formation under P deficiency. [ABSTRACT FROM AUTHOR]

Aims: Root exudation of organic acids is one of strategies for tropical trees to facilitate nutrient uptake from the highly weathered soils. However, paradoxical relationship remains that root exudation also stimulates microbial activities to consume organic acids in the rhizosphere (root-soil interface). Plant-specific root exudation might shape different rhizosphere carbon (C) cycles in soils under different tree species. We test whether root exudation and rhizosphere C fluxes of organic acids and sugars differ between soils under dominant dipterocarp trees (Dipterocapus cornutus and Shorea laevis) and pioneer trees (Macaranga spp.). Methods: We measured (1) root exudation from mature trees, (2) soil solution concentrations of organic acids and monosaccharides, and (3) mineralization kinetics of 14C-radiolabelled substrates in the rhizosphere and bulk soils of the Dipterocarp and Macaranga trees. Results: Malate was a dominant organic acid exuded from Dipterocarp roots, while monosaccharides were dominant exudates of pioneer Macaranga trees. Malate exudation rates by Dipterocarp roots were greater compared to Macaranga roots. Organic acid exudation increased with increasing root surface area and with decreasing soil pH. Microbial activities of malate mineralization were enhanced in the rhizosphere both under Dipterocarp and Macaranga trees, but the C fluxes of malate mineralization far exceeded root exudation of malate in the rhizosphere of Dipterocarp trees. Conclusion: Tree species develop different strategies to increase malate concentration in rhizosphere soil directly through root exudation or indirectly through rhizosphere microbial activities to increase malate production, which might be favorable for phosphorus solubilization, aluminum detoxification, and lignin degradation in acidic soils. [ABSTRACT FROM AUTHOR]

Background: Phosphorus is one of the essential elements for plant growth and development, but available phosphorus (Pi) content in many soil types is low. As a fast-growing tree species for timber production, Chinese fir is in great demand of Pi, and the lack of Pi in soil restricts the increase of productivity of Chinese fir plantation. Root morphology and the synthesis and secretion of organic acids play an important role in the uptake of phosphorus, but the molecular mechanisms of Chinese fir root responses to Pi deficiency are largely unexplored. In this study, seedlings of Yang 061 clone were grown under three Pi supply levels (0, 5 and 10 mg·L-1 P) and morphological attributes, organic acid content and enzyme activity were measured. The transcriptome data of Chinese fir root system were obtained and the expression levels of phosphorus responsive genes and organic acid synthesis related genes on citric acid and glyoxylate cycle pathway were determined. Results: We annotated 50,808 Unigenes from the transcriptome of Chinese fir roots. Among differentially expressed genes, seven genes of phosphate transporter family and 17 genes of purple acid phosphatase family were up-regulated by Pi deficiency, two proteins of SPX domain were up-regulated and one was down-regulated. The metabolic pathways of the citric acid and glyoxylate cycle pathway were mapped, and the expression characteristics of the related Unigenes under different phosphorus treatments were analyzed. The genes involved in malic acid and citric acid synthesis were up-regulated, and the activities of the related enzymes were significantly enhanced under long-term Pi stress. The contents of citric acid and malic acid in the roots of Chinese fir increased after 30 days of Pi deficiency. Conclusion: Chinese fir roots showed increased expression of genes related with phosphorus starvation, citrate and malate synthesis genes, increased content of organic acids, and enhanced activities of related enzymes under Pi deficiency. The results provide a new insight for revealing the molecular mechanism of adaption to Pi deficiency and the pathway of organic acid synthesis in Chinese fir roots. [ABSTRACT FROM AUTHOR]

