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Bone marrow-derived mesenchymal stem cells (BMSCs) are capable of developing into osteoblastic cell lines in vitro and regenerating bone tissue in vivo, and they are considered to be a reliable source for bone regenerative medicine. In recent years, studies have shown that the immune microenvironment is important for osteogenesis, in which macrophages are an important component of innate immunity and coordinate with stem cells. Metformin (Met), a hypoglycemic drug that exerts a powerful effect on metabolic signaling, has been shown to modulate inflammatory responses and osteogenic activity. However, whether metformin modulates macrophage polarization and subsequently affects osteogenesis remains to be elucidated. In the present study, we investigated the potential immunomodulatory capacity of metformin on macrophage inflammatory responses and phenotypic switching, and the subsequent effects on osteogenic differentiation of BMSCs. Flow cytometry and qPCR were used to study the effects of metformin on macrophage phenotypic regulation. qPCR, ALP, ARS and calcium content measurement and ALP activity assay were used to determine the effects of macrophage-secreted activators on the osteogenic differentiation of BMSCs. Our study demonstrates that metformin can improve the immune microenvironment by modulating macrophage polarization towards an anti-inflammatory phenotype, promoting an increase in a range of anti-inflammatory factors and inhibiting pro-inflammatory factors. This was characterized by increased expression of IL-10 and CD206, Arg-1 and decreased expression of IL-1β, TNF-α, IL-6 and iNOS. In addition, metformin-modulated macrophage-conditioned medium promoted osteogenic differentiation of BMSCs, increased the expression levels of genes (ALP, Runx-2, OCN, and Col-1), enhanced ALP activity, and significantly formed mineralized nodules. In conclusion, our new study elucidates that metformin can promote osteogenic differentiation of BMSCs by modulating macrophage phenotype and thereby. [ABSTRACT FROM AUTHOR]

Aims: Enhancing crop yields is a contemporary challenge of the modern world, and selenium (Se) has been shown to improve plant health against various abiotic stressors. This study aimed to evaluate the influence of Se on the biosynthesis of photosynthetic pigments, nitrogen metabolism, antioxidant metabolism, flavonoid synthesis and nodulation of cowpea plants. Methods: We carried out a soil experiment with five Se application rates (0, 7.5, 15, 30, and 45 µg kg−1) and a hydroponics experiment with four Se concentrations (0, 5, 10, and 15 µmol L−1). Results: Both experiments revealed hormetic-like responses of cowpea plants to Se, at both molecular and whole-plant levels. Se dose-dependently increased the synthesis of chlorophylls, carotenoids and pheophytin as well as the efficiency of enzymatic antioxidant metabolism by decreasing MDA levels and increasing CAT and APX activity. Selenium also enhanced nitrate reductase activity, resulting in greater biosynthesis of amino acids and proteins in the leaves. However, the dose responses were not identical in the two experiments. Hormetic-like biphasic responses were uniquely revealed for daidzein, genistein, and kaempferol in the hydroponics experiment. Selenium also enhanced the number of nodules in roots, which generated increases in the production of ureides and greater production of shoot dry weight in both experiments. Low rates of Se stimulated the translocation of allantoic acid from nodules to leaves. Conclusions: This study adds new insights regarding Se effect on antioxidant and nitrogen metabolism, photosynthetic pigments and nodulation, which can increase cowpea yield. [ABSTRACT FROM AUTHOR]

Background and aims: While the effects of fertilizer nitrogen (N) on N fixation in soybean nodules lead to both local inhibition and systemic regulation, the specific mechanism is not clear. This study aimed to elucidate the mechanism by which systemic N regulation affects soybean root growth and N fixation. Methods: Dual-root soybean plants containing unilateral nodulation were cultivated using grafting and sand culture with the addition of N-containing nutrient solution to the non-nodulated root portion and N-free nutrient solution to the nodulated portion during the VC-R1 period (28 d). The effects of N supplementation on changes in the expression of genes and proteins, as well as metabolite levels, in nodules and roots were examined, together with an evaluation of alterations in metabolic pathways in response to the indirect N supply. Results: The results demonstrated that a 28-day supply of N to non-nodulated part of the root reduced nodulation while promoting the growth of the root system on the nodulation side. A comparative evaluation of the soybean plants cultivated with and without N supplementation revealed that N promoted the synthesis of signaling compounds, such as asparagine and trehalose, in nodules and inhibited flavonoid-associated metabolic pathways. Starch syntheis in nodules under long-term high-N was inhibited while the metabolism of organic acids was enhanced. Long-term indirect N supply also influenced pathways associated with amino acid metabolism and phenylpropanoid biosynthesis pathway in the roots. Conclusion: The different response metabolic pathways of roots and nodules supported the different characteristics of soybean roots and nodules after indirect nitrogen supply. Additionally, the duration of nitrogen supply affects the regulatory pathway of nitrogen fixation of nodules. [ABSTRACT FROM AUTHOR]

Legumes acquire nitrogen-fixing ability by forming root nodules. Transferring this capability to more crops could reduce our reliance on nitrogen fertilizers, thereby decreasing environmental pollution and agricultural production costs. Nodule organogenesis is complex, and a comprehensive transcriptomic atlas is crucial for understanding the underlying molecular events. Here, we utilized spatial transcriptomics to investigate the development of nodules in the model legume, Lotus japonicus. Our investigation has identified the developmental trajectories of two critical regions within the nodule: the infection zone and peripheral tissues. We reveal the underlying biological processes and provide gene sets to achieve symbiosis and material exchange, two essential aspects of nodulation. Among the candidate regulatory genes, we illustrate that LjNLP3, a transcription factor belonging to the NIN-LIKE PROTEIN family, orchestrates the transition of nodules from the differentiation to maturation. In summary, our research advances our understanding of nodule organogenesis and provides valuable data for developing symbiotic nitrogen-fixing crops. Legumes develop root nodules to access nitrogen. A spatial transcriptomic analysis of Lotus japonicus uncovered key molecular mechanisms and genes involved in nodule development, promoting the creation of novel nitrogen-fixing crops. [ABSTRACT FROM AUTHOR]

Satellite nodules is a key clinical characteristic which has prognostic value of hepatocellular carcinoma (HCC). Currently, there is no gene-level predictive model for Satellite nodules in liver cancer. For the 377 HCC cases collected from the dataset of Cancer Genome Atlas (TCGA), their original pathological data were analyzed to extract information regarding satellite nodules status as well as other relevant pathological data. Then, this study employed statistical modeling for prognostic model establishment in TCGA, and validation in International Cancer Genome Consortium (ICGC) cohorts and GSE76427. Through rigorous statistical analyses, 253 differential satellite nodules-related genes (SNRGs) were identified, and four key genes related to satellite nodules and prognosis were selected to construct a prognostic model. The high-risk group predicted by our model exhibited an unfavorable overall survival (OS) outlook and demonstrated an association with adverse worse clinical characteristics such as larger tumor size, higher alpha-fetoprotein, microvascular invasion and advanced stage. Moreover, the validation of the model's prognostic value in the ICGC and GSE76427 cohorts mirrored that of the TCGA cohort. Besides, the high-risk group also showed higher levels of resting Dendritic cells, M0 macrophages infiltration, alongside decreased levels of CD8+ T cells and γδT cells infiltration. The prognostic model based on SNRGs can reliability predict the OS of HCC and is likely to have predictive value of immunotherapy for HCC. [ABSTRACT FROM AUTHOR]

Aims: Inoculation with climate-adapted rhizobia is able to increase legume productivity in drought-prone regions of Sub-Saharan Africa. Enhanced nodulation might additionally affect plant-soil interactions and control rhizosphere carbon (C) and nitrogen (N) pools. Methods: We investigated inoculation effects on nodulation and biological N2 fixation (BNF) of Vigna unguiculata and consequent effects on C and N pools in two Namibian soils. Three treatments (Bradyrhizobium sp.1–7 inoculant, non-inoculated, N-fertilised with 50 kg N ha−1) were applied in rhizoboxes at 45% and 20% maximum water holding capacity. Nodule development was photo-documented, and rhizobia-DNA sequences were identified. BNF was assessed by δ15N enrichment, and organic C and N pools were analysed in bulk and root adherent soil. Results: Plant growth initially enhanced mineral N losses from the rhizosphere at flowering stage (6 weeks growth), but led to a re-increase of N, and organic C contents after ripening (10 weeks). Inoculation had no effect on nodulation and soil C and N pools, indicating that both soils contained sufficient indigenous rhizobia to allow effective nodulation. However, the inoculant strain was more competitive in establishing itself in the root nodules, depending on the local conditions, showing a need for regional adjustment of inoculation strategies. Conclusion: Water stress was the main limitation for nodulation and, in combination with soil type, substantially affected rhizosphere and bulk soil C and N contents. The temporally enhanced rhizodeposition after ripening could be able to maintain soil C and N pools after legume cultivation. [ABSTRACT FROM AUTHOR]

Purpose: The increase in frequency of freeze–thaw episodes with the diminution of snow cover protection due to climate change compromises the winter survival of alfalfa (Medicago sativa L.). Symbiosis with cold-tolerant rhizobial strains can improve the ability of alfalfa to survive and grow under stressful conditions. Methods: Six strains of Sinorhizobium (Ensifer) meliloti were tested in combination with two alfalfa populations bred to differ in their levels of freezing tolerance. Plants of each different combination were grown for eight weeks in a growth chamber before being exposed to temperatures promoting their acclimation to cold. Plants were then exposed to a freezing stress (-11ºC) and regrown for three weeks. Shoot, root and nodule biomass were measured before cold acclimation and three weeks after the freezing stress. Results: After freezing stress, the alfalfa population A-TF7 had shoot and root biomasses that were respectively 19% and 15% larger than cultivar A-TF0. Alfalfa plants inoculated with strain NRG34 showed both a larger shoot biomass and a higher nodule dry weight than plants inoculated with any other strains. Assessment of freezing damages on nodules showed that plants inoculated with NRG34 had the largest proportion of undamaged nodules or of nodules with a regeneration zone. Conclusion: This study shows for the first time a relationship between nodule and shoot regrowth after a freezing stress, the latter being linked with the proportion of nodules showing less freezing damage. Our results demonstrated that both the choice of alfalfa populations and S. meliloti strains adapted to stress are complementary to increasing alfalfa persistence. [ABSTRACT FROM AUTHOR]

Biochars produced from different feedstocks and at different pyrolysis temperatures may have various chemical and physical properties, affecting their potential use as alternative microbial carrier materials. In this study, biochars were produced from pine wood and oak feedstocks at various temperatures (400°C, 500°C, 600°C, 700°C and 800°C), characterized, and assessed for their potential as carriers for Bradyrhizobium japonicum (CB1809) strain. The biochars were then stored at two different storage temperatures (28°C and 38°C) for up to 90 days. Furthermore, the study also explored the role of potentially ideal carriers as inoculants in the growth of Glycine max L. (soybean) under different moisture levels i.e., 55% water holding capacity (WHC) (D0), 30% WHC (D1) and, 15% WHC (D2) using a mixture of 50% garden soil and 50% sand. The results were compared to a control group (without inoculants) and a peat inoculant. Among all the materials derived from pine wood and oak, pine wood biochar pyrolyzed at 400℃ (P-BC400) exhibited the highest CFU count, with values of 10.34 and 9.74 Log 10 CFU g− 1 after 90 days of storage at 28℃ and 38℃, respectively. This was notably higher compared to other biochars and peat carriers. Significant (p < 0.05) increases in plant properties: shoot and root dry biomass (174% and 367%), shoot and root length (89% and 85%), number of leaves (71%), membrane stability index (27%), relative water content (26%), and total chlorophyll (140%) were observed in plants treated with P-BC400 carrier inoculant compared to the control at D2; however, lower enrichment of δ13C (37%) and δ15N (108%) with highest number of root nodules (8.3 ± 1.26) and nitrogenase activity (0.869 ± 0.04) were observed under D2, as evident through PCA analysis, showing more nitrogen (N) fixation and photosynthetic activity. Overall, this experiment concluded that biochar pyrolyzed at lower temperatures, especially P-BC400, was the most suitable candidate for rhizobial inoculum and promoted soybean growth. [ABSTRACT FROM AUTHOR]

Bacterial strains isolated from root nodules of the legume plant Hedysarum arcticum B. Fedtsch growing on Samoylov Island in the Lena River delta (Arctic zone of Yakutia) were assigned to the genera Rhizobium (family Rhizobiaceae) and Mesorhizobium (Phyllobacteriaceae) of the order Hyphomicrobiales (class Alphaproteobacteria) according to the rrs gene sequencing data. According to phylogenetic analysis of concatemers of the atpD, dnaK, gyrB, and rpoB genes, the strains belonged to the species Rhizobium giardinii and Mesorhizobium norvegicum. The strains were shown to be facultative psychrotrophs growing at 5 and 28°C. These microsymbionts are promising for further study of their symbiotic efficiency regarding other forage legume species, with an aim to establish highly productive agrophytocenoses in the Far North. [ABSTRACT FROM AUTHOR]

Pre-proenkephalin 1 (Penk1) is a pro-neuropeptide that belongs to the typical opioid peptide's family, having analgesic properties. We previously found Penk1 to be the most downregulated gene in a whole gene profiling analysis performed in osteoblasts subjected to microgravity as a model of mechanical unloading. In this work, Penk1 downregulation was confirmed in the bones of two in vivo models of mechanical unloading: tail-suspended and botulinum toxin A (botox)-injected mice. Consistently, in the sera from healthy volunteers subjected to bed rest, we observed an inverse correlation between PENK1 and bed rest duration. These results prompted us to investigate a role for this factor in bone. Penk1 was highly expressed in mouse bone, but its global deletion failed to impact bone metabolism in vivo. Indeed, Penk1 knock out (Penk1−/−) mice did not show an overt bone phenotype compared to the WT littermates. Conversely, in vitro Penk1 gene expression progressively increased during osteoblast differentiation and its transient silencing in mature osteoblasts by siRNAs upregulated the transcription of the Sost1 gene encoding sclerostin, and decreased Wnt3a and Col1a1 mRNAs, suggesting an altered osteoblast activity due to an impairment of the Wnt pathway. In line with this, osteoblasts treated with the Penk1 encoded peptide, Met-enkephalin, showed an increase of Osx and Col1a1 mRNAs and enhanced nodule mineralization. Interestingly, primary osteoblasts isolated from Penk1−/− mice showed lower metabolic activity, ALP activity, and nodule mineralization, as well as a lower number of CFU-F compared to osteoblasts isolated from WT mice, suggesting that, unlike the transient inhibition, the chronic Penk1 deletion affects both osteoblast differentiation and activity. Taken together, these results highlight a role for Penk1 in the regulation of the response of the bone to mechanical unloading, potentially acting on osteoblast differentiation and activity in a cell-autonomous manner. [ABSTRACT FROM AUTHOR]

Class I KNOTTED-like homeobox (KNOXI) genes are parts of the regulatory network that control the evolutionary diversification of leaf morphology. Their specific spatiotemporal expression patterns in developing leaves correlate with the degrees of leaf complexity between simple-leafed and compound-leafed species. However, KNOXI genes are not involved in compound leaf formation in several legume species. Here, we identify a pathway for dual repression of MtKNOXI function in Medicago truncatula. PINNATE-LIKE PENTAFOLIATA1 (PINNA1) represses the expression of MtKNOXI, while PINNA1 interacts with MtKNOXI and sequesters it to the cytoplasm. Further investigations reveal that UNUSUAL FLORAL ORGANS (MtUFO) is the direct target of MtKNOXI, and mediates the transition from trifoliate to pinnate-like pentafoliate leaves. These data suggest a new layer of regulation for morphological diversity in compound-leafed species, in which the conserved regulators of floral development, MtUFO, and leaf development, MtKNOXI, are involved in variation of pinnate-like compound leaves in M. truncatula. This study reveals a pathway in which the transformation of trifoliate leaves into pinnate-like pentafoliate leaves is regulated by the conserved regulators of floral development (MtUFO) and leaf development (MtKNOXI) in M. truncatula. [ABSTRACT FROM AUTHOR]

Conserved motifs (peptide patterns) determining the elicitor properties of plant-pathogenic bacteria were identified in the amino acid sequences of the flagellins of phytopathogenic, associative, and root nodule microflora. In plant-growth-promoting rhizobacteria (PGPR), analogs of one (flg22) out of two (flg22 and flgII-28) specific peptides characteristic of pathogens were found. Instead of glycine G18, characteristic of an elicitor, tyrosine Y18 was identified in flg22 analogs of most PGPR, which prevents actuation of the phytoimmunity mechanism against PGPR. Molecular docking with the AlphaFold software package demonstrated significance of the interaction between the plant receptor FLS2 and the canonical peptide flg22 and its analogs from a plant pathogen and an Azospirillum bacterium. However, in the case of the FLS3 plant receptor, only its interactions with the canonical peptide flgII-28 and its analog from the plant pathogen were statistically significant. [ABSTRACT FROM AUTHOR]

Aims: In Morocco, the Zaida abandoned mine is a major source of metallic trace elements that are harmful to the environment and human health. With the aim to use the heavy metal tolerant legume tree Robinia pseudoacacia in the phytostabilization of this mine's tailings, we isolated and characterized its indigenous microsymbionts, and tested their effects on the plant growth under high Pb-acetate concentrations. Methods: Thus, 27 bacteria were isolated from nodules of the plant grown in the Zaida abandoned mine tailings, and we examined their tolerance to high concentrations of Pb-acetate in-vitro. Four strains were then selected for symbiotic, molecular, and phenotypic analyses, and we analyzed the effect of inoculation on the plant growth parameters under increasing Pb-acetate concentrations (in-vivo). Results: The isolated strains tolerate high lead concentrations. The Phylogenetic analyses of 16 S rRNA, five housekeeping genes (MLSA), and three symbiotic genes showed the affiliation of the strains with Ensifer meliloti sv. rigiduloides and E. kummerowiae sv. meliloti. Representative strains of both symbiovars tolerate 1100 µg ml− 1 Pb-acetate in-vitro and nodulate R. pseudoacacia even under 1200 µg ml− 1 of Pb-acetate. In all tests, the plant proline content increased as a response mechanism to increasing concentrations of Pb-acetate. Inoculation experiments under high concentrations of Pb-acetate showed that both strains improved the plant growth parameters and chlorophyll content compared to controls. Conclusion: Our results show that E. meliloti sv. rigiduloides strain RPZ12 improves plant growth under Pb stress conditions more than E. kummerowiae sv. meliloti strain RPZ17. Strain RPZ12 would be an excellent inoculum to use for the phytostabilization of Zaida mine tailings. This is the first description of symbiovar meliloti in E. kummerowiae. [ABSTRACT FROM AUTHOR]

Rhizobium is well-documented for its symbiotic relationship with legume plants, where it plays a crucial role in biological nitrogen-(N)-fixation within their root nodules. However, the isolation, identification, and association of Rhizobium as a free-living diazotroph with potato plants remain relatively less explored. The present study reports the isolation and characterization of free-living Rhizobium strain from the rhizosphere of potato plants and its potential for promoting growth and N-fixation. Diazotrophic strain (TN04) was isolated from rhizosphere of potato plants on nitrogen-free media and identified on the basis of 16S rRNA gene sequence (Accession number: LN833444). TN04 strain also contained nifH gene and showed N-fixation potential (151.70 nmolmg/protein/h) through ARA activity, indicating its ability to fix atmospheric nitrogen. TN04 exhibited potential for phosphate solubilization (272.5 µg/mL) and produced indole acetic acid at concentration of 3.50 µg/mL. To assess the N-fixing ability of TN04 diazotroph, a 15N dilution experiment was conducted in pots using sterilized sand and sterilized soil under various fertilizer doses. The results of pot experiments demonstrated significant improvement in N content and growth parameters of inoculated potato plants compared to un-inoculated controls, suggesting that diazotrophic strain effectively fixed atmospheric N through isotopic dilution. Moreover, Rhizobium sp. TN04 remarkably improved plant growth and agronomic parameters under field conditions. Significant improvements were observed in N uptake, N utilization, and N use efficiency in field trails. In addition, microscopic analysis using transmission electron and confocal laser scanning microscopy provided insights into the colonization patterns of TN04 strain at the junctions between the secondary and primary roots, forming strong association with potato roots. Our study presents novel insights into the presence and interaction of Rhizobium with non-host plants, shedding light on its N-fixing capabilities in non-leguminous crops. These findings pave the way for developing strategies to explore microbiome of non-leguminous crops and exploit the N-fixation of Rhizobium in non-host crops. [ABSTRACT FROM AUTHOR]

KNOTTED-LIKE HOMEOBOX (KNOX) proteins are homeodomain containing transcription factors, and regulate many aspects of plant development through homo or heterodimerization with another group of TALE transcription factors known as BELL. In Medicago truncatula the MtKNOX3 gene is involved in nodule development. In this work, we hypothesized that MtKNOX3 involvement in the activation of cytokinin signaling during nodule development could be through heterodimerization with BELL proteins. Thereby, the expression of different BELL genes in Medicago was analyzed, and it was shown that the expression of Medtr8g078480 and Medtr8g098815 genes increases during nodule development. Besides, the Medtr8g078480 shows a co-expression pattern with MtKNOX3 at different developmental stages of nodule development. Afterward, the interaction of MtKNOX3 with the MtBELL1-2 (Medtr8g078480) protein was shown using docking, and their stability was analyzed by molecular dynamic simulation and mmpbsa methods. Moreover, the stability of MtKNOX3- Medtr8g078480 heterodimers was compared with the MtKNOX3 homodimer. [ABSTRACT FROM AUTHOR]

Exploiting the symbiotic interaction between crops and nitrogen-fixing bacteria is a simple and ecological method to promote plant growth in prospective extraterrestrial human outposts. In this study, we performed an RNA-seq analysis to investigate the adaptation of the legume symbiont Paraburkholderia phymatum STM815T to simulated microgravity (s0-g) at the transcriptome level. The results revealed a drastic effect on gene expression, with roughly 23% of P. phymatum genes being differentially regulated in s0-g. Among those, 951 genes were upregulated and 858 downregulated in the cells grown in s0-g compared to terrestrial gravity (1 g). Several genes involved in posttranslational modification, protein turnover or chaperones encoding were upregulated in s0-g, while those involved in translation, ribosomal structure and biosynthesis, motility or inorganic ions transport were downregulated. Specifically, the whole phm gene cluster, previously bioinformatically predicted to be involved in the production of a hypothetical malleobactin-like siderophore, phymabactin, was 20-fold downregulated in microgravity. By constructing a mutant strain (ΔphmJK) we confirmed that the phm gene cluster codes for the only siderophore secreted by P. phymatum as assessed by the complete lack of iron chelating activity of the P. phymatum ΔphmJK mutant on chrome azurol S (CAS) agar plates. These results not only provide a deeper understanding of the physiology of symbiotic organisms exposed to space-like conditions, but also increase our knowledge of iron acquisition mechanisms in rhizobia. [ABSTRACT FROM AUTHOR]

Anaerobic gut fungi (AGF, Neocallimastigomycota) reside in the alimentary tract of herbivores. While their presence in mammals is well documented, evidence for their occurrence in non-mammalian hosts is currently sparse. Culture-independent surveys of AGF in tortoises identified a unique community, with three novel deep-branching genera representing >90% of sequences in most samples. Representatives of all genera were successfully isolated under strict anaerobic conditions. Transcriptomics-enabled phylogenomic and molecular dating analyses indicated an ancient, deep-branching position in the AGF tree for these genera, with an evolutionary divergence time estimate of 104-112 million years ago (Mya). Such estimates push the establishment of animal-Neocallimastigomycota symbiosis from the late to the early Cretaceous. Further, tortoise-associated isolates (T-AGF) exhibited limited capacity for plant polysaccharides metabolism and lacked genes encoding several carbohydrate-active enzyme (CAZyme) families. Finally, we demonstrate that the observed curtailed degradation capacities and reduced CAZyme repertoire is driven by the paucity of horizontal gene transfer (HGT) in T-AGF genomes, compared to their mammalian counterparts. This reduced capacity was reflected in an altered cellulosomal production capacity in T-AGF. Our findings provide insights into the phylogenetic diversity, ecological distribution, evolutionary history, evolution of fungal-host nutritional symbiosis, and dynamics of genes acquisition in Neocallimastigomycota. Here, Pratt et al identify a community of deep-branching anaerobic fungi in tortoise feces. Multiple characteristics underpinning their success in tortoise, as opposed to scarcity in mammalian alimentary tracts, are presented. [ABSTRACT FROM AUTHOR]

Background and aims: Invasive plants often alter soil abiotic and biotic conditions which can benefit their own growth while harming native species. The impacts on native species may persist as legacy effects after the invasive species has been controlled and removed. This study focused on the Critically Endangered Cumberland Plain Woodland (CPW) vegetation in Australia, where we examined the soil impacts, and their associated legacy effects, associated with the invasion of African olive (Olea europaea subsp. cuspidata). Methods: Seedlings of O. europaea subsp. cuspidata and two native legume species, Acacia implexa and Indigofera australis, were grown in different sterilised and unsterilised soils: uninvaded CPW soil, restored CPW soil where O. europaea subsp. cuspidata was removed approximately 20 years ago, and soil from sites still under O. europaea subsp. cuspidata invasion. We characterised nitrogen-fixing rhizobia in the root nodules of seedlings of the two legumes using next-generation sequencing (NGS) barcoding. Results: Olea europaea subsp. cuspidata did not appear to condition the soil to favour its own growth and grew best in uninvaded CPW soil. The performance of both native legume species, however, was negatively impacted when grown in sterilised and unsterilised invaded soils, relative to their growth in CPW and restored soils. The soils from invaded sites affected the associations between both legume species and their rhizobium mutualists. Nodulation was higher in CPW and restored soils than in invaded soils, indicating that the availability of rhizobia was negatively impacted by O. europaea subsp. cuspidata. This was confirmed by a negative link between nodulation and the abundance of rhizobia that were characteristic of invaded soils. Conclusion: Our findings demonstrate that O. europaea subsp. cuspidata invasion affects the availability of microbial mutualists for native legumes in the CPW. The soil conditions created by O. europaea subsp. cuspidata do not benefit its own performance and these impacts do not persist as legacy effects 20 years after the removal of the invader. [ABSTRACT FROM AUTHOR]

Mycorrhizal fungi form symbiotic relationships with most terrestrial plants. Soil nutrients affect the mycorrhizal symbiotic formation, further determine plant growth. However, little is known on the role of mycorrhiza in response of host plant growth to nutritional additions in natural ecosystem. A new database was established including the index of plant growth and their mycorrhizal status based on a global database of interactive effects of nitrogen (N) and phosphorus (P) additions on plant growth. We examined effects of mycorrhizal strategy on the responses of plant growth to N or P addition. We found that plant growth was closely related to mycorrhizal strategies. N addition increased 35% aboveground biomass (AGB) of host plants associated with arbuscular mycorrhiza (AM), whereas decreased it by 9% in plants non-associated with AM (nonAM). P addition or NP addition all increased AGB regardless of mycorrhizal type, but the effect of nonAM plants was stronger than that of AM plants. Structural equation modelling (SEM) analysis showed that N addition had an positive effect on leaf N:P ratios through affecting leaf N of AM plants (r = 0.25) and nonAM plants (r = 0.33) whereas P addition had an negative effect on leaf N:P ratios through affecting leaf P of AM plants (r = 0.29) and nonAM plants (r = 0.45). Our results highlighted the biomass production of plants was controlled mainly by P addition and AM increased the accumulation of AGB by promoting plant P uptake. Moreover, AMF have different functions depending on the nutritional conditions, further regulated plant growth. [ABSTRACT FROM AUTHOR]

Microglia nodules (HLA-DR+ cell clusters) are associated with brain pathology. In this post-mortem study, we investigated whether they represent the first stage of multiple sclerosis (MS) lesion formation. We show that microglia nodules are associated with more severe MS pathology. Compared to microglia nodules in stroke, those in MS show enhanced expression of genes previously found upregulated in MS lesions. Furthermore, genes associated with lipid metabolism, presence of T and B cells, production of immunoglobulins and cytokines, activation of the complement cascade, and metabolic stress are upregulated in microglia nodules in MS. Compared to stroke, they more frequently phagocytose oxidized phospholipids and possess a more tubular mitochondrial network. Strikingly, in MS, some microglia nodules encapsulate partially demyelinated axons. Taken together, we propose that activation of microglia nodules in MS by cytokines and immunoglobulins, together with phagocytosis of oxidized phospholipids, may lead to a microglia phenotype prone to MS lesion formation. Microglia nodules are associated with brain pathology. Here, the authors show demyelination in microglia nodules in multiple sclerosis (MS), likely due to oxidized phospholipid phagocytosis and immune activation, suggesting that nodules could be involved in MS lesion formation. [ABSTRACT FROM AUTHOR]

The symbiogenetic origin of eukaryotes with mitochondria is considered a major evolutionary transition. The initial interactions and conditions of symbiosis, along with the phylogenetic affinity of the host, are widely debated. Here, we focus on a possible evolutionary path toward an association of individuals of two species based on unidirectional syntrophy. With the backing of a theoretical model, we hypothesize that the first step in the evolution of such symbiosis could be the appearance of a linking structure on the symbiont's membrane, using which it forms an ectocommensalism with its host. We consider a commensalistic model based on the syntrophy hypothesis in the framework of coevolutionary dynamics and mutant invasion into a monomorphic resident system (evolutionary substitution). We investigate the ecological and evolutionary stability of the consortium (or symbiotic merger), with vertical transmissions playing a crucial role. The impact of the 'effectiveness of vertical transmission' on the dynamics is also analyzed. We find that the transmission of symbionts and the additional costs incurred by the mutant determine the conditions of fixation of the consortia. Additionally, we observe that small and highly metabolically active symbionts are likely to form the consortia. [ABSTRACT FROM AUTHOR]

The effect of surface growth-controlling additives, such as glue and thiourea, as well as the influencing parameters in the copper electrorefining process, such as electrolyte temperature, flow rate, concentration of dissolved copper and sulfuric acid, and TSS particles on nodule formation in the copper cathode, was investigated. The results of EDS/SEM and XRD showed that compounds such as As2O(SO4)2 and Cu3(AsO4)2, and BaSO4, which were present in the examined sludge, were also present in the roots of nodules. Increasing glue concentration to 135 g/ton caused a decrease in the percentage of nodules on the cathode surface. This, along with the chlorine ion control in the range of 0.03–0.035 g/L, had a promising effect in reducing the nodules on the cathode surface. Also, increasing the concentration of thiourea caused fine graining of the cathode structure.The optimal conditions for production of uniform cathode surface and the elimination of nodules were electrolyte flow rate 30 L/min, electrolyte temperature 61 ± 2°C, concentration of dissolved copper in the range of 45–43 g/L, concentration of 180 g/L sulfuric acid and < 50 ppm TSS particles. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) trigger beneficial effects on their hosts, but it is unknown how plants modulate their defense responses during root colonization of AMF and the symbiotic benefits are initiated. The purpose of this study was to analyze the root mycorrhizal colonization process of trifoliate orange and the responsive patterns of plant growth, root peroxide hydrogen (H2O2), antioxidant enzymes and their encoding gene expression, and sugar, lipid and phosphate transporter protein gene expression at 7‒56 days of inoculation (doi) with Funneliformis mosseae (Fm). Fm developed appressoriums on the root surface at 7 doi, followed by abundant arbuscules in root cortical cells at 28 doi, intracellular vesicles at 42 doi, and root mycorrhizal colonization rate of 41.54% at 56 doi. Plant growth improvement by Fm started at 28 doi. The immune defense response of roots was initiated at 7 doi, as evidenced by the increase of H2O2 levels and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity, as well as the up-regulation of PtMn-SOD, PtCu/Zn-SOD, PtPOD, and PtCAT expression, which lasted until 14 doi. Starting at 28 doi, a sugar transporter gene (PtSWEET), a lipid transporter gene (PtSTR), and a phosphate transporter gene (PtPT6) were initiated to be up-regulated, followed by the up-regulation of PtSTR2, PtPT3, and PtPT5 at 42 doi and PtFe-SOD at 56 doi. Arbuscule formation and plant growth improvement together at 28 doi suggested that arbuscules trigger improved growth responses of host plants. This study also reveals the initiation of host immune defense response and function in early root AMF colonization. [ABSTRACT FROM AUTHOR]

Legumes have the unique ability to form symbiosis with nitrogen-fixing bacteria of the genus Rhizobium by forming special symbiotic organs called nodules. The process of symbiosis initiation and development between legumes and rhizobia is tightly controlled by a complex network of transcription factors. Control of root nodule development and infection thread formation involves the recognition of rhizobial signal molecules through specific receptors, which trigger signal transduction cascades. IPD3 and NIN transcription factors begin to act early in this process. The IPD3 transcription factor has been previously shown to regulate infection processes associated with rhizobial invasion and activate several downstream components, including NIN transcription factor. NIN, in turn, plays an important role in the control of infection process as well as in nodule organogenesis. Nevertheless, their targets in developing nodules of legumes such as Pisum sativum and Medicago truncatula remain unclear. In our study, we used chromatin immunoprecipitation combined with the next-generation sequencing (ChIP-Seq) method to identify targets of PsIPD3 and PsNIN in the Pisum sativum genome. To do this, we generated transgenic plants carrying the p35S::PsIPD3~3XFLAG::t35S and p35S::PsNIN~3XFLAG::t35S constructs using the Agrobacterium rhizogenes-mediated transformation approach. Immunoprecipitation of chromatin bound to PsIPD3~3XFLAG and PsNIN~3XFLAG proteins was performed using anti-FLAG antibodies, and libraries generated from bound chromatin were sequenced on the Illumina NovaSeq 6000 platform. Here, the methodical approaches for preparation of IPD3-targets-enriched and NIN-targets-enriched samples in pea plants using ChiP-Seq are discussed. [ABSTRACT FROM AUTHOR]

Nodule bacteria (rhizobia) represent the highly developed model for the evolutionary genetics of symbiotic microorganisms. We propose to divide these polyphyletically originated bacteria into two groups that have arisen through: a) genomic rearrangements in free-living N2-fixers (primary rhizobia originated via the phyletic evolution strategy); b) transfer of symbiotically specialized (sym) genes from rhizobia to various soil and plant-associated bacteria (secondary rhizobia originated via the reticular evolution strategy). Primary rhizobia are represented by genus Bradyrhizobium close to Rhodopsedomonas. Transformation of these phototrophic N2-fixers into plant symbionts is evidenced by transitional (ancestral) Bradyrhizobium genotypes that combine the legume nodulation with photosynthesis. A crucial stage in rhizobia evolution was represented by acquisition of the ability to produce lipochitooligosaccharide Nod factors (NFs) eliciting the nodule development. Acquisition of NF synthesis allowed the ancestral Bradyrhizobium strains to switch from autotrophy to assimilation of the plant photosynthesis products resulted in heterotrophic bradyrhizobia (e.g., B. japonicum, B. elkanii) harboring sym genes in chromosomes. The best studied secondary rhizobia are represented by the Rhizobiaceae (Rhizobium, Sinorhizobium, Neorhizobium) species in which sym genes are located in mobile plasmids or chromids. Interactions of these species with legumes may be addressed as altruistic symbiosis based on development of non-reproducible bacteroids which supply hosts with N compounds. Since the rhizobia evolution involves the "gain-and-loss" genetic strategy, constructing highly active strains for legume crop inoculation should be based on activation of positive regulators of symbiotic N2 fixation and on inactivation of its negative regulators. [ABSTRACT FROM AUTHOR]

A collection of twenty-eight strains isolated from root nodules of Astragalus inopinatus Boriss. and Astragalus umbellatus Bunge originating from the Kamchatka Peninsula (Russian Federation) was obtained for the first time. Analysis of the 16S ribosomal RNA gene sequence revealed a significant diversity of isolates belonging to 4 genera of the order Hyphomicrobiales: Mesorhizobium, Rhizobium, Bosea and Tardiphaga. The presence of phenotypically and taxonomically different strains (Bosea + Tardiphaga, Bosea + Mesorhizobium, Tardiphaga + Mesorhizobium, Bosea + Rhizobium) in some nodules of both plants was also observed. The symbiotic efficiency of strains isolated from A. inopinatus plants in the nodulation assay showed that most isolates of the genus Mesorhizobium and Rhizobium can form a nitrogen-fixing symbiosis with A. inopinatus, leading to a significant increase in plant biomass compared to the non-inoculated control. [ABSTRACT FROM AUTHOR]

Grass pea (L. sativus L.) is a widely cultivated crop worldwide, forming a symbiotic relationship with nitrogen-fixing rhizobia. Glyphosate is commonly used by farmers for weed control during agricultural processes. However, the application of this chemical herbicide negatively impacts soil fertility by affecting the nitrogen-fixing rhizobia. This study aimed to assess the effects of glyphosate on rhizobia isolated from healthy and robust Grass pea plants. Specifically, Grass pea plants exhibiting vigorous growth and a healthy appearance were intentionally selected to isolate rhizobia from their root nodules. The isolated rhizobia were then characterized based on their morphological features, biochemical properties, and resistance to abiotic traits. Rhizobial isolates from grass peas exhibited Gram-negative, rod-shaped morphology, milky colony color, and variable colony sizes. Additionally, the majority displayed smooth colony surfaces on yeast extract mannitol agar medium. Based on morphological and biochemical characteristics, the isolates could be grouped under the genus Rhizobium. Optimum growth conditions for these isolates were observed at temperatures between 28 and 38 °C, pH levels ranging from 5 to 8, and salt (NaCl) concentrations of 0.5% and 1%. At a concentration of 20 mL L−1, glyphosate inhibited 5.52–47% of the Rhizobium population. The inhibition percentage increased to 17.1–53.38% at a concentration of 40 mL L−1. However, when exposed to a higher concentration (60 mL/L) of glyphosate, 87% of the isolates were inhibited. The number of colonies after glyphosate exposure was significantly dependent on concentration, and there were notable differences between treatments with varying glyphosate concentrations (p < 0.05). Glyphosate negatively impacted the survival of grass pea rhizobia, leading to a reduction in the Rhizobium population (CFU). However, the effect varied between Rhizobium isolated from grass pea root nodules. [ABSTRACT FROM AUTHOR]

New advance in plant–microorganism interactions research revealed the ability of plants to affect the composition of root-associated microbial communities, selecting for the microorganisms required for their growth in different ecosystems under stress conditions. Yeasts can play important roles in promoting plant growth; however, little information is available in this regard. In this study, we evaluated the ability of Rhodotorula mucilaginosa RSRod01 strain isolated from the root nodules of Trifolium sp. collected from a Pb-Zn mine soil to promote plant growth in vitro by producing a siderophore and extracellular enzymes, and exhibiting antifungal activity, as well as its tolerance to heavy metals and salinity. The results showed that the isolate possessed important plant growth-promoting (PGP) traits, including the capacity to grow at 4% salt concentration and resistance to high levels of heavy metals. Resistance to heavy metals decreased in the following row: Pb2+ > Cu2+ > Co2+ > Zn2+ = Ni2+ > Cd2+> Cr6+. [ABSTRACT FROM AUTHOR]

Screening of 1019 strains of rhizobia Rhizobium leguminosarum and Neorhizobium galegae from the "Symbiont" collection of symbiotic rhizospheric microorganisms of the Institute of Biochemistry and Genetics, Ufa Research Center, Russian Academy of Sciences, which have been isolated from root nodules of 20 leguminous species, for the ability to suppress the growth of related strains of rhizobia was carried out. Inhibition of the growth of competing bacteria by rhizobia was shown to be rather common. On average, when grown on rich media, ~10% of rhizobial strains released antibacterial substances into the medium. At the same time, when a live culture of rhizobia was applied to the lawn of bacteria, the percentage of suppression was higher. The percentage of strains synthesizing antibacterial substances correlated also, to some extent, with the level of genetic diversity of the population of legume microsymbionts. A weak signal of impaired protein synthesis was found in the study of the mechanism of action of metabolites of 20 strains of rhizobia R. leguminosarum bv. viciae from root nodules of Lathyruspalustris and Lathyrusvernus. In other cases, the nature of the antibacterial action of bacterial metabolites could not be determined using the DualRep2 system. [ABSTRACT FROM AUTHOR]

The polytypic species of nodule bacteria Rhizobium leguminosarum (includes biovars viciae and trifolii) and Neorhizobium galegae (biovars orientalis and officinalis) differ in the nucleotide polymorphism of housekeeping genes (hkg) and of symbiotically specialized genes (sym) that control the formation of N2-fixing nodules in leguminous plants. In R. leguminosarum, p-distance values for sym genes are higher than for hkg genes in strains from the same and from different biovars. In N. galegae, differences between biovars in sym genes are higher than in hkg genes, while within biovars, polymorphism in sym genes is lower than in hkg genes. Coefficients of biovar differentiation for both groups of genes are higher in N. galegae than in R. leguminosarum, possibly reflecting the spatial isolation of N. galegae biovars. In these species of rhizobia, the phylogenetic congruence of sym and hkg genes is more pronounced in N. galegae than in R. leguminosarum. This difference indicates an active transfer of sym genes in R. leguminosarum populations possibly representing an important factor of the deep diversification for symbiotic traits in this rhizobia species. [ABSTRACT FROM AUTHOR]

The present review highlights both the fundamental questions of calcium localization, compartmentation, and its participation in symbiosome signaling cascades during nodule formation and functioning. Apparently, the main link of such signaling is the calmodulin...calcium- and calmodulin-dependent protein kinases...CYCLOPS...NIN...target genes cascade. The minimum threshold level of calcium as a signaling agent in the presence of intracellular reserves determines the possibility of oligotrophy and ultraoligotrophy in relation to this element. During the functioning of root nodules, the Ca2+-ATPases activity maintains homeostasis of low calcium concentrations in the cytosol of nodule parenchyma cells. Disturbation of this homeostasis can trigger the root nodule senescence. The same reasons determine the increase in the effectiveness of symbiosis with the help of seed priming with sources of calcium. Examples of calcium response polymorphism in components of nitrogen fixing simbiosis important in practical terms are shown. [ABSTRACT FROM AUTHOR]

Non-specific lipid transfer proteins (nsLTPs) are antimicrobial peptides, involved in several plant biological processes including root nodule nitrogen fixation (RNF). Nodulating plants belonging to the RNF clade establish symbiosis with the nitrogen-fixing bacteria rhizobia (legumes symbiosis model) and Frankia (actinorhizal symbiosis model) leading to root nodule formation. nsLTPs are involved in processes active in early step of symbiosis and functional nodule in both models. In legumes, nsLTPs have been shown to regulate symbiont entry, promote root cortex infection, membrane biosynthesis, and improve symbiosis efficiency. More recently, a nsLTP, AgLTP24 has been described in the context of actinorhizal symbiosis between Alnus glutinosa and Frankia alni ACN14a. AgLTP24 is secreted at an early step of symbiosis on the deformed root hairs and targets the symbiont in the nitrogen-fixing vesicles in functional nodules. nsLTPs are involved in RNF, but their functions and evolutionary history are still largely unknown. Numerous putative nsLTPs were found up-regulated in functional nodules compared to non-infected roots in different lineages within the RNF clade. Here, results highlight that nodulating plants that are co-evolving with their nitrogen-fixing symbionts appear to have independently specialized nsLTPs for this interaction, suggesting a possible convergence of function, which opens perspectives to investigate nsLTPs functions in RNF. [ABSTRACT FROM AUTHOR]

Legume-rhizobium signaling during establishment of symbiotic nitrogen fixation restricts rhizobium colonization to specific cells. A limited number of root hair cells allow infection threads to form, and only a fraction of the epidermal infection threads progress to cortical layers to establish functional nodules. Here we use single-cell analysis to define the epidermal and cortical cell populations that respond to and facilitate rhizobium infection. We then identify high-confidence nodulation gene candidates based on their specific expression in these populations, pinpointing genes stably associated with infection across genotypes and time points. We show that one of these, which we name SYMRKL1, encodes a protein with an ectodomain predicted to be nearly identical to that of SYMRK and is required for normal infection thread formation. Our work disentangles cellular processes and transcriptional modules that were previously confounded due to lack of cellular resolution, providing a more detailed understanding of symbiotic interactions. The authors use single-cell analysis to identify genes specifically expressed in plant root cells that respond to infection by nitrogen-fixing rhizobia. They show that one of these genes, SYMRKL1, is required for normal progression of infection. [ABSTRACT FROM AUTHOR]

Purpose: Drought induces mortality in plants; however, how symbioses mediate the plant drought response remains understudied and may be crucial to understanding how shifts in symbioses under climate change scenarios may impact plant drought induced mortality. Methods: Drought was experimentally imposed in parallel on two legume hosts, Acmispon strigosus and Lotus japonicus, whose roots are nodulated by nitrogen fixing rhizobia in different genera. Within each host taxon, greenhouse experiments factorially combined legume genotypes varying in root nodule investment with rhizobia varying in nitrogen fixation capacity, to investigate how costs and benefits of symbiosis modulate plant performance under drought. Results: Net benefits of symbiosis with nitrogen fixing symbionts, namely increased number of leaves and shoot mass, were maintained under drought irrespective of nodulation level or host species, mitigating the carbon strain during drought. Net benefits of symbiosis occurred despite increased water cost associated with the maintenance of nitrogen fixation, costs that were evident even in pre drought baseline conditions. Conclusion: Our results demonstrate that benefits of root nodule symbiosis can be robust to environmental perturbations, and potentially mediate carbon starvation during drought induced mortality events. The investment in symbiosis and its impacts on biomass suggest that in long term droughts legumes may be more limited by carbon than water. Ongoing stability of these associations is predicted, even under extended drought conditions. [ABSTRACT FROM AUTHOR]

Lichens are of great ecological importance but mechanisms regulating lichen symbiosis are not clear. Umbilicaria muhlenbergii is a lichen-forming fungus amenable to molecular manipulations and dimorphic. Here, we established conditions conducive to symbiotic interactions and lichen differentiation and showed the importance of UMP1 MAP kinase in lichen development. In the initial biofilm-like symbiotic complexes, algal cells were interwoven with pseudohyphae covered with extracellular matrix. After longer incubation, fungal-algal complexes further differentiated into primitive lichen thalli with a melanized cortex-like and pseudoparenchyma-like tissues containing photoactive algal cells. Mutants deleted of UMP1 were blocked in pseudohyphal growth and development of biofilm-like complexes and primitive lichens. Invasion of dividing mother cells that contributes to algal layer organization in lichens was not observed in the ump1 mutant. Overall, these results showed regulatory roles of UMP1 in symbiotic interactions and lichen development and suitability of U. muhlenbergii as a model for studying lichen symbiosis. The mechanisms regulating fungal-algal interactions during the formation of lichen symbioses are not clear. Here, Wang et al. establish conditions conducive to symbiotic interactions and lichen differentiation using a fungus amenable to genetic manipulation, showing the importance of a MAP kinase in lichen development. [ABSTRACT FROM AUTHOR]

Nodules are formed as a result of symbiosis with nitrogen-fixing bacteria on the roots of legume plants. Symbiotic nodule development shares common developmental processes with lateral roots, including cell proliferation of the pericycle and cortical cell layers leading to primordium formation, and both these organs are assumed to be evolutionarily related. The progression of their development is realized with the help of phytohormones, in particular auxin and cytokinin. Due to common evolutionary origin, the hormonal pathway and response may have similar functionality in cell fate specification during lateral root and nodule development. It is known that auxin and cytokinin both positively regulate nodule primordia development. However during lateral root development, auxin is a key positive regulator, while cytokinin suppresses lateral root development. Therefore, a comparative review of auxin and cytokinin action in the development of these two organs to elucidate how their identity is established should be of special interest. This review discusses the involvement of auxin and cytokinin in the development of symbiotic nodules and lateral roots, with a special focus on the similarity and differences of their action during lateral root and nodule developmental processes. The spatio-temporal peculiarities of auxin and cytokinin biosynthesis, transport and response during lateral root and symbiotic nodule formation are reviewed, which should help to clarify how the identity of these two root lateral organs depends on auxin-cytokinin interplay. [ABSTRACT FROM AUTHOR]

Due to the ecological importance of mutualism between reef-building corals and symbiotic algae (Family Symbiodiniaceae), various transcriptomic studies on coral-algal symbiosis have been performed; however, molecular mechanisms, especially genes essential to initiate and maintain these symbioses remain unknown. We investigated transcriptomic responses of Acropora tenuis to inoculation with the native algal symbiont, Symbiodinium microadriaticum, during early life stages, and identified possible symbiosis-related genes. Genes involved in immune regulation, protection against oxidative stress, and metabolic interactions between partners are particularly important for symbiosis during Acropora early life stages. In addition, molecular phylogenetic analysis revealed that some possible symbiosis-related genes originated by gene duplication in the Acropora lineage, suggesting that gene duplication may have been the driving force to establish stable mutualism in Acropora, and that symbiotic molecular mechanisms may vary among coral lineages. Investigation of the transcriptomic responses of Acroporatenuis to inoculation with the native algal symbiont identifies genes that may support coral-algal symbiosis during early life stages of corals. [ABSTRACT FROM AUTHOR]

Purpose: Treatment of hyperthyroidism caused by autonomously functioning thyroid nodules (AFTN) with 131I often leads to undesirable hypothyroidism. Radiofrequency ablation (RFA) has emerged as a promising alternative. This retrospective analysis aimed to examine the efficacy of, and postprocedural hypothyroidism after, RFA for AFTN. Methods: Patients with hyperthyroidism caused by AFTN and treated with RFA were included if follow-up of at least 1 year was available. Cure was defined as thyroid medication–free biochemical euthyroidism. To predict cure, patient and treatment factors were analysed. A distinction was made between solitary toxic adenoma (STA) and toxic multinodular goitre (TMG). Results: Forty-eight patients (36 STA, 12 TMG) were included. One year post-RFA cure rate was 72% in STA versus 25% in TMG (p = 0.004). One patient developed hypothyroidism. In 11 patients that remained hyperthyroid, a second RFA was successful in 83% of STA and 40% of TMG patients. At last available follow-up, this amounted to a total cure rate of 81% in STA and 33% in TMG (p = 0.002). In STA, cured patients had a higher baseline TSH and a lower FT3 than non-cured patients (p = 0.026 and 0.031). Cure was observed in 91% of patients when > 2.1 kJ/mL was delivered during RFA, compared to 44% when less energy was administered. Conclusion: The efficacy of RFA was nearly 3 times higher in STA patients compared to TMG. Severity of hyperthyroidism and kJ/mL delivered during RFA predicts cure. Direct comparison to the current standard of care is needed to implement RFA in treatment of hyperthyroidism caused by AFTN. [ABSTRACT FROM AUTHOR]

Global warming and ocean acidification represent major threats to coral reefs, the combination of these stressors may have concomitant impacts on coral holobionts. However, the molecular mechanisms of the impacts and synergistic effects of acidification and warming on coral holobionts are rarely known, particularly from the point of coral-Symbiodiniaceae symbioses. In this study, using branching Acropora valida and massive Galaxea fascicularis as representatives in a laboratory system simulating acidification (pH 7.7) and/or warming (32 °C), the response of coral host, Symbiodiniaceae and their symbiotic association were investigated by high-throughput transcriptome sequencing (RNA-Seq) with pH 8.1 and 26 °C as controls. Based on differentially expressed genes (DEGs) analysis, acidification and/or warming show greater impacts on the gene expression of coral host than its symbiotic Symbiodiniaceae. Synergistic effects of combined acidification and warming are suggested by comparison with single stress, especially the synergistic negative effects on coral-Symbiodiniaceae symbioses are suggested, because the expression of most of the genes related to photosynthesis, nutrient metabolism and transfer, and the symbionts recognition are downregulated indicating the instability of the coral-Symbiodiniaceae symbioses. This study provides molecular evidence for the synergy of acidification and warming on coral holobionts. In particular, the synergistic negative effects on the nutrients and symbionts recognition-based coral-Symbiodiniaceae symbioses are highlighted, which is helpful for predicting the response of coral holobionts to future global climate changes. [ABSTRACT FROM AUTHOR]

Using Col2.3GFP transgenic mice expressing GFP in maturing osteoblasts, we isolated Col2.3GFP+ enriched osteoblasts from 3 sources. We performed RNA-sequencing, identified 593 overlapping genes and confirmed these genes are highly enriched in osteoblast differentiation and bone mineralization annotation categories. The top 3 annotations are all associated with endoplasmic reticulum and Golgi vesicle transport. We selected 22 trafficking genes that have not been well characterized in bone for functional validation in MC3T3-E1 pre-osteoblasts. Transient siRNA knockdown of trafficking genes including Sec24d, Gosr2, Rab2a, Stx5a, Bet1, Preb, Arf4, Ramp1, Cog6 and Pacs1 significantly increased mineralized nodule formation and expression of osteoblast markers. Increased mineralized nodule formation was suppressed by concurrent knockdown of P4ha1 and/or P4ha2, encoding collagen prolyl 4-hydroxylase isoenzymes. MC3T3-E1 pre-osteoblasts with knockdown of Cog6, Gosr2, Pacs1 or Arf4 formed more and larger ectopic mineralized bone nodules in vivo, which was attenuated by concurrent knockdown P4ha2. Permanent knockdown of Cog6 and Pacs1 by CRISPR/Cas9 gene editing in MC3T3-E1 pre-osteoblasts recapitulated increased mineralized nodule formation and osteoblast differentiation. In summary, we have identified several vesicle trafficking genes with roles in osteoblast function. Our findings provide potential targets for regulating bone formation. [ABSTRACT FROM AUTHOR]

Most plants interact with various soil microorganisms as they grow through the soil. Root nodule symbiosis by legumes and rhizobia is a well-known phenomenon of plant–microbe interactions in the soil. Although microscopic observations are useful for understanding the infection processes of rhizobia, nondestructive observation methods have not been established for monitoring interactions between rhizobia and soil-grown roots. In this study, we constructed Bradyrhizobium diazoefficiens strains that constitutively express different fluorescent proteins, which allows identification of tagged rhizobia by the type of fluorophores. In addition, we constructed a plant cultivation device, Rhizosphere Frame (RhizoFrame), which is a soil-filled container made of transparent acrylic plates that allows observation of roots growing along the acrylic plates. Combining fluorescent rhizobia with RhizoFrame, we established a live imaging system, RhizoFrame system, that enabled us to track the nodulation processes with fluorescence stereomicroscope while retaining spatial information about roots, rhizobia, and soil. Mixed inoculation with different fluorescent rhizobia using RhizoFrame enabled the visualization of mixed infection of a single nodule with two strains. In addition, observation of transgenic Lotus japonicus expressing auxin-responsive reporter genes indicated that RhizoFrame system could be used for a real-time and nondestructive reporter assay. Thus, the use of RhizoFrame system is expected to enhance the study of the spatiotemporal dynamics of plant–microbe interactions in the soil. [ABSTRACT FROM AUTHOR]

Legume plants rely upon multipartite interactions between rhizobia and bacterial endophytes within root nodules to facilitate plant growth. This study aimed to isolate and identify indigenous endophytic bacteria from root nodules of Sulla aculeolata L. in Northeast Morocco. Based on their tri-calcium phosphate (TCP) solubilization capacity, five endophytes were chosen for further evaluation of their plant growth traits. All isolates were hydrogen cyanide (HCN) and siderophore producers, while only BCH24 tested positive for ACC deaminase activity. Indole-3-acetic acid (IAA) synthesis ranged from 1.27 mgL− 1 to 2.89 mgL− 1, while soluble phosphate concentrations was between 7.99 mg L− 1 and 110.58 mg L− 1. Additionally, all the endophytes were able to produce more than two lytic enzymes. Based on the analysis of 16 S rRNA gene sequences five isolates were identified as Enterobacter sp (BCH13, BCH2), Pseudomonas sp (BCH16, BCH24), and Serratia sp (BCH10). The strains inhibited the growth of three phytopathogenic fungi, with BCH13 exhibiting the highest rate against Aspergillus ochraceus (45%), followed by BCH24 against Fusarium oxysporum (40%) and Botrytis cinerea (35%), respectively. In vivo inoculation of halotolerant strains Enterobacter hormaechei (BCH13) and Pseudomonas moraviensis (BCH16) under gnotobiotic conditions revealed that co-inoculation with Rhizobium sullae KS6 improved plant development compared to single inoculation, making it a promising eco-friendly bio-inoculant for legume Sulla flexuosa L. production. [ABSTRACT FROM AUTHOR]

Plants develop several external and internal mechanisms to increase their tolerance to heavy metals (HMs) toxicity including cadmium (Cd). Symbiosis with arbuscular mycorrhizae fungi (AMF) is one of the plants' strategies to tolerate HMs toxicity. Nitric oxide (NO), as a signaling molecule, is also involved in physiological responses of plants to various stresses. The present work was conducted as a factorial completely randomized design with three replications to study the effects of Funneliformis mosseae fungi and Sodium nitroprusside (SNP, 100 mM) as a donor of NO alone, in combination (AMF + SNP) on corn plant growth, and internal detoxification mechanisms of Cd toxicity in a Cd-contaminated calcareous soil (0, 25, 50, and 100 mg Cd kg−1). The results showed that under Cd stress, AMF inoculation and/or foliar application of SNP significantly increased plant growth (32% to 103% for shoot and 44% to 84% for root) by decreasing Cd concentration in corn plant tissues (23% to 46% for shoot and 19% to 40% for root). Cd-induced oxidative stress was mitigated by AMF and/or SNP by enhancing the activities of antioxidant enzymes, including superoxide dismutase (SOD) and catalase (CAT), and concentration of non-enzymatic antioxidants such as glutathione (GSH) and phytochelatin (PC). Increasing the tolerance index (TI) and decreasing the transfer factor (TF) in the corn plants treated with AMF and/or SNP, confirm the efficient role of SNP and AMF in stimulating the detoxification mechanisms of Cd within the plant cells, which was more pronounced at the lowest Cd level (25 mg Cd kg−1). In conclusion, symbiotic associations of corn plants with AMF alone or in combination with SNP mitigated the detrimental effect of Cd toxicity in corn grown in Cd-contaminated calcareous soil. The corn's internal detoxification mechanisms lowered the Cd concentration in plant tissue which resulted in the improvement of the corn's growth parameters. [ABSTRACT FROM AUTHOR]

Identifying the ecological forces that structure root-associated microbial communities is an essential step toward more sustainable agriculture. Legumes are widely utilized as model plants to study selective forces and their functioning in plant-microbial interactions owing to their ability to establish mutualism with rhizobia. Root nodules act as symbiotic organs to optimize the cost-benefit balance in this mutualistic relationship by modulating the number of nodules. However, it is not known whether the number of nodules is related to the structure of root-associated bacterial communities. Here, the root-associated bacterial communities of soybean grown in native soil by means of soybean cultivars with super- or normal nodulation were investigated across four developmental stages. We compared ecological processes between communities and found decreased relative importance of neutral processes for super-nodulating soybean, although the overall structures resembled those of normal-nodulating soybean. We identified the generalist core bacterial populations in each root-associated compartment, that are shared across root-associated niches, and persist through developmental stages. Within core bacterial species, the relative abundances of bacterial species in the rhizosphere microbiome were linked to host-plant functional traits and can be used to predict these traits from microbes using machine learning algorithms. These findings broaden the comprehensive understanding of the ecological forces and associations of microbiotas in various root-associated compartments and provide novel insights to integrate beneficial plant microbiomes into agricultural production to enhance plant performance. [ABSTRACT FROM AUTHOR]

The relationships between symbionts and insects are complex, and symbionts usually have diverse ecological and evolutionary effects on their hosts. The phloem sap-sucking aphids are good models to study the interactions between insects and symbiotic microorganisms. Although aphids usually exhibit remarkable life cycle complexity, most previous studies on symbiotic diversity sampled only apterous viviparous adult females or very few morphs. In this study, high-throughput 16S rDNA amplicon sequencing was used to assess the symbiotic bacterial communities of eleven morphs or developmental stages of the social aphid Pseudoregma bambucicola. We found there were significant differences in bacterial composition in response to different morphs and developmental stages, and for the first time, we revealed male aphids hosted very different symbiotic composition featured with low abundance of dominant symbionts but high diversity of total symbionts. The relative abundance of Pectobacterium showed relatively stable across different types of samples, while that of Wolbachia fluctuated greatly, indicating the former may have a consistent function in this species and the latter may provide specific function for certain morphs or developmental stages. Our study presents new evidence of complexity of symbiotic associations and indicates strong linkage between symbiotic bacterial community and host age and morph. [ABSTRACT FROM AUTHOR]

The BYPASS1-related gene (BPS1) encodes a protein with an unknown functional domain that regulates plant organ growth and development by inhibiting the continuous production of a root-derived long-distance signaling molecule called bypass (bps). We conducted a comprehensive study to investigate the BPS gene family in soybean and identified twenty-three BPS genes in Glycine max and twenty BPS genes in Glycine soja (wild soybean). Collinearity analysis revealied the existence of multiple orthologs of soybean BPS genes in wild soybean, indicating incomplete conservation between the BPS genes of soybean and wild soybean. Phylogenetic analysis successfully categorized all BPS genes into five distinct groups. We further scrutinized their chromosomal locations, gene structures, conserved motifs, cis-acting elements, and expression patterns. Leveraging publicly available data on genetic variation, phenotypic variation, and single-cell transcriptome sequencing of root nodules, we discovered a potential association between BPS genes and multiple soybean traits, particularly those related to the root nodule phenotype. This pioneering study provides a systematic and comprehensive examination of the BPS gene family in soybean. The findings establish a robust foundation for future investigations into the functional roles of BPS genes in plant growth and development. [ABSTRACT FROM AUTHOR]

Compared to the well-studied model legumes, where symbiosis is established via root hair entry, the peanut is infected by Bradyrhizobium through the crack entry, which is less common and not fully understood. Crack entry is, however, considered a primitive symbiotic infection pathway, which could be potentially utilized for engineering non-legume species with nitrogen fixation ability. We utilized a fluorescence-labeled Bradyrhizobium strain to help in understanding the crack entry process at the cellular level. A modified plasmid pRJPaph-bjGFP, harboring the codon-optimized GFP gene and tetracycline resistance gene, was created and conjugated into Bradyrhizobium strain Lb8, an isolate from peanut nodules, through tri-parental mating. Microscopic observation and peanut inoculation assays confirmed the successful GFP tagging of Lb8, which is capable of generating root nodules. A marking system for peanut root potential infection sites and an optimized sample preparation protocol for cryostat sectioning was developed. The feasibility of using the GFP-tagged Lb8 for observing crack entry was examined. GFP signal was detected at the nodule primordial stage and the following nodule developmental stages with robust GFP signals observed in infected cells in the mature nodules. Spherical bacteroids in the root tissue were visualized at the nodules' inner cortex under higher magnification, reflecting the trace along the rhizobial infection path. The GFP labeled Lb8 can serve as an essential tool for plant-microbe studies between the cultivated peanut and Bradyrhizobium, which could facilitate further study of the crack entry process during the legume-rhizobia symbiosis. [ABSTRACT FROM AUTHOR]

During legume-rhizobia symbiosis, differentiation of the symbiosome (engulfed intracellular rhizobia) is necessary for successful nitrogen fixation. To control symbiosome differentiation, host cell subcellular components, e.g., ER (endoplasmic reticulum), must adapt robustly to ensure large-scale host protein secretion to the new organelle. However, the key components controlling the adaption of ER in nodule cells remain elusive. We report that Medicago BID1, a nodule-specific signal peptide peptidase (SPP), is central to ER structural dynamics and host protein secretion. In bid1, symbiosome differentiation is blocked. BID1 localizes specifically to the ER membrane and expresses exclusively in nodule cells with symbiosomes. In the wild type ER forms proximal association structures with symbiosomes, but not in bid1. Consequently, in bid1 excessive ER stress responses are induced and ER-to-symbiosome protein secretion is impaired. In summary, a nodule-specific SPP is necessary for ER-symbiosome proximal association, host protein secretion, and symbiosome differentiation. During nitrogen fixing symbiosis, rhizobia enter legume nodule cells to form the symbiosome. Here the authors report that a nodule-specific signal peptide peptidase is essential for the molecular communication between host cells and the symbiont. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) analogs, like BPA, could have adverse effects on human health including bone health. The aim was to determine the effect of BPF, BPS and BPAF on the growth and differentiation of cultured human osteoblasts. Osteoblasts primary culture from bone chips harvested during routine dental work and treated with BPF, BPS, or BPAF for 24 h at doses of 10–5, 10–6, and 10–7 M. Next, cell proliferation was studied, apoptosis induction, and alkaline phosphatase (ALP) activity. In addition, mineralization was evaluated at 7, 14, and 21 days of cell culture in an osteogenic medium supplemented with BP analog at the studied doses. BPS treatment inhibited proliferation in a dose-dependent manner at all three doses by inducing apoptosis; BPF exerted a significant inhibitory effect on cell proliferation at the highest dose alone by an increase of apoptosis; while BPAF had no effect on proliferation or cell viability. Cell differentiation was adversely affected by treatment with BPA analogs in a dose-dependent, observing a reduction in calcium nodule formation at 21 days. According to the results obtained, these BPA analogs could potentially pose a threat to bone health, depending on their concentration in the organism. [ABSTRACT FROM AUTHOR]

Inadvertent accumulation of arsenic (As) in rice (Oryza sativa L.) is a concern for people depending on it for their subsistence, as it verily causes epigenetic alterations across the genome as well as in specific cells. To ensure food safety, certain attempts have been made to nullify this highest health hazard encompassing physiological, chemical and biological methods. Albeit, the use of mycorrhizal association along with nutrient reinforcement strategy has not been explored yet. Mechanisms of response and resistance of two rice genotypes to As with or without phosphorus (P) nutrition and Serendipita indica (S. indica; S.i) colonization were explored by root transcriptome profiling in the present study. Results revealed that the resistant genotype had higher auxin content and root plasticity, which helped in keeping the As accumulation and P starvation response to a minimum under alone As stress. However, sufficient P supply and symbiotic relationship switched the energy resources towards plant's developmental aspects rather than excessive root proliferation. Higher As accumulating genotype (GD-6) displayed upregulation of ethylene signaling/biosynthesis, root stunting and senescence related genes under As toxicity. Antioxidant defense system and cytokinin biosynthesis/signaling of both genotypes were strengthened under As + S.i + P, while the upregulation of potassium (K) and zinc (Zn) transporters depicted underlying cross-talk with iron (Fe) and P. Differential expression of phosphate transporters, peroxidases and GSTs, metal detoxification/transport proteins, as well as phytohormonal metabolism were responsible for As detoxification. Taken together, S. indica symbiosis fortified with adequate P-fertilizer can prove to be effective in minimizing As acquisition and accumulation in rice plants. [ABSTRACT FROM AUTHOR]