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Protein extracts from green leaves, consisting of mainly RuBisCO, have potential applications for human consumption. However, their properties are highly influenced by the extraction process applied. This work assessed the impact of the extraction method on the solubility profile and emulsifying properties of two protein concentrates from perennial ryegrass, obtained using two different approaches. These two methods differed in the application (or absence) of a heating step (50 °C for 30 min) to improve the removal of chloroplast material. The functionality of both protein concentrates was highly influenced by the isoelectric point of the proteins. The extract containing less residual chloroplast material showed greater solubility, up to 40 % more, and superior emulsifying capacity and stability, at non-acidic pH, similar to WPI. At pH above 6, the protein extract which contained residual chloroplast material was significantly less soluble, which limited its performance as emulsifier. Therefore, the extraction process critically impacted the final product's functionality. This work demonstrated that effectively removing chloroplast material is essential to achieve targeted techno-functional properties of an ingredient and the food product in which it is used. [Display omitted] • Protein concentrates from perennial ryegrass were explored as food emulsifiers. • Extraction method impacted the functional properties of the proteins. • Heating step during protein extraction improved emulsification properties. • Interfacial properties of both concentrates were highly influenced by the pH. • Balance between extraction yield and functional properties should be considered. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is a fructan-accumulating plant constituting one of the most important grassland species with high herbage production, nutritive value and digestibility for grazing cattle. Although fructans were reported to be involved in plant defense acting as antioxidants or stress signals, their contribution in root protection is still to be explored. In roots, atypical defense is provided by the "Root Extracellular Trap" or "RET" at the root-soil interface. The molecular composition and structural organization of the RET are essential to provide root defense against pathogen attacks and abiotic stresses. The RET was reported to be mainly composed of polysaccharides (homogalacturonan, xylogalacturonan, xyloglucan) and proteoglycans such as arabinogalactan proteins (AGPs). Our aim is to characterize the RET composition of L. perenne using cell imaging techniques and a wide range of monoclonal antibodies directed against epitopes from cell wall glycomolecules and to investigate the potential presence of fructans. Interestingly, we found that both mucilage and cell wall surface of border cells were enriched in AGP epitopes. An increased amount of the AGP-containing mucilage was produced by L. perenne root tip in response to both elicitor and osmotic stress. Fructan epitopes were also detected in root cap cells and appeared to be released in the RET under stress conditions. Taken together our findings suggest that AGPs together with fructans are involved in root response of L. perenne to environmental stresses. • The root tip of perennial ryegrass produced border cells of different morphologies. • The root extracellular trap (RET) of perennial ryegrass contained abundant mucilage rich in arabinogalactan protein (AGP). • Fructan epitopes are released within the RET in response to PEG-induced osmotic stress and flagellin 22 elicitation. • Fructans, together with AGPs are promising candidates in root response to environmental stress in perennial ryegrass. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) and arsenic (As) are two highly toxic heavy metals and metalloids that coexist in many situations posing severe threats to plants. Our investigation was conducted to explore the different regulatory mechanisms of ryegrass (Lolium perenne L.) responding to individual and combined Cd and As stresses in hydroponics. Results showed that the ryegrass well-growth phenotype was not affected by Cd stress of 10 mg·L-1. However, As of 10 mg·L-1 caused rapid water loss, proline surge, and chlorosis in shoots, suggesting that ryegrass was highly sensitive to As. Transcriptomic analysis revealed that the transcription factor LpIRO2 mediated the upregulation of ZIP1 and YSL6 that played an important role in Cd tolerance. We found that the presence of As caused the overexpression of LpSWT12 , a process potentially regulated by bHLH14, to mitigate hyperosmolarity. Indoleacetic acid (IAA) and abscisic acid (ABA) contents and expression of their signaling-related genes were significantly affected by As stress rather than Cd. We predict a regulatory network to illustrate the interaction between transporters, transcription factors, and signaling transduction, and explain the antagonism of Cd and As toxicity. This present work provides a research basis for plant protection from Cd and As pollution. [Display omitted] • The physiological response of ryegrass suggests its adaptability to Cd, and sensitivity to As. • Cd substitute Fe intake would be mediated by LpIRO2. • Overexpressed LpSWT12 and bHLH14 participates in regulating hyperosmosis induced by As stress. • IAA and ABA signaling is involved in Cd and As stresses resistance. • We establish ryegrass regulatory network in response to combined As and Cd stresses. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is a widely used cool season turfgrass with outstanding turf quality and grazing tolerance. High temperature is the key factor restricting the distribution of perennial ryegrass in temperate and sub-tropic regions. In this study, we found that one HEAT SHCOK TRANSCRIPTION FACOTR (HSF) class A gene from perennial ryegrass, LpHSFA3 , was highly induced by heat stress. LpHSFA3 is localized in nucleus and functions as a transcription factor. Ectopic overexpression of LpHSFA3 in Arabidopsis improved thermotolerance and rescued heat sensitive deficiency of athsfa3 mutant. Overexpression of LpHSFA3 in perennial ryegrass enhanced heat tolerance and increased survival rate in summer season as evidenced by decreased EL and MDA, increased number of green leaves and total chlorophyll content. LpHSFA3 binds to the HSE region in LpHSFA2a promoter to constitutively activate the expression of LpHSFA2a and downstream heat stress responsive genes. Ectopic overexpression of LpHSFA2a consequently rescued thermal sensitivity of athsfa3 mutant and enhanced thermotolerance of athsfa2 mutant. Perennial ryegrass protoplasts with overexpression of LpHSFA3 and LpHSFA2a exhibited induction of similar subsets of heat responsive genes. These results indicated that transcription factor LpHSFA3 functions as positive regulator of LpHSFA2a to improve thermotolerance of perennial ryegrass, providing further evidence to understand the regulatory networks of plant heat stress response. • LpHSFA3 and LpHSFA2a were significantly induced by heat stresss. • LpHSFA3 improves plant heat tolerance and survival rate in summer season. • LpHSFA3 directly activates the expression of LpHSFA2a. • LpHSFA2a enhances plant heat tolerance. [ABSTRACT FROM AUTHOR]

Forestry and fruit industry is a unique and advantageous industry in Xinjiang, China, and it is an important channel for farmers to increase income. With limited land resources and a shortage of forage in southern Xinjiang, farmers began to establish a fruit-grass interplanting model to improve the comprehensive economic benefits of orchards. The objective of this study was to explore the effects of apple/ryegrass intercropping system on root spatial distribution and competition, and to evaluate the performance of field microclimate, soil physical properties and productivity under intercropping. In the study, three different planting patterns were designed: sole-cropped apple (The spacing of the rows of apple trees was 4.0 m, and the plant spacing was 1.0 m), sole-cropped ryegrass (Strip sowing, row spacing was 0.25 m), and apple/ryegrass intercropping (The distance from apple row to ryegrass row was 1.0 m). Two-year field experiments were conducted to measure the root length density (RLD), specific root length (SRL), interspecific competitiveness index, soil moisture content, organic matter content, air temperature, relative humidity, wind speed, yield, land equivalent ratio (LER) and aggressivity. Compared with sole cropping, intercropping reduced the RLD of apple and ryegrass and increased the SRL of ryegrass. The competition space between apple and ryegrass was concentrated in the soil area of 100 cm horizontally and 0–20 cm vertically, and apple was more competitive than ryegrass. Intercropping increased the content of soil moisture and organic matter and improved the microclimate of farmland, decreased the air temperature, increased the relative humidity of an orchard, and decreased wind speed. Although intercropping reduced ryegrass and apple yield, land equivalent ratio (LER) was 1.27–1.30, indicating that intercropping improved land use efficiency. Root competition led to an uneven distribution of root length density (RLD) and specific root length (SRL). The plasticity of root morphology and root spatial distribution was key to adapting to competition and maximizing the absorption of water and nutrients in apple/ryegrass agroforestry systems. Apple/ryegrass intercropping system maximizes resource utilization and reduces interspecies resource competition. It improved land use efficiency, improved the comprehensive benefits of fruit and grass production. [Display omitted] • The root niche separation of apple and ryegrass reduced the competition for resources. • Intercropping apple and ryegrass increased soil water content and organic matter content. • Intercropping increased the relative humidity of an orchard, decrease the air temperature and wind speed. • Although the yield of ryegrass and apple decreased, intercropping increased land use efficiency. [ABSTRACT FROM AUTHOR]

The temporal profile of methane (CH 4) emissions from ruminants is affected by feed composition and forage type. This study aimed to 1) describe and compare the post-feeding pattern of CH 4 emissions from lambs fed fresh ryegrass substituted with graded levels of forage rape, and 2) to evaluate the association between the magnitude of the variation in CH 4 emission patterns and organic fermentation products quantified in pre- and- post- feeding rumen content samples. Methane emissions were measured at approximately 6 min intervals in respiration chambers from 70 lambs (n = 14 per treatment) fed ryegrass only (FR0) or as a proportion, 0.25 forage rape + 0.75 ryegrass (FR25), 0.50 forage rape + 0.50 ryegrass (FR50), 0.75 forage rape + 0.25 ryegrass (FR75), and forage rape only (FR100). The magnitude of the variability in CH 4 emissions was defined as the ratio of maximum to minimum CH 4 emissions in a 24 h period. This ratio was correlated (P < 0.05) with the proportions of major short chain fatty acids, and calculated hydrogen (H 2) available per unit of glucose fermented (H 2 /GEF), quantified in rumen content samples collected pre- and- post- feeding. The CH 4 emission profile after each feeding followed an asymmetrical positively skewed shape for FR0 to FR75, but not in lambs fed FR100. The lowest CH 4 emission rates were observed before morning feeding which was followed by a CH 4 peak within the 2 h after feeding, and then the CH 4 emissions decreased until the next feeding. In FR100 lambs, the CH 4 emission rate was, unexpectedly, relatively constant after feeding, without any clear CH 4 peaks. The magnitude of the variability in the CH 4 emission rate increased when the pH of rumen contents and H 2 /GEF measured in pre-feeding samples decreased. Including forage rape at 0.75, or greater proportion, in the diet of lambs drastically changed the CH 4 emissions pattern, likely due to a continuous low pH in the rumen which is detrimental for methanogenesis. In conclusion, the daily variation in CH 4 emissions decreased with increasing forage rape inclusion in the diet of sheep and this was associated with a decreasing acetate proportion in the rumen liquid. • Lambs fed 100% forage rape had relatively constant CH 4 emissions throughout the day. • Adding increasing pasture to the forage rape increased the variability of CH 4. • H 2 available per unit of glucose fermented was correlated to the variability of CH 4. [ABSTRACT FROM AUTHOR]

Policy measures have been taken to improve water quality in the Netherlands. These measures include the abolishment of derogation, which allowed dairy farmers to go beyond the maximum application of 170 kg nitrogen (N) from organic fertiliser per hectare, and additional measures of the 7th Nitrates Action program. Grass-clover swards, known for their symbiotic N fixation, could be a strategy to deal with stricter N policies and can potentially improve the environmental sustainability and economic viability of Dutch dairy farms. The aim was to assess the effects of stricter N policies on the farm structure, farm income and environmental performance of a representative Dutch dairy farm on a sandy soil, and to assess the effect of incorporating perennial ryegrass-red white clover (GC rw) swards and perennial ryegrass-white clover (GC w) swards into the grassland management of this farm using a model. A whole-dairy farm linear programming model was used with the objective function to maximize farm income. The model was combined with a farm nutrient balance and life-cycle assessment to determine the impact on nutrient surpluses and greenhouse gas emissions. We modelled a representative Dutch dairy farm with perennial ryegrass (PRG) before and after implementing stricter N policies. Thereafter, the implications of implementing GC rw and GC w swards was assessed. Including the policy measures increased the share of maize land (+12%), decreased the number of dairy cows (-9 cows), reduced farm income (€-18,858 yr-1), led to similar greenhouse gas emissions (∼800 kg carbon dioxide equivalents (CO 2 -eq) per tonne (t) of fat and protein corrected milk (FPCM)), and resulted in a lower N surplus (-65 kg ha-1 yr-1) and phosphate surplus (-4.4 kg ha-1 yr-1) for a scenario with only PRG. The use of GC rw and GC w swards could partly compensate for the reduction in farm income (€+9,255 up to +14,706 yr-1). A combination of PRG, GC rw and GC w resulted in the highest farm income. The use of grass-clover swards only had the most positive effect on greenhouse gas emissions (767 kg CO 2 -eq t-1 FPCM) and N surplus (113 kg ha-1 yr-1). Sensitivity analysis showed the importance of yields and feed characteristics on the obtained farm income. Grass-clover swards might partly compensate for the negative economic consequences of stricter N policies for Dutch dairy farms. Furthermore, implementing grass-clover swards reduced the GHG emission intensity of milk, but not always nutrient surpluses per hectare of farm land. [Display omitted] • Grass-clover swards might be a strategy for dairy farmers to deal with stricter nitrogen policies in the Netherlands. • Economic and environmental effects of stricter nitrogen policies were quantified with a whole farm model. • Number of cows, labour income and nutrient surpluses decreased under stricter policies. • Grass-clover swards improved labour income and carbon footprint but not always nutrient surpluses. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify the farm gate nitrogen (N) offset potential of perennial ryegrass (Lolium perenne L.; PRG) white clover (Trifolium repens L.; WC) swards by comparing the herbage and milk production from dairy farmlets that were simulations of full farming systems. A study was established where 120 cows were randomly assigned to 4 farmlets of 10.9 ha (stocking rate: 2.75 cow/ha), composed of 20 paddocks each. Cows were fed 526 kg of DM of concentrate on average each year. The 4 grazing treatments were PRG-only at 150 or 250 kg of N/ha and PRG-WC at 150 or 250 kg of N/ha. Cows remained in their treatment group for an entire grazing season and were re-randomized as they calved across treatments each year. As cows calved in the spring as standard practice in Ireland, they were rotationally grazed from early February both day and night (weather permitting) to mid-November, to a target postgrazing sward height of 4.0 cm. Mean sward WC content was 18.1% and 15.4% for the 150 and 250 kg of N/ha PRG-WC treatments, respectively over the 3-yr period. When WC was included, lowering the N rate did not reduce pregrazing yield, pregrazing height, or herbage removed, but those factors decreased significantly when WC was absent. Total annual herbage DM production was 13,771, 15,242, 14,721, and 15,667 kg of DM/ha for PRG-only swards receiving 150 or 250 kg of N/ha and PRG-WC swards receiving 150 or 250 kg of N/ha, respectively. In addition, when WC was present, compressed postgrazing sward heights were lower (4.10 vs. 4.21 cm) and herbage allowance (approximately 17 kg/cow feed allocation per cow per day) higher than the high-N control (+ 0.7 kg of DM/cow per day). There was a significant increase in milk production, both per cow and per hectare, when WC was included in PRG swards. Over the 3-yr study, cows grazing PRG-WC had greater milk (+304 kg) and milk solids (+31 kg of fat + protein) yields than cows grazing PRG-only swards. This significant increase in milk production suggests that the inclusion of WC in grazing systems can be effectively used to increase milk production per cow and per hectare and help offset nitrogen use. This result shows the potential to increase farm gate N use efficiency and reduce the N surplus compared with PRG-dominant sward grazing systems receiving 250 kg of N/ha, without negatively affecting milk solids yield or herbage production, thus increasing farm profit by €478/ha. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is critical to plants in metal-contaminated soils because it participates in various biochemical reactions during plant growth. However, the mechanisms of P in mitigating the toxicity of heavy metals to ryegrass root is still veiled. In this study, the physiological and biochemical dynamics of the ryegrass root under various cadmium (Cd) and P conditions were investigated in a hydroponic system. Cd stress decreased the length of the ryegrass root, but P application enhanced the root elongation to reduce the Cd concentration in the root. Both Cd and P dosages were positively correlated with hemicellulose 1 content, pectin content, and PME activity, while having a negative effect on cellulose content. Moreover, the addition of 80 mg L−1 P increased the contents of pectin and hemicellulose 1 by 2.5 and 5.8% even with 4 mg L−1 Cd. In addition, P supply increased pectin methylesterbase activity under Cd stress, which further changed the extra-cytoplasmic structures and cell wall composition. Thus, exogenous P promoted the immobilization of Cd onto the cell wall and protected protoplast primarily through indirectly regulating the binding capacity of the root cell wall for Cd. [Display omitted] • P addition significantly increased the length and activity of ryegrass roots. • Cd absorbed by roots was enhanced by P but most Cd was adsorbed by the cell wall. • The polysaccharides content and PME activity were altered by exogenous P. • The dilution and redistribution of Cd induced by P reduced the Cd toxicity in roots. [ABSTRACT FROM AUTHOR]

Sustainable technologies for the recovery of rare earth elements (REE) from waste need to be developed to decrease the volume of ore mining extractions and its negative environmental consequences, while simultaneously restoring previously impacted lands. This is critical due to the extensive application of REE in everyday life from electronic devices to energy and medical technologies, and the dispersed distribution of REE resources in the world. REE recovery by plants has been previously studied but the feasibility of REE phytoextraction from a poorly soluble solid phase (i.e., nanoparticles) by different plant species has been rarely investigated. In this study, the effect of biostimulation and bioaugmentation on phytorecovery of REE nanoparticles (REE-NP) was investigated by exposing ryegrass seeds to REE-NP in hydroponic environments. This was studied in two sets of experiments: bioaugmentation (using CeO 2 nanoparticles and Methylobacterium extorquens AM1 pure culture), and biostimulation (using CeO 2 or Nd 2 O 3 nanoparticles and endogenous microorganisms). Addition of M. extorquens AM1 in bioaugmentation experiment including 500 mg/L CeO 2 nanoparticles could not promote the nanoparticles accumulation in both natural and surface-sterilized treatments. However, it enhanced the translocation of Ce from roots to shoots in sterile samples. Moreover, another REE-utilizing bacterium, Bacillus subtilis , was enriched more than M. extorquens in control samples (no M. extorquens AM1) , and associated with 52% and 14% higher Ce extraction in both natural (165 μg/g dried-plant) and surface-sterilized samples (136 μg/g dried-plant), respectively; showing the superior effect of endogenous microorganisms' enrichment over bioaugmentation in this experiment. In the biostimulation experiments, up to 705 μg/g dried-plant Ce and 19,641 μg/g dried-plant Nd could be extracted when 500 mg/L REE-NP were added. Furthermore, SEM-EDS analysis of the surface and longitudinal cross-sections of roots in Nd 2 O 3 treatments confirmed surface and intracellular accumulation of Nd 2 O 3 -NP. These results demonstrate stimulation of endogenous microbial community can lead to an enhanced REE phytoaccumulation. [Display omitted] • Engineered rare earth elements (REE) nanoparticles phytoextraction was investigated. • Biorecovery of solid phase REE leads to less ore mining and leaching treatments. • Biostimulated ryegrass seeds could recover both Ce and Nd nanoparticles. • REE-utilizing microorganisms were enriched and promoted REE phytoextraction. • Ryegrass can be used as a landscape and resource recovery system, simultaneously. [ABSTRACT FROM AUTHOR]

Once littered, disposable e-cigarettes present a complex type of waste in the environment. They typically contain a lithium battery, electronics to produce vapour and remnant e-liquid, all of which could leach into the environment. The effects of littered e-cigarettes are not well understood, and they have not been tested in terrestrial ecosystems. To address this, an experiment was set up to assess how leachate from e-cigarettes with or without a battery, but also e-liquid on its own can alter fundamental physical characteristics of Lolium perenne (perennial ryegrass) when irrigated with contaminated water. After 31 days, shoot length of L. perenne was not measurably affected, but the biomass was significantly reduced by 30% when e-liquid, and 24% when leachate from intact e-cigarettes was present compared to control plants. Plants grown with leachate or e-liquid displayed a significant level of early senescence of leaf apices, and the chlorophyll content was increased. Furthermore, root biomass was significantly less (29–46%) compared to the control. Leachate from used disposable e-cigarettes can affect the performance of plants when entering the soil ecosystem, therefore stricter regulations are needed to prevent this new type of electronic litter from becoming more widespread. [Display omitted] • E-cigarettes are increasingly littered in the environment where they can be hazardous. • E-liquid and leachate from e-cigarettes caused Lolium perenne to senesce within 31 days. • E-liquid and leachate from e-cigarettes affected above and belowground biomass of L. perenne. [ABSTRACT FROM AUTHOR]

The current study highlights the synthesis of Zn-enriched biosourced catalysts (BIOCATs) obtained from ryegrass (Lolium perenne L.) cultivated on contaminated soils located in the North of France (Noyelles-Godault and Auby, Hauts-de-France). These cultures were located on brownfield land, next to two former industrial sites where the zinc and lead metallurgists Metaleurop and Nyrstar were installed. Physical and morphological properties of BIOCATs were compared to heterogeneous catalysts (CATs) prepared from commercial zinc chloride and montmorillonite K10. The catalysts were thermally activated (120 °C, 280 °C or 500 °C). BIOCATs have been further compared to CATs and different commercial metal chlorides in terms of efficiency in the synthesis of anti-inflammatory agents, Piroxicam and Meloxicam, both of them being involved in the inhibition of cyclooxygenases (COX) and being the main ingredients of the Feldene® and Mobic® drugs, respectively. BIOCAT-assisted synthesis resulted in the best reaction yields (84% and 78%, respectively) among all the tested catalysts. The results indicated that ryegrass provides appropriate quantity of biomass and can be considered as a bio-ore resource to improve green metrics in an environmental context involving clean and green technologies. Furthermore, the Zn/Cd and Zn/Pb ratios obtained in the ashes of ryegrass shoots were in general comprised between 153 and 202. This result demonstrated the excellent selectivity of ryegrass for zinc at the expense of the more problematic Cd and Pb, which are carcinogenic, mutagenic and reprotoxic. Future efforts are now needed to use BIOCATs in the synthesis of other high value-added molecules. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The first-time volatiles of Rathybacter toxicus are identified with cultivating bacteria with a novel approach. • Associated endophytic bacteria were explored for their antibacterial potential against R. toxicus. • Pantoea agglomerans and Pseudomonas cedrina could provide a new avenue for developing bio-control strategies against R. toxicus. The study involved the isolation of bacteria from the surface of Rathayibacter toxicus infested ryegrass seeds, followed by an analysis of volatile organic compounds (VOCs) to identify biomarkers associated with each bacterial species. Among the four isolated bacteria (a species of Pantoea , two species of Pseudomonas and R. toxicus), three were evaluated for their antibiosis potential against R. toxicus. The main objective of this research was to characterize the volatile compounds produced by R. toxicus and to assess the capability of the other three bacteria to serve as biological control agents. The volatile chemicals were identified by using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC–MS) in the aforementioned bacterial species. The identified compounds such as 1-nonanol, geraniol, decanoic acid and 2-decanone may serve as biomarkers for R. toxicus. Additionally, obtained information on VOCs may facilitate chemical communication between bacteria and the nematode which is responsible to carry it to the ryegrass plant. During the antibiosis assay, Pantoea agglomerans and Pseudomonas cedrina , among the endophytic/epiphytic bacterial species, produced compounds that significantly inhibited R. toxicus growth in vitro, with capacity values 22.7 ± 2.3 and 20.0 ± 2.0, respectively. In conclusion, this study's findings have significant implications for the management of annual ryegrass toxicity (ARGT), as they highlight the promising potential of P. agglomerans and Ps. cedrina as viable candidates for biological control strategies in ARGT management. [ABSTRACT FROM AUTHOR]

In this study, municipal waste pyrolytic char (PEWC) was prepared by pyrolysis from municipal solid waste extracted in landfills, and Fe-based modified pyrolytic char (Fe-PEWC) was prepared by modification. Focusing on the evaluation of the stabilization capacity of Fe-PEWC for vanadium (V) and chromium (Cr) in soils, the effects of PEWC addition on soil properties, bioavailability and morphological distribution of V and Cr, ryegrass growth, and V and Cr accumulation were thoroughly investigated. The results of pot experiment showed that the application of PEWC and Fe-PEWC significantly (P < 0.05) improved soil properties (such as pH, EC, total nitrogen, available phosphorus, available potassium, and organic matter). After 42 days of cultivation, Fe-PEWC has a better fixation effect on heavy metals, and the bioavailable V and Cr of 3% Fe-PEWC decreased by 14.96% and 19.48%, respectively. The exchangeable state and reducible state decreased, while the oxidizable state and residual state increased to varying degrees. The Fe-PEWC can effectively reduce the accumulation of V and Cr in ryegrass by 71.25% and 76.43%, respectively, thereby reducing their toxicity to plants. In summary, modified pyrolytic char can effectively solidify heavy metals in soil, improve soil ecology and reduce the toxicity to plants. The use of excavated waste as a raw material for the preparation of soil heavy metal curing agent has the significance of resource recycling, low price, and practical application. [Display omitted] • The pyrolysis char (PEWC and Fe-PEWC) was prepared by excavated municipal solid waste. • The addition of PEWC and Fe-PEWC enhances soil properties. • Fe-PEWC amendments simultaneously reduced V and Cr bioavailability. • Fe-PEWC converts more acid extractable fraction accessible V/Cr into less accessible forms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic biochar and ryegrass can remediate heavy metal co-contaminated soils. • Magnetic biochar and ryegrass maintain the stability of soil organic carbon pool. • Magnetic biochar spheres can adsorb more Cr and Ni. • Biochar sustains ryegrass to fix heavy metals continuously. Biochar is a very promising material for soil remediation. However, most studies mainly focus on the adsorption ability of biochar on one heavy metal, which is difficult to evaluate the actual remediation effect since soils were contaminated with multiple heavy metals. In order to improve the soil remediation efficiency, we used the joint remediation method of magnetically modified biochar and ryegrass to remediate the soil polluted by compound heavy metals (chromium, nickel, copper, zinc, arsenic and cadmium), and evaluate the effect on the process of organic carbon mineralization in polluted soils. It was found that magnetic biochar and ryegrass together decreased the concentrations of Cr, Ni, Cu, Zn, As, and Cd in soils by 24.12 %, 23.30 %, 22.01 %, 9.98 %, 14.83 %, and 15.08 %, respectively, and reduced the available fractions. Ryegrass roots were the main accumulation part of heavy metals, and the order of enrichment effect was ranked as Zn > As > Cr > Cu > Ni > Cd. In addition, magnetic biochar can maintained the stability of the organic carbon pool, and inhibited the emission of volatile organic compounds from ryegrass. Overall, this study indicates that magnetic biochar spheres combined with ryegrass is an effective method for heavy metals co-contaminated soils, and has the excellent remediation ability for actual co-contaminated soils. [ABSTRACT FROM AUTHOR]

While plant toxicity reduction remains the primary metric for judging the success of metal immobilization in soil, the suitability of microorganisms as universal indicators of its effectiveness in various contaminated soils remains a point of contention. This study assessed the sensitivity of microbial bioindicators in monitoring metal immobilization success in smelter-impacted soils. It compared plants and microorganisms as indicators of the efficiency of natural Fe–Mn nodules from the Gulf of Finland in immobilizing metals in soils contaminated by a Ni/Cu smelter, on the Kola Peninsula, Murmansk region, Russia. Perennial ryegrass (Lolium perenne) was grown on nodule-amended and control soils. Plant responses in the smelter-impacted soils proved to be sensitive and robust indicators of successful metal immobilization. However, microbial responses exhibited a more complex story. Despite the observed reductions in soluble metal concentrations, shoot metal contents in ryegrass, and significant improvements in plant growth, certain microbial bioindicators were unresponsive to metal immobilization success brought about by the addition of Fe–Mn nodules. Among microbial bioindicators studied, community-level physiological profiling, microbial biomass carbon, and basal respiration were sensitive indicators of metal immobilization success, whereas the number of saprotrophic, oligotrophic, and Fe-oxidizing bacteria and fungi, the biomass of bacteria and fungi, and enzymatic activity were less robust indicators. Interestingly, the correlations between different microbial responses measured were weak or even negative. Some microbial responses also exhibited negative correlations with plant biomass. These findings underscore the need for further research on comparative evaluations of plants and microorganisms as reliable indicators of metal immobilization efficacy in polluted environments. [Display omitted] • Plant biomass was a sensitive and robust indicator of metal immobilization success. • Among 15 microbial indicators, 7 were sensitive to metal immobilization. • In 85% of cases, microbial response correlations were not statistically significant. [ABSTRACT FROM AUTHOR]

Australia has tropical, summer dominant rainfall in the north transitioning to temperate, winter dominant rainfall in the south. Temperate pasture species with a cool season growth pattern are commonly grown in the south, but tropical pasture species that are highly productive and responsive to summer rainfall, may also have a role in southern pasture systems with climate change. Determine the value of replacing temperate pastures with tropical pastures; and assess the emergence success of tropical grasses in response to historic climate change in eastern Australia. The AusFarm model was used to test replacing lucerne (Medicago sativa L.) (L); annual ryegrass (Lolium rigidum L.)/subterranean clover (Trifolium subterraneum L.) (RC); or lucerne/annual ryegrass/subterranean clover (LRC) with tropical pasture at varying rates of inclusion at five locations across the subtropical-temperate transition zone. The emergence success of tropical grasses with a bare fallow, short fallow and increased ground cover management was also tested. The modelling covered two periods, the Far Climate (1960–1990) and the Near Climate (1990–2020). Tropical pastures had higher plant growth in late summer-early autumn when temperate pastures are less active. Pasture growth decreased from the Far to the Near Climate period across all sites. The pastures with L lost the most production over this period, with minimal change in other pasture types. Supplementary feeding was reduced at all sites with the inclusion of tropical pastures. The cost of supplementary feeding from the Far to the Near Climate increased by $20/ha with increased variability between years, which in-turn decreased gross margin by an average of $26/ha. Tropical pastures improved profitability on average by $24/ha (11%), but with different responses between environments. At the low rainfall sites (Condobolin and Leeton) there was a substantial benefit when tropical grass-clover (TC) pasture replaced L, but at the higher rainfall sites (Cowra and Wagga Wagga) the benefit was replacing RC with TC. There was a gradient of successful emergence from very high (>90%) in the north, to reduced opportunities in the south (<45%), and marginal influence of sowing management. Adding tropical pastures to grazing systems with temperate pastures increased summer-autumn growth, the animal requirements met by pasture, and gross margins. Profitability of livestock systems decreased with climate change, but this can be overcome by optimising pasture composition. Fewer years are favourable for establishment of tropical pastures in more temperate environments, therefore establishment strategies need to be adjusted and field tested. • Tropical pastures have potential in temperate grazing systems due to climate change. • Tropical pastures increased plant growth over summer when temperate pastures are less active. • Tropical pastures decreased supplementary feeding and increased gross margin. • Poor establishment conditions limit the use of tropical grasses in temperate environments. • Profit of livestock systems decreased with climate change but less so with tropical pastures. [ABSTRACT FROM AUTHOR]

Complex rhizoremediation is the main mechanism of phytoremediation in organic-contaminated soil. Low molecular weight organic acids (LMWOAs) in root exudates have been shown to increase the bioavailability of contaminants and are essential for promoting the dissipation of contaminants. The effects of root exudates on the dissipation of organophosphate esters (OPEs) in soil are unclear. Consequently, we studied the combined effects of root exudates, soil enzymes and microorganisms on OPEs (tri (1-chloro-2-propyl) phosphate (TCPP) and triphenyl phosphate (TPP)) dissipation through pot experiments. Oxalic acid (OA) was confirmed to be the main component of LMWOAs in root exudates of ryegrass. The existence of OA increased the dissipation rate of OPEs by 6.04%–25.50%. Catalase and dehydrogenase activities were firstly activated and then inhibited in soil. While, urease activity was activated and alkaline phosphatase activity was inhibited during the exposure period. More bacteria enrichment (e.g., Sphingomonas , Pseudomonas , Flavisolibacter , Pontibacter , Methylophilus and Massilia) improved the biodegradation of OPEs. In addition, the transformation paths of OPEs hydrolysis and methylation under the action of root exudates were observed. This study provided theoretical insights into reducing the pollution risk of OPEs in the soil. [Display omitted] • Oxalic acid was the main component of ryegrass root exudates. • OPEs stress enhanced the secretion of oxalic acid. • The root exudates of ryegrass promoted the degradation of OPEs in soil. • Microbial communities were significantly affected by root exudates. [ABSTRACT FROM AUTHOR]

In this study, a straw-based degradable mulch film was prepared with a similar heat and moisture retention effect to polyethylene mulch film and good magnetically controlled-release performance for glyphosate to promote growth of crop and inhibit grass simultaneously. [Display omitted] • A straw-based mulch film with magnetically controlled-release glyphosate (SMFG@ASO) is prepared. • Magnetic field can control the release of glyphosate from SMFG@ASO effectually. • The degradable SMFG@ASO can reduce plastic pollution and waste of straw resource. • SMFG@ASO can promote corn growth and inhibit ryegrass germination significantly. To solve three main problems in agriculture (plastic mulch pollution, difficult straw recycling, and low utilization efficiency of pesticides), a multifunctional mulch film (MF) was fabricated. In this study, corn straw was mixed with xanthan gum, glyphosate (Gly), Fe 3 O 4 , and MIL-100(Fe) to obtain a MF named as SMFG with magnetically controlled-release Gly. To improve the hydrophobicity and stability of SMFG, the surface was coated by amino silicone oil (ASO) to get SMFG@ASO. SMFG@ASO had well insulation and moisture retention properties close to polyethylene MF. Meanwhile, the weight loss ratio of SMFG@ASO increased with time and could reach 59% underground in 120 d, indicating the good biodegradation behavior of SMFG@ASO. Importantly, pot experiment showed that SMFG@ASO could significantly promote growth of crop and inhibit grass. Besides, earthworm experiment illustrated that SMFG@ASO possessed a high biosafety and could increase the relative abundance of beneficial bacteria (Flavobacterium) from 0.08 to 0.21 and soil quality. Thus, this study provides a new method to prepare a straw-based degradable MF for resolving the problems of plastic pollution and waste of straw resources simultaneously to realize the integration of herbicide and MF. [ABSTRACT FROM AUTHOR]

In sheep production systems, diet type is an important factor affecting the eating quality of the meat produced. The objective of this study was to assess the effect of binary swards on the slaughter performance, descriptive sensory profile, consumer liking and instrumental texture of lamb meat. Five dietary treatments were investigated, perennial ryegrass (Lolium perenne L.; PRG), PRG plus white clover (Trifolium repens L.; PRG+WC), PRG plus red clover (Trifolium pratense L.; PRG+RC), PRG plus chicory (Chicorium intybus L.; PRG+Chic) and PRG plus plantain (Plantago lanceolata L.; PRG+Plan). Post – weaning sixty Texel sired crossbred lambs (n = 12 per dietary treatment) were selected from the main cohort of lambs born in 2022 and further balanced for sex and reared litter size. The M. longissimus thoracis et lumborum (LTL) was obtained from each lamb post-slaughter. Meat samples were analysed by a trained sensory panel, a consumer panel as well as Warner-Bratzler shear force (WBSF) measurements. All data were analysed using a linear mixed model PROC MIXED in SAS. Mean slaughter weights of 46.0 ± 0.36 kg and cold carcass weights of 22.2 ± 0.51 kg were achieved with no differences observed across dietary treatments (P > 0.05). On average, lambs were 217 d of age at slaughter. Lambs finished on PRG and PRG+Plan had similar growth rates, however binary mixtures containing PRG plus any one of WC, RC (P < 0.01) or Chic (P < 0.05) increased average daily gain (ADG) and reduced the number of days required for lambs to reach slaughter (P < 0.05), relative to lambs grazing the PRG monoculture. Meat from PRG+Plan lambs was scored lower by the trained sensory panel for initial tenderness (P < 0.001) and overall tenderness (P < 0.001) when compared to meat from any other dietary treatment. Consumers scored meat from PRG or PRG+WC lambs higher for tenderness (P < 0.05) and flavour (P < 0.01) in comparison to meat produced from PRG+Plan lambs. Relative to meat from PRG+Plan lambs, PRG, PRG+WC and PRG+Chic lamb meat scored higher for overall liking (P < 0.01) when assessed by the consumer panel. Results show that companion forage inclusion increased lamb growth performance in the post-weaning period thus reducing age at slaughter. However, findings suggest that the addition of plantain to the grazed sward may negatively affect the eating quality of lamb meat, highlighting the need to consider diet type in tandem with meat eating quality when selecting finishing systems for pasture fed lambs. • Companion forage inclusion generally increased average daily gain post-weaning and reduced age at slaughter. • Meat from lambs grazing perennial ryegrass and plantain received lower scores for sensory tenderness when assessed by the trained and consumer panels. • Meat quality attributes must be considered when selecting lamb-finishing diets. [ABSTRACT FROM AUTHOR]

Multipurpose cropping is promoted to provide biomass to meet the growing demand for biorefining, but excessive biomass removal may decrease soil C stocks and ecosystem multifunctionality. Here, soil C stocks across 0–200 cm depth and soil ecosystem multifunctionality at 0–40 cm were evaluated based on a 19–year field experiment, including three multipurpose cropping systems as continuous cotton (CC), ryegrass–sweet sorghum double cropping (RS) and perennial switchgrass (SG). Compared to CC, RS and SG increased the soil C stocks by 19% and 28%, and N stocks by 19% and 23% at 0–200 cm, respectively. The soil C stocks were positively correlated with belowground C input and negatively associated with C mineralization. RS and SG increased soil ecosystem multifunctionality by 16.8 and 15.7 folds at 0–20 cm and 0.34 and 0.61 folds at 20–40 cm relative to CC, respectively. The benefit of soil C stocks and ecosystem multifunctionality was more pronounced in SG than in RS due to the deeper root system. In conclusion, relative to continuous monoculture, rotational and perennial cropping can enhance soil C sequestration, maintain soil function, and provide feedstock for bioenergy. [Display omitted] • Rotational and perennial cropping increased soil carbon (C) stocks at 0–2 m depth. • Rotational and perennial cropping boost soil ecosystem multifunctionality (SEMF). • Higher C stocks under perennials are due to higher C input and lower mineralization. • Perennial overperforms rotational cropping in enhancing soil C stocks and SEMF. [ABSTRACT FROM AUTHOR]

Green manure application is a feasible agricultural practice to effectively improve soil fertility. However, our understanding of the effects and mechanisms of different green manure residue amounts on soil fertility improvement remains insufficient. Regarding a new type of Italian ryegrass (Lolium multiflorum L.)-rice (Oryza sativa L.) rotation (IRR) system in Southern China, the effects of six Italian ryegrass residue amounts (IRR0: 15,700 kg·ha−1, IRR1: 30,700 kg·ha−1, IRR2: 35,400 kg·ha−1, IRR3: 40,100 kg·ha−1, IRR4: 44,800 kg·ha−1, IRR5: 49,500 kg·ha−1) on the soil nutrient contents, soil enzyme activities, and bacterial communities were evaluated. Compared to the CK, appropriate amounts of Italian ryegrass residue application increased total nitrogen (36.45–37.38 %), soil organic carbon (15.34–26.55 %), microbial biomass carbon (14.07–33.93 %) and microbial biomass nitrogen (30.20–47.65 %) (P < 0.05). The activities of soil polyphenol oxidase, urease, β-glucosidase, peroxidase, cellulase, and total enzyme were also improved significantly in comparison with the CK (P < 0.05). Bacterial community structures in response to IRR were different from those in the CK. The application of Italian ryegrass residue significantly enhanced the relative abundance of beneficial taxa, including Acinetobacter , Pseudomonas , and Arenimonas (P < 0.05). The 30,700–35,400 kg·ha−1 Italian ryegrass residue exhibited the most practical amounts for enhancing soil fertility, soil enzyme activities, and altering soil microbial communities, suggesting that the improvement effects of green manure application on soil were dependent on the residue returning amounts. These findings suggest that the returning of Italian ryegrass residue is an effective land management measure to realize efficient and sustainable utilization of paddy fields. • Italian ryegrass residue improved the soil properties and bacteria communities in an amount-dependent manner. • The dominant bacteria communities were constructed according to their nutrient utilization capacity. • Relative abundances of the dominant bacteria were associated with soil biochemical properties. • Application of 30,700-35,400 kg·ha-1 Italian ryegrass residue was recommended. [ABSTRACT FROM AUTHOR]

Crop nitrogen (N) fertilization diagnoses via the N nutrition index (NNI)-yield relationship have been tested for several crop species, but a cross-species comparison of that relationship has not been performed yet. This study aimed to perform a cross-species comparison of the relationship between NNI and yield with emphasis on the yield sensitivity to N deficiency, slope of the models. Additionally, we conducted an evaluation to determine the best NNI sampling moment to predict relative yield, with focus on major grain crops. Based on a recently published global dataset to parametrize critical dilution curves , we calculated integrated NNI, instantaneous NNI, relative yield, and relative shoot biomass for annual ryegrass, tall fescue, maize, potato, rice, and wheat. We obtained 238 observations to fit integrated NNI-relative yield linear mixed-effects models and 1606 observations to fit instantaneous NNI-relative yield models. Subsequently, we performed a sensitivity analysis to determine the best NNI sampling moment to predict relative yield, with focus on major grain crops (maize, rice, and wheat). Our results show that there was low inter-species variation of sensitivity to N deficiency, i.e., the slope of the relationship between relative yield and integrated NNI. For grain crops, instantaneous NNI around anthesis demonstrated a better predictive capability for relative yield, outperforming other vegetative stages. This finding contributed to improving the understanding of the association between relative yield and NNI with implications for breeding programs, nutrient management practices, and crop modelling. Most importantly, this study is a contribution to improving the N nutrition diagnosis for several crop species, by using an integral, comparative approach. • The relationship between relative yield and integrated NNI was similar across species. • The slope of relative yield-integrated NNI shown limited variation across species. • The relative yield-integrated NNI slopes of maize and potato were the highest. • For grain crops, NNI around anthesis was the strongest predictor of relative yield. [ABSTRACT FROM AUTHOR]

There is an increasing demand for developing new sources of proteins, and plants are considered the preferred alternative to animal proteins. In particular, green leaves are a source of RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase). This work assessed perennial ryegrass as a source of soluble proteins using mild treatments to preserve their functional properties. Two different extraction methods were compared, differing in the presence or abscence of a heating step (at 50 °C for 30 min) aimed to improve the removal of chloroplast material. The method that included the heating step resulted in a protein concentrate with high solubility (>90% at pH 7), and higher concentration of phenolic compounds. On the other hand, avoiding the heating step resulted in a higher extraction yield, but the residual chloroplast material affected the solubility of the final powder (>60% at pH 7). The protein extracts obtained by both methods consisted mainly of RuBisCO and presented a balanced amino acid profile covering the FAO (2011) recommendations for all the essential amino acids. Therefore, perennial ryegrass showed potential to become an alternative source of proteins for food applications with good nutritional value, whose phenolic compound, chlorophyll content and solubility was strongly dependent on the extraction process. [Display omitted] • Perennial ryegrass is an alternative source of proteins for food applications. • The final extracts obtained by both methods were composed mainly by RuBisCO. • Protein extracts had a complete amino acid profile with promising nutritional value. • Heating step during protein extraction improved the removal of chloroplast material. • Balance between extraction yield and protein solubility should be carefully assessed. [ABSTRACT FROM AUTHOR]

The indiscriminate use of sulfadiazine has caused severe harm to the environment, and biodegradation is a viable method for the removal of sulfadiazine. However, there are few studies that consider sulfadiazine biodegradation mechanisms. To comprehensively investigate the process of sulfadiazine biodegradation by plants in a soil system, a potted system that included ryegrass and soil was constructed in this study. The removal of sulfadiazine from the system was found to be greater than 95% by determining the sulfadiazine residue. During the sulfadiazine removal process, a significant decrease in ryegrass growth and a significant increase in antioxidant enzyme activity were observed, which indicates the toxic response and detoxification mechanism of sulfadiazine on ryegrass. The ryegrass transcriptome and soil bacterial communities were further investigated. These results revealed that most of the differentially expressed genes (DEGs) were enriched in the CYP450 enzyme family and phenylpropanoid biosynthesis pathway after sulfadiazine exposure. The expression of these genes was significantly upregulated. Sulfadiazine significantly increased the abundance of Vicinamibacteraceae , RB41 , Ramlibacter, and Microvirga in the soil. These key genes and bacteria play an important role in sulfadiazine biodegradation. Through network analysis of the relationship between the DEGs and soil bacteria, it was found that many soil bacteria promote the expression of plant metabolic genes. This mutual promotion enhanced the sulfadiazine biodegradation in the soil system. This study demonstrated that this pot system could substantially remove sulfadiazine and elucidated the biodegradation mechanism through changes in plants and soil bacteria. [Display omitted] • Sulfadiazine caused severe phytotoxicity and induced oxidative stress in ryegrass. • Ryegrass has mobilized metabolic genes involved in sulfadiazine biodegradation. • Key bacteria in soil are essential for sulfadiazine biodegradation. • This study combined plant and soil processes for biodegradation of sulfadiazine. [ABSTRACT FROM AUTHOR]

Knowledge of the environmental compatibility of pervious concrete with recycled coarse aggregate (RA) is significant, especially when used in riparian buffer areas. In this study, investigations on the growth performance of two grass combinations (I: Festuca and Ryegrass; II: Cosmos bipinnata, Festuca and Ryegrass) and water purification capacity of the pervious concrete with the RA were carried out to evaluate the environmental compatibility; the former was performed by measuring the maximum height and germination rate during 28 days of growth; the latter was measured using a water immersion test with measurements of the nutrient content (NO 3 --N, NO 2 --N, NH 4 +-N, T-N, PO 4 3--P, and T-P) and organic matter (COD and DOC) at certain intervals. Prior to that, the effects of RA grading (5–15 mm, 15–20 mm, 20–25 mm) and water-cement ratio (W/C) (0.4, 0.45, 0.5) on strength and porosity were determined, along with suitable concrete being selected for the test of environmental compatibility. The results showed that a maximum RA grading of 20–15 mm was the best for plant growth, manifesting the greatest maximum height of 9.8 cm and germination rate of 42.42%. Pervious concrete with vegetation can efficiently purify the surrounding water, with a removal efficiency of more than 98% for NH 4 +-N, T-P, PO 4 3--P, and COD. The removal efficiency increased over time, except for the DOC. W/C had no distinct effect on plant growth and matter removal, except for NO 2 --N and NO 3 --N, which increased as W/C increased. This paper highlights the environmental technical merits of pervious concrete with RA and provides technical support for using the material in riparian buffers. • Pervious concrete with RA is an eco-friendly material in riparian zones. • Pervious concrete with vegetation exhibits great water purification performance. • The pervious concrete with a large RA grading is more suitable for plant growth. • Suitable W/C for plant growth is dependent on the grass species. [ABSTRACT FROM AUTHOR]

The primary aim of this study was to assess the impact of liquid (S-LAB) and lyophilized (L-LAB) probiotics sourced from Rye-Grass Lactic Acid Bacteria on broilers experiencing heat stress. The study involved 240 broiler chicks divided into six groups. These groups included a negative control (Control) with broilers raised at a normal temperature (24 °C) on a basal diet, and positive control groups (S-LAB and L-LAB) with broilers under normal temperature receiving a lactic acid bacteria supplement (0.5 mL/L) from rye-grass in their drinking water. The heat stress group (HS) comprised broilers exposed to cyclic heat stress (5–7 h per day at 34–36 °C) on a basal diet, while the heat stress and probiotic groups (S-LAB/HS and L-LAB/HS) consisted of broilers under heat stress supplemented with the rye-grass-derived lactic acid bacteria. Results indicated that heat stress without supplementation (HS) led to reduced body weight gain, T3 levels, citrulline, and growth hormone levels, along with an increased feed conversion ratio, serum corticosterone, HSP70, ALT, AST, and leptin levels. Heat stress also negatively impacted cecal microbiota, decreasing lactic acid bacteria (LABC) while increasing E. coli and coliform bacteria (CBC) counts. Probiotic supplements (S-LAB/HS and L-LAB/HS) mitigated these effects by enhancing broilers' resilience to heat stress. In conclusion, rye grass-derived S-LAB and L-LAB probiotics can effectively support broiler chickens under heat stress, promoting growth, liver function, hormonal balance, gut health, and cecal microbiome ecology. These benefits are likely mediated through improved gut health. [Display omitted] • Heat stress (HS) reduces: BW, T3,CIT, and GH, increases: FCR, Cort, HSP70, ALT, AST, and leptin. • Heat stress alters cecal microbiota: decreases lactic acid bacteria, increases E. coli and coliforms. • Rye grass probiotics (S-LAB and L-LAB) effectively support broiler chickens under HS, promoting growth and gut health. [ABSTRACT FROM AUTHOR]

The dominant ammonium bacteria established in different crop rotations are directly related to the conversion and utilization of nitrogen (N) in paddy soil. This study investigated the ammonia oxidation process in the rice rhizosphere of Italian ryegrass (Lolium multiflorum L.)-rice (IRR), celery (Apium graveolens)-rice (CLR) and winter fallow-rice (WFR) rotations in South China through the amoA functional gene analysis based on Miseq high-throughput sequencing platform and qPCR methods. The abundance of amoA gene in IRR was increased by 116.67 % (P < 0.05) and 42.76 % (P > 0.05) compared with CLR and WFR, respectively. Nitrosomonas became the dominant genus in the rhizosphere of IRR, with the highest relative abundance (59.30 %). The contents of soil organic matter, total N and nitrate nitrogen (NO 3 −-N) in the rice rhizosphere soil in IRR were significantly higher than other two treatments (P < 0.05) by 12.47–14.31 %, 16.88–25.00 %, and 97.48–159.60 %, respectively. Although lower microbial diversity was observed in IRR, the soil fluorescein diacetate hydrolysis enzyme activities and ammonia monooxygenase activities in the rice rhizosphere were higher in IRR than those in CLR and WFR (P < 0.05). Also, the soluble sugar and crude protein of milled rice were highest in IRR among the three rotation treatments (P < 0.05). The ammonia oxidation efficiency of ammonium-oxidizing bacteria was largely dependent on key taxa, such as Nitrosomonas (dominant genus in IRR), rather than the dynamics of AOB community structure. The key amoA- nitrifier taxa of the AOB community developed in IRR are capable of promoting rice production by improving soil N cycle efficiency and reducing the loss of N. Our findings illustrate the regulatory mechanism of IRR on the rice rhizosphere AOB community and reveal the important role of winter ryegrass in promoting soil nitrogen cycling during nutrient transformation of agricultural ecosystems in paddy fields. • Italian ryegrass-rice rotation (IRR) improved N contents and related enzyme activities of rice rhizosphere. • Nitrosomonas was the dominant AOB group in the rice rhizosphere after winter planting of ryegrass. • The ammonia oxidation efficiency of AOB community function mainly depended on Nitrosomonas. • IRR improved soluble sugar and crude protein of rice grains through higher soil nitrogen level. [ABSTRACT FROM AUTHOR]

The type-B response regulator (ARR) family members represent the elements of two-component regulatory systems and play crucial roles in the cytokinin signaling, plant growth, and stress responses. The objective of this study was to characterize type-B ARR genes from perennial ryegrass, and to investigate their roles in regulating to salt tolerance. Twelve type-B ARRs , namely LpARR1 - 12 , were identified in perennial ryegrass. They were clustered into three subgroups and were unevenly distributed on chromosomes. The stress responsive elements (SREs) and hormone responsive elements (HREs) were identified in LpARRs promoters and the transcription of LpARRs genes were responsive to various abiotic stress (heat, salt, and osmotic) and hormonal (cytokinin, ABA, and ethylene) treatments. LpARR10 was strong induced by salt stress, therefore it was selected for function analysis. Overexpressing LpARR10 in Arabidopsis led to a significant improvement in salt tolerance. The LpARR10 -overexpressing (LpARR10 -OE) lines exhibited lower levels of Na+ content compared to WT plants, and the expression levels of SOS1 and SOS3 were significantly higher in the LpARR10 -OE lines. Results of yeast auto-transactivation and plant cell transcriptional activity assays shows LpARR10 is a nucleus localized transcriptional activator and directly bind and transactivated the promoter of SOS1 and SOS3. Together, LpARR10 enhances salt tolerance may via trans-activating SOS1 / SOS3 in Arabidopsis. Knowledge gained in this study will facilitate further functional analysis of LpARRs for molecular breeding of ryegrass and other related grass species. • Overexpressing LpARR10 resulted in a reduction in Na+ content compared to WT plants. • The LpARR10 -OE lines exhibited significantly higher expression levels of SOS1 and SOS3. • LpARR10 acts as a transcriptional activator and positively regulates salt tolerance by up-regulating the expressions of SOS1 and SOS3. [ABSTRACT FROM AUTHOR]