From the veterinarian point of view, the precise assessment of the phosphorus (P) supply of pigs is of great interest, especially in cases of clinical disorders like 'leg weakness' or lameness when bone mineralisation may be disturbed. Thus, the question arises which bone is most suitable for diagnostic purposes and is reflecting changes in dietary P supply most clearly. Thirty- six growing pigs (BHZP db.Viktoria x Piétrain, about eleven weeks old, mean bw: 28.3 ± 3.44 kg) were allotted to three groups differently supplied with P by receiving a diet either supplemented with inorganic P (iP) and phytase (500 FTU/kg; controls/group C), without iP but phytase added (500 FTU/ kg; group 1) or containing only endogenous phytase (group 2). The inclusion of iP resulted in total P contents in diets for group C of 4.76 and 4.23 g/kg as fed from 28 to 57 and >57 kg body weight (bw), respectively. In diets for group 1 and 2, the corresponding P contents were 3.08/2.72 g/kg as fed (group 1) and 3.08/2.88 g/kg as fed (group 2). On days 26, 47 and 82 of the dietary treatment, four pigs of each group were euthanised. Furthermore, four additional pigs were euthanised one day before starting the experiment. Standardised samples of the femur (distal part), tibia/fibula (proximal part) and os metatarsale III (MT III, in toto) were taken during dissection and submitted to chemical analysis. At all time points, pigs of group C had significantly higher ash contents in all types of bone samples compared to pigs from group 1 and 2. Relative differences between means of groups (C = 100%) were less for the ash content in MT III (reduction by up to -9.1%) compared to the distal femur and the proximal tibia/fibula (reduction by up to -23.2 resp. -22.7%). Variation coefficient (irrespective of group and time point) was lower for ash content in MT III (4.29%) compared to the distal femur and the proximal tibia/fibula (both: 11.8%). Under the conditions of this study, ash contents of the distal femur and the proximal tibia/fibula reflected the different P supply more pronounced indicating higher sensitivity compared to MT III. [ABSTRACT FROM AUTHOR]

From the veterinarian point of view, the precise assessment of the phosphorus (P) supply of pigs is of great interest, especially in cases of clinical disorders like 'leg weakness' or lameness when bone mineralisation may be disturbed. Thus, the question arises which bone is most suitable for diagnostic purposes and is reflecting changes in dietary P supply most clearly. Thirty‐six growing pigs (BHZP db.Viktoria x Piétrain, about eleven weeks old, mean bw: 28.3 ± 3.44 kg) were allotted to three groups differently supplied with P by receiving a diet either supplemented with inorganic P (iP) and phytase (500 FTU/kg; controls/group C), without iP but phytase added (500 FTU/kg; group 1) or containing only endogenous phytase (group 2). The inclusion of iP resulted in total P contents in diets for group C of 4.76 and 4.23 g/kg as fed from 28 to 57 and >57 kg body weight (bw), respectively. In diets for group 1 and 2, the corresponding P contents were 3.08/2.72 g/kg as fed (group 1) and 3.08/2.88 g/kg as fed (group 2). On days 26, 47 and 82 of the dietary treatment, four pigs of each group were euthanised. Furthermore, four additional pigs were euthanised one day before starting the experiment. Standardised samples of the femur (distal part), tibia/fibula (proximal part) and os metatarsale III (MT III, in toto) were taken during dissection and submitted to chemical analysis. At all time points, pigs of group C had significantly higher ash contents in all types of bone samples compared to pigs from group 1 and 2. Relative differences between means of groups (C = 100%) were less for the ash content in MT III (reduction by up to −9.1%) compared to the distal femur and the proximal tibia/fibula (reduction by up to −23.2 resp. −22.7%). Variation coefficient (irrespective of group and time point) was lower for ash content in MT III (4.29%) compared to the distal femur and the proximal tibia/fibula (both: 11.8%). Under the conditions of this study, ash contents of the distal femur and the proximal tibia/fibula reflected the different P supply more pronounced indicating higher sensitivity compared to MT III. [ABSTRACT FROM AUTHOR]

Summary: Heterotrimeric G protein is involved in plant growth and development, while the role of rice (Oryza sativa) G protein γ subunit qPE9‐1 in response to low‐phosphorus (LP) conditions remains unclear. The gene expression of qPE9‐1 was significantly induced in rice roots under LP conditions. Rice varieties carrying the qPE9‐1 allele showed a stronger primary root response to LP than the varieties carrying the qpe9‐1 allele (mutant of the qPE9‐1 allele). Transgenic rice plants with the qPE9‐1 allele had longer primary roots and higher P concentrations than those with the qpe9‐1 allele under LP conditions. The plasma membrane (PM) H+‐ATPase was important for the qPE9‐1‐mediated response to LP. Furthermore, OsGF14b, a 14‐3‐3 protein that acts as a key component in activating PM H+‐ATPase for root elongation, is also involved in the qPE9‐1 mediation. Moreover, the overexpression of OsGF14b in WYJ8 (carrying the qpe9‐1 allele) partially increased primary root length under LP conditions. Experiments using R18 peptide (a 14‐3‐3 protein inhibitor) showed that qPE9‐1 is important for primary root elongation and H+ efflux under LP conditions by involving the 14‐3‐3 protein. In addition, rhizosheath weight, total P content, and the rhizosheath soil Olsen‐P concentration of qPE9‐1 lines were higher than those of qpe9‐1 lines under soil drying and LP conditions. These results suggest that the G protein γ subunit qPE9‐1 in rice plants modulates root elongation for phosphorus uptake by involving the 14‐3‐3 protein OsGF14b and PM H+‐ATPase, which is required for rice P use. Significance Statement: The present study suggests that the G protein γ subunit qPE9‐1 in rice (Oryza sativa) plants modulates root elongation for phosphorus uptake by involving the 14‐3‐3 protein OsGF14b and plasma membrane H+‐ATPase, which is required for rice phosphorus use. [ABSTRACT FROM AUTHOR]

In order to further understand the potential mechanisms of grassland structure and function in response to soil phosphorus deficiency under future elevated CO2 concentration, we examined the effects of elevated CO2 concentration and phosphorus deficiency on the stomatal traits and leaf gas exchange parameters of annual ryegrass with environmental growth chambers, where the CO2 concentration was accurately controlled at 400 µmol/mol or 800 µmol/mol and meanwhile these grasses were fertilized with six phosphorus levels including 0.004 mmol/L (P0.004), 0.012 mmol/L (P0.012), 0.02 mmol/L (P0.02), 0.06 mmol/L (P0.06), 0.1 mmol/L (P0.1) and 0.5 mmol/L (P0.5). Our results showed that: (1) The elevated CO2 concentration significantly decreased the stomatal density of plants under lower phosphorus levels, but increased the stomatal density of annual ryegrass grown at higher phosphorus levels (0.1 mmol/L and 0.5 mmol/L); Meanwhile, elevated CO2 concentration obviously decreased the stomatal openness of annual ryegrass, and made the spatial distribution pattern of stomata more regular when plants were grown at the phosphorus level of 0.06 mmol/L. (2) The elevated CO2 concentration substantially enhanced the net photosynthetic rates (Pn) of annual ryegrass treated with higher phosphorus levels (0.1 mmol/L and 0.5 mmol/L), but reduced the Pn of plants subjected to lower phosphorus levels, and thus increased the water use efficiency (WUE) of annual ryegrass at high phosphorus levels. (3) The responses of chlorophyll contents to elevated CO2 concentration were different among the six phosphorus levels, and elevated CO2 concentration substantially changed the ratio of chlorophyll a/b at higher phosphorus levels. (4) The total plant biomass and allocation between aboveground and belowground were obviously changed by phosphorus deficiency, and elevated CO2 concentration featured CO2 fertilization effect on the aboveground biomass of annual ryegrass at higher phosphorus levels. These results suggested that the responses of stomatal traits and leaf gas exchange efficiency to elevated CO2 concentration were obviously asymmetry between low and high phosphorus levels. These grasses under higher phosphorus levels optimized the leaf gas exchange efficiency by increasing the stomatal density and stomatal openness as well as regulating the spatial distribution pattern of stomata, and thus plants might benefit from CO2 fertilization effect under elevated CO2 concentration. By contrast, annual ryegrass plants subjected to low phosphorus levels down-regulated the morphological traits of stoma and the regular pattern of distribution, and decreased leaf gas exchange efficiency of annual ryegrass to adapt the low phosphorus conditions under high CO2 concentration. Our results may have significant importance on further understanding the potential mechanisms of grassland ecosystem structure and function in response to elevated CO2 concentration and phosphorus deficiency under future climate change. [ABSTRACT FROM AUTHOR]

Aims: Phosphorus (P) mobility depends on the availability of water in soil, both of which are limited resources for crop production. We studied the mechanisms governing tolerance to P-deficiency and drought stress in contrasting mungbean accessions. Methods: Tolerant (IC333090 and IC507340) and sensitive (IC488526 and EC397142) mungbean accessions were grown in soil under four treatments: control (sufficient P, irrigated), P-deficiency (no P, irrigated), drought (sufficient P, irrigation withheld), combined stress (no P, irrigation withheld), followed by a 48 h recovery. Results: Drought stress reduced the relative water content and membrane stability index, affecting overall plant growth. The tolerant accessions maintained significantly higher root growth, leaf area, and biomass under combined stress (P-deficiency and drought) than the sensitive accessions, mainly due to enhanced nutrient uptake and symbiotic N2-fixation. The combined stress also increased osmolyte concentration, antioxidative compounds, and the scavenging activity of antioxidant enzymes in tolerant accessions. Recovery from drought stress significantly reduced osmolyte concentration. Transcript abundance of candidate genes related to P-deficiency and drought under individual and combined stress, was significantly higher in leaves of IC333090 than IC488526. IC333090 recovered from drought stress better than IC488526 due to the enhanced expression of stress-responsive genes. Conclusions: Physiological traits, such as the accumulation of total soluble sugars and reduced glutathione, ascorbate, and scavenging activity of antioxidant enzymes, facilitated by the differential expression of stress-responsive genes impart cross-tolerance to P-deficiency and drought stress in tolerant mungbean accessions. Hence, accession IC333090 is potential genetic stock for tolerance to drought, P-deficiency, and combined stresses. [ABSTRACT FROM AUTHOR]

Legumes are well recognized for their nutritional and health benefits as well as for their impact in the sustainability of agricultural systems, due to their ability to form a symbiosis with N2-fixing microorganisms. Nevertheless, legume N2 fixation has a high energy cost, and phosphorus (P) deficiency strongly hampers legume production, especially in low-P soils typical of most of the tropical regions. P-deficiency limits N2 fixation, since it has been described to have a strong impact on the growth and survival of both rhizobia and host plant. Legumes have evolved strategies at both morphological and physiological levels to adapt to P-deficiency. The maintenance of symbiotic N2 fixation seems to be a key aspect to assure legume productivity in low-P environments. During the last decades, physiological components and molecular players underlying P-deficiency adaptation responses have been elucidated. Hence, in order to design strategies to develop elite cultivars able to produce high-quality seeds and efficiently fix N2 under P-deficiency, it is important to understand how legumes cope with this nutritional constraint. In this review, we discuss future directions and research priorities that may lead to a better understanding of the physiological and molecular adaptations that allow the legumes to thrive under conditions of P-deficiency. [ABSTRACT FROM AUTHOR]

Nitrogen (N) and phosphorus (P) are essential macronutrients required for plant growth and development. Under N and inorganic phosphate (Pi) deficiencies, plants undergo adaptation at physiological, morphological, and transcriptional levels via modulation of endogenous signals, such as phytohormones, in an attempt to increase nutrient acquisition from the environment. Biosynthesis of brassinosteroid (BR), a class of plant hormones, has been shown to be crucial in nutrient deficiency responses in the plant model Arabidopsis. In this study, the responses of rice (Oryza sativa L.) to N and Pi deficiencies were investigated using rice seedlings grown in the presence and absence of a BR biosynthesis inhibitor, propiconazole (PPZ). Transcript levels of BR biosynthesis genes were induced by N and Pi deficiencies. PPZ-treated plants showed retarded growth in both sufficient and deficient conditions. Besides, gene expression of N- and Pi-deficiency-responsive genes was also attenuated by PPZ treatments. These results suggest that inhibition of BR biosynthesis by PPZ could restrain plant growth and adaptation in response to both N and Pi deficiencies. [ABSTRACT FROM AUTHOR]

SUMMARY: Low‐molecular‐weight organic acid (OA) extrusion by plant roots is critical for plant nutrition, tolerance to cations toxicity, and plant–microbe interactions. Therefore, methodologies for the rapid and precise quantification of OAs are necessary to be incorporated in the analysis of roots and their exudates. The spatial location of root exudates is also important to understand the molecular mechanisms directing OA production and release into the rhizosphere. Here, we report the development of two complementary methodologies for OA determination, which were employed to evaluate the effect of inorganic ortho‐phosphate (Pi) deficiency and aluminum toxicity on OA excretion by Arabidopsis roots. OA exudation by roots is considered a core response to different types of abiotic stress and for the interaction of roots with soil microbes, and for decades has been a target trait to produce plant varieties with increased capacities of Pi uptake and Al tolerance. Using targeted ultra‐performance liquid chromatography coupled with high‐resolution tandem mass spectrometry (UPLC‐HRMS/MS), we achieved the quantification of six OAs in root exudates at sub‐micromolar detection limits with an analysis time of less than 5 min per sample. We also employed targeted (MS/MS) matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to detect the spatial location of citric and malic acid with high specificity in roots and exudates. Using these methods, we studied OA exudation in response to Al toxicity and Pi deficiency in Arabidopsis seedlings overexpressing genes involved in OA excretion. Finally, we show the transferability of the MALDI‐MSI method by analyzing OA excretion in Marchantia polymorpha gemmalings subjected to Pi deficiency. [ABSTRACT FROM AUTHOR]

A field experiment was conducted during two consecutive growing seasons (2017 and 2018) to evaluate the effects of inoculations with arbuscular mycorrhizal fungi (AMF) (Funneliformis mosseae, Rhizophagus intraradices and Claroideoglomus etunicatum) and phosphorus (P) fertilization (40 kg P2O5 ha−1) on the growth, yield and P use efficiency (PUE) of two soybean (Glycine max L.) cultivars under low soil P (6 mg kg−1) condition. AMF inoculation promotes the growth of soybean to some level compared to the P fertilized plot; however, inoculation (~960 spores per 100 g of soil) of R. intraradices or F. mosseae increased the number of nodules, nodule dry weight, shoot dry weight, root dry weight, number of pods, 100-seed weight and seed yield in both TGx 1440–1E and TGx 1448–2E soybean cultivars compared to C. etunicatum and the control. The P uptake in the shoot and grain in both cultivars increased with AMF inoculations in the order R. intraradices > F. mosseae > C. etunicatum. The studies showed that the highest yield response (44.2– 45.4%) and (44.9– 46.5%) over the control was revealed by the inoculation with R. intraradices and F. mosseae inoculants, respectively, in both soybean cultivars. TGx 1448–2E variety was more tolerant to low soil P availability and had higher root nodulation, seed yield and PUE than TGx 1448–2E variety. The results confirm functional variation among the three AMF isolates tested, which is crucial in establishing potential formulation of AMF inoculants to enhance soybean productivity in P-deficient soils. [ABSTRACT FROM AUTHOR]

The reliable sampling of root exudates in soil-grown plants is experimentally challenging. This study aimed at developing a citrate sampling and mapping technique with millimetre-resolution using DGT (diffusive gradients in thin films) ZrOH-binding gels. Citrate adsorption kinetics, DGT capacity, and stability of ZrOH gels were evaluated. ZrOH gels were applied to generate 2D maps of citrate exuded by white lupin roots grown in a rhizotron in a phosphorus-deficient soil. Citrate was adsorbed quantitatively and rapidly by the ZrOH gels; these gels can be stored after sampling for several weeks prior to analysis. The DGT capacity of the ZrOH gel for citrate depends on the ionic strength and the pH of the soil solution, but was suitable for citrate sampling. We generated for the first time 2D citrate maps of rhizotron-grown plants at a millimetre resolution to measure an illustrated plant response to phosphorus fertilization, demonstrating that DGT-based citrate sampling is suitable for studying root exudation in soil environments, at high spatial resolution. The change of binding material would also allow sampling of other exudate classes and exudation profiles of entire root systems. These aspects are crucial in cultivar breeding and selection. [ABSTRACT FROM AUTHOR]

Phosphorus (P) deficiency and aluminium toxicity often coexist and are the major constraints hampering plant growth in acidic soils. Plants have evolved several strategies to cope with these adverse environments, including the recruitment of beneficial microbes, especially mycorrhizal fungi. By employing microscopic observation, histochemical staining, and UPLC-MS/MS techniques, we analyzed the aluminium deposition and cell viability of root, symbiotic process with ECM fungus Suillus bovinus , as well as the metabolic adjustments in Pinus massoniana under low P and/or acidic aluminium conditions. The formation process of mycorrhizae between P. massoniana and S. bovinus was not affected by low P and acidic aluminium treatments, but low P postponed the development of mantle and Hartig nets. The colonization rate increased in the presence of acidic aluminium, and S. bovinus inoculation improved root cell viability and promoted the growth of P. massoniana under low P and/or acidic aluminium conditions. The metabolic responses of nonmycorrhizal and mycorrhizal P. massoniana to low P and/or acidic aluminium were different. Low P and/or acidic aluminium significantly increased the accumulation of phenolic acids and altered starch and sucrose metabolism in roots of nonmycorrhizal P. massoniana. However, for mycorrhizal P. massoniana, low P and/or acidic aluminium treatments increased the organic acids content of shared differentially accumulated metabolites (DAMs). Furthermore, acidic aluminium mainly altered arginine and proline metabolism, and phenylalanine metabolism was affected under low P conditions, linoleic acid metabolism was changed under the combined treatment of low P and acidic aluminium in mycorrhizal P. massoniana. These findings enhance our comprehension of how ECM fungi assist P. massoniana in coping with P deficiency and aluminium toxicity in acidic environments and provide a theoretical basis for ECM fungal application during seedling cultivation in acidic soils. • ECM promoted Pinus massoniana growth under low P and/or Al stresses. • Low P and/or Al stresses hardly affected ECM formation, whereas low P impeded Hartig net development. • Root metabolic adaptations to low P and / or Al stresses were further altered by mycorrhization. [ABSTRACT FROM AUTHOR]

While it is widely recognized that hydrogen sulfide (H 2 S) promotes plant stress tolerance, the precise processes through which H 2 S modulates this process remains unclear. The processes by which H 2 S promotes phosphorus deficiency (PD) and salinity stress (SS) tolerance, simulated individually or together, were examined in this study. The adverse impacts on plant biomass, total chlorophyll and chlorophyll fluorescence were more pronounced with joint occurrence of PD and SS than with individual application. Malondialdehyde (MDA), hydrogen peroxide (H 2 O 2), and electrolyte leakage (EL) levels in plant leaves were higher in plants exposed to joint stresses than in plants grown under an individual stress. When plants were exposed to a single stress as opposed to both stressors, sodium hydrosulfide (NaHS) treatment more efficiently decreased EL, MDA, and H 2 O 2 concentrations. Superoxide dismutase, peroxidase, glutathione reductase and ascorbate peroxidase activities were increased by SS alone or in conjunction with PD, whereas catalase activity decreased significantly. The favorable impact of NaHS on all the evaluated attributes was reversed by supplementation with 0.2 mM hypotaurine (HT), a H 2 S scavenger. Overall, the unfavorable effects caused to NaHS-supplied plants by a single stress were less severe compared with those caused by the combined administration of both stressors. • Salinity stress (SS) and phosphorus deficiency (PD) lowered plant growth and led to oxidative stress. • The detrimental effect of combined application of SS and PD was more marked on plant growth than their individual application. • NaHS, a donor of H 2 S, reduced oxidative stress and altered antioxidant enzymes' activities under SS or PD. • NaHS reduced Na+ and increased K+ contents under SS or SS + PD. • Hypotaurine, a H 2 S scavenger, reversed the positive effect of NaHS on plant tolerance to SS and PD. [ABSTRACT FROM AUTHOR]

Phosphorus (P), an essential macronutrient for all living organisms, is required in large amounts for the growth and development of plants. Although total soil P level is high, P bioavailability to plants is suboptimal in most soils because of high fixation rates into inorganic and organic insoluble complexes. Hence, plants are highly dependent on mechanisms that allow them to adapt to low‐phosphate stress and/or achieve suitable levels of soluble P on the root surface. In this regard, the rhizospheric microbiota plays a key role in facilitating P nutrition and has long been recognised for their potential use as an environmental‐friendly alternative to chemical P fertilisation. Herein, we outline the advances in the identification of phosphate solubilising bacteria and phosphate mineralising bacteria, collectively known as phosphobacteria, and their role in rendering P accessible to plants. We review and discuss research progress related to the introduction of phosphobacteria and/or P‐mineralising enzymes into soil, as well as plant transformation with bacterial genes that encode such enzymes, as strategies to improve plant growth and P nutrition. We also provide an overview of studies about the impact of variations in soil P levels on the structure of soil and rhizospheric microbial communities and the potential consequences of such perturbations on plant growth. Finally, we discuss possible directions for future research to optimise the efficiency of biofertilisation strategies based on the use of phosphobacteria. [ABSTRACT FROM AUTHOR]

Upland rice production on acid, weathered soils is often constrained by phosphorus (P) deficiency and aluminium toxicity. Farmyard manure application (FYM) can sharply enhance yields and agronomic P fertilizer (TSP) efficiency under such abiotic stresses. We tested the hypothesis that rice genotypes differ in aluminium tolerance and in the extent of using organic P, offering distinct benefits under TSP‐FYM combinations. Multiple field trials were conducted in the uplands of Madagascar, with factorial combinations of six genotypes, amendments of FYM (at a rate of 17–25 kg P ha−1 vs. a zero control) and TSP application (40 kg P ha−1 vs. a zero control), with blanket N&K additions. Rice grain yields reached a maximum of 6 t/ha after three years of TSP + FYM application, with an average of 3.2 t/ha over the years. Grain yields were about 1.2 t/ha for FYM only and about 1.5 t/ha for TSP only while crops failed under zero P input. Genotypic effects on rice yields were much smaller than the large effects of FYM, TSP or its combination. Application of FYM increased soil pH and CaCl2‐extractable P while decreasing CaCl2‐extractable aluminium. An additional liming trial indicated that the beneficial effects of FYM over TSP relate to liming effects. The FYM application lowers aluminium toxicity which overrules potential effects of organic P supply. Hence, genotypic ranking of yields and agronomic efficiency was inconsistent, without superior genotypes under FYM vs. TSP. However, Chomrong Dhan and FOFIFA 172 generally displayed superior yields. Chomrong Dhan is found to be more sensitive to aluminium toxicity whereas FOFIFA 172 is less performant under low P input. Aluminium tolerance should be considered when developing rice genotypes for high P efficiency in weathered soils. [ABSTRACT FROM AUTHOR]

Phosphorus (P) deficiency is a critical environmental constraint that affects the growth and development of several legume crops that are usually cultivated in semi-arid regions and marginal areas. P-deficiency is known to be a significant limitation for symbiotic nitrogen fixation (SNF), and variability in SNF is strongly interlinked with the concentrations of inorganic phosphate (Pi) in the nodules. To cope with P-deficiency, legumes trigger various adaptive responses, including the induction and secretion of acid phosphatases (APases) and phytases, maintenance of Pi homeostasis in nodules and other organs, and improvement of oxygen consumption per unit of nodule mass. While the induction of phytases is a universal response to P-deficiency in higher plants, the physiological role of these enzymes in nodules of N2-fixing legume is crucial but still not fully understood. Understanding the role of APases and phytases activities in response to environmental constraints may be important in developing strategies to improve the tolerance of the nodulated legume to low-P availability. In this review, we summarize and discuss recent advances in the understanding of the expression of phytases within the nodules of legumes under P-deficiency and address whether this expression might influence the nodule respiration and contribute to adaptation of N2 fixing legumes to low-P environments. Finally, we will provide perspectives on future directions for research in this field. [ABSTRACT FROM AUTHOR]

Background: Phosphorus (P) deficiency limits crop production worldwide. Crops differ in their ability to acquire and utilise the P available. The aim of this study was to determine root traits (root exudates, root system architecture (RSA), tissue-specific allocation of P, and gene expression in roots) that (a) play a role in P-use efficiency and (b) contribute to large shoot zinc (Zn) concentration in Brassica oleracea. Results: Two B. oleracea accessions (var. sabellica C6, a kale, and var. italica F103, a broccoli) were grown in a hydroponic system or in a high-throughput-root phenotyping (HTRP) system where they received Low P (0.025 mM) or High P (0.25 mM) supply for 2 weeks. In hydroponics, root and shoot P and Zn concentrations were measured, root exudates were profiled using both Fourier-Transform-Infrared spectroscopy and gas-chromatography-mass spectrometry and previously published RNAseq data from roots was re-examined. In HTRP experiments, RSA (main and lateral root number and lateral root length) was assessed and the tissue-specific distribution of P was determined using micro-particle-induced-X-ray emission. The C6 accession had greater root and shoot biomass than the F103 accession, but the latter had a larger shoot P concentration than the C6 accession, regardless of the P supply in the hydroponic system. The F103 accession had a larger shoot Zn concentration than the C6 accession in the High P treatment. Although the F103 accession had a larger number of lateral roots, which were also longer than in the C6 accession, the C6 accession released a larger quantity and number of polar compounds than the F103 accession. A larger number of P-responsive genes were found in the Low P treatment in roots of the F103 accession than in roots of the C6 accession. Expression of genes linked with "phosphate starvation" was up-regulated, while those linked with iron homeostasis were down-regulated in the Low P treatment. Conclusions: The results illustrate large within-species variability in root acclimatory responses to P supply in the composition of root exudates, RSA and gene expression, but not in P distribution in root cross sections, enabling P sufficiency in the two B. oleracea accessions studied. [ABSTRACT FROM AUTHOR]

The relative importance of intraspecific trait variation (rITV) for functional diversity (FD) in plant communities is increasingly apparent, but the influence of abiotic factors on the balance between intraspecific and interspecific effects in contrasting environments is uncertain. Drawing on a novel conceptual and analytic framework, we quantified rITV as the ratio of FD associated with between‐population ITV (Intra_FD) and the interspecific variation (Inter_FD) due to species turnover across sites.We predicted that rITV would increase with environmental harshness as a result of decreasing interspecific variation and concomitant increases in between‐population ITV. We empirically tested this prediction in a comparison of rITV for five traits (mature plant height, SLA, leaf dry matter content and the foliar concentrations of nitrogen and phosphorus (P)) characterizing species in Tibetan alpine meadow communities from contrasting environmental regimes.We found that across sites: (a) rITV for all five traits increased with environmental harshness not only through decreasing Inter_FD but also through increasing Intra_FD; (b) increases in rITV were mostly attributable to declines in soil resources, especially soil P, with lower soil P significantly associated with lower Inter_FD but higher Intra_FD for most traits; and (c) although neither Intra_FD nor Inter_FD was significantly impacted by species richness for any traits, a higher rITV for SLA was significantly associated with low species richness.Taken together, these results support our hypothesis that the functional significance of ITV in plant communities increases with environmental harshness. Moreover, in the Tibetan alpine meadows we studied, the opposing intraspecific and interspecific responses along a gradient of P availability appear to act as a buffering mechanism stabilizing the functional structure of communities on P deficient soils. Our novel conceptual and analytical framework provides a template for evaluating the generality of this favourable mismatch between intraspecific and interspecific responses in FD along environmental gradients. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Oil tea (Camellia oleifera Abel.) is an important edible oil tree mainly grown in acidic soils, whose growth and yield can be severely limited due to soil aluminum (Al) toxicity and phosphorus (P) deficiency. In this study, we investigated the physiological and metabolic responses of oil tea to Al and P treatment for an 8-week duration. Al reduced root length, root volume, and plant biomass, while P addition alleviated the effects of Al toxicity. P addition increased P content and reduced Al accumulation in roots. The profiles of 58 metabolites were significantly changed in roots of oil tea seedlings. Al toxicity increased various amino acids, but decreased many kinds of organic acids and carbohydrates. Interestingly, P addition reduced the amino acids accumulation which were induced by Al toxicity, while only a few organic acids changed under P supply. Most carbohydrates, including sucrose and glucose, significantly increased with P addition under Al toxicity. Results indicated that Al toxicity increased the accumulation of amino acids and reduced the accumulation of organic acids and carbohydrates, while the addition of P promoted root growth by alleviating the inhibition of protein synthesis and increasing carbohydrates content. However, P addition did not increase the organic acids content in roots. • Physiological and metabolic responses of oil tea to Al and P were investigated. • Al stress increased amino acids and decreased organic acids and carbohydrates. • P addition decreased amino acids accumulation caused by Al toxicity. • Organic acid metabolism may not be the main function of P in alleviating Al toxicity. • P alleviated Al toxicity by increasing carbohydrates, which promoted root growth. [ABSTRACT FROM AUTHOR]