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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]

Cytochrome P450s (CYPs) play crucial roles in regulating plant growth, development, and stress tolerance. In this study, a perennial ryegrass (Lolium perenne) CYP gene, LpCYP72A15, was identified as a candidate gene regulating plant osmotic stress tolerance based on a cDNA library screening in the background of yeast ∆hog1 mutant. LpCYP72A15 is localized in the plastids, and its expression was regulated by osmotic stress and ABA treatment. Overexpressing LpCYP72A15 significantly enhanced plant drought tolerance in both Arabidopsis and perennial ryegrass. Under drought stress, the transgenic ryegrass showed significant lower reactive oxygen species (ROS) levels, higher ROS‐scavenging enzymatic activities, and higher soluble sugar contents than the wildtype plants. Transient over‐expressing the gene also enhanced survival rates of ryegrass mesophyll protoplasts under H2O2‐induced oxidative or mannitol‐enforced osmotic stresses. Taken together, LpCYP72A15 confers oxidative‐ and osmotic‐stress tolerances that positively regulates plant drought tolerance in perennial ryegrass. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is an outstanding turfgrass and forage cultivated in temperate regions worldwide. However, poor tolerance to extreme cold, heat, or drought limits wide extension and cultivation. DEHYDRATION‐RESPONSIVE ELEMENT BINDING FACTOR1s (DREB1s) play a vital role in enhancing plant tolerance to abiotic stress, specifically for low‐temperature stress. In this study, a total of 24 LpDREB1 family members were identified from the released genome of perennial ryegrass. Phylogenetic analysis showed that the LpDREB1 genes are divided into 7 groups that have close relationships with rice homologues. Conserved motif analysis revealed that members within the same group have similar conserved motif compositions. All LpDREB1s lack introns, and the promoter sequences of LpDREB1 genes contain multiple cis‐acting elements associated with stress response, phytohormone signal transduction and plant growth and development. The majority of LpDREB1 genes were upregulated by drought, submergence, heat and cold stress treatments, including LpDREB1H2. Further investigation showed that LpDREB1H2 is localized in the nucleus. Overexpression of LpDREB1H2 in Arabidopsis induced the expression of cold‐responsive (COR) genes, increased the levels of osmotic adjusting substances, and enhanced antioxidant enzyme activities, thus improving the cold tolerance of Arabidopsis. This study lays a foundation for further understanding the function of LpDREB1 genes in perennial ryegrass and provides insights for plant stress tolerance breeding. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is one of the most widely used species for sports fields in temperate climates because of its high wear tolerance. However, wear tolerance of cultivars may vary according to local environmental conditions and turfgrass management. In this study, we evaluated the wear tolerance of six perennial ryegrass cultivars (Adagio, Apple SGL, Equate, Firebird, Principal 2, Tetradark) under two fertility treatments (100 or 200 kg N-ha21-yr21) over 2 years. The field trial was performed at the Experimental Agricultural Farm at the University of Padova in northeastern Italy in a silty loam soil. Plots were arranged in a randomized complete block with three replications and subjected to three traffic events per week using a sports field wear simulator. Turfgrass quality (TQ), percent green cover (PGC), and normalized difference vegetation index (NDVI) were recorded every 2 weeks and averaged over each month. Although perennial ryegrass cultivars responded differently to wear stress, the higher nitrogen (N) rate positively affected the TQ of them all. 'Tetradrak' and 'Equate' had the lowest TQ, especially during the active growing seasons (spring and autumn). However, 'Tetradark' was particularly negatively affected during the cool fall months. The impact of a higher N fertilization rate on PGC and NDVI appeared to be more pronounced in spring than in fall. Furthermore, slight differences among cultivars and treatments were observed in summer and winter when temperatures were a limiting growth factor. [ABSTRACT FROM AUTHOR]

Background: Commercial cultivars of perennial ryegrass infected with selected Epichloë fungal endophytes are highly desirable in certain pastures as the resulting mutualistic association has the capacity to confer agronomic benefits (such as invertebrate pest deterrence) largely due to fungal produced secondary metabolites (e.g., alkaloids). In this study, we investigated T2 segregating populations derived from two independent transformation events expressing diacylglycerol acyltransferase (DGAT) and cysteine oleosin (CO) genes designed to increase foliar lipid and biomass accumulation. These populations were either infected with Epichloë festucae var. lolii strain AR1 or Epichloë sp. LpTG-3 strain AR37 to examine relationships between the introduced trait and the endophytic association. Here we report on experiments designed to investigate if expression of the DGAT + CO trait in foliar tissues of perennial ryegrass could negatively impact the grass-endophyte association and vice versa. Both endophyte and plant characters were measured under controlled environment and field conditions. Results: Expected relative increases in total fatty acids of 17–58% accrued as a result of DGAT + CO expression with no significant difference between the endophyte-infected and non-infected progeny. Hyphal growth in association with DGAT + CO expression appeared normal when compared to control plants in a growth chamber. There was no significant difference in mycelial biomass for both strains AR1 and AR37, however, Epichloë-derived alkaloid concentrations were significantly lower on some occasions in the DGAT + CO plants compared to the corresponding null-segregant progenies, although these remained within the reported range for bioactivity. Conclusions: These results suggest that the mutualistic association formed between perennial ryegrass and selected Epichloë strains does not influence expression of the host DGAT + CO technology, but that endophyte performance may be reduced under some circumstances. Further investigation will now be required to determine the preferred genetic backgrounds for introgression of the DGAT + CO trait in combination with selected endophyte strains, as grass host genetics is a major determinant to the success of the grass-endophyte association in this species. [ABSTRACT FROM AUTHOR]

Background: Drought resistance is a complex characteristic closely related to the severity and duration of stress. Perennial ryegrass (Lolium perenne L.) has no distinct drought tolerance but often encounters drought stress seasonally. Although the response of perennial ryegrass to either extreme or moderate drought stress has been investigated, a comprehensive understanding of perennial ryegrass response to both conditions of drought stress is currently lacking. Results: In this study, we investigated the genetic variation in drought resistance in 18 perennial ryegrass varieties under both extreme and moderate drought conditions. The performance of these varieties exhibited obvious diversity, and the survival of perennial ryegrass under severe stress was not equal to good growth under moderate drought stress. 'Sopin', with superior performance under both stress conditions, was the best-performing variety. Transcriptome, physiological, and molecular analyses revealed that 'Sopin' adapted to drought stress through multiple sophisticated mechanisms. Under stress conditions, starch and sugar metabolic enzymes were highly expressed, while CslA was expressed at low levels in 'Sopin', promoting starch degradation and soluble sugar accumulation. The expression and activity of superoxide dismutase were significantly higher in 'Sopin', while the activity of peroxidase was lower, allowing for 'Sopin' to maintain a better balance between maintaining ROS signal transduction and alleviating oxidative damage. Furthermore, drought stress-related transcriptional and posttranscriptional regulatory mechanisms, including the upregulation of transcription factors, kinases, and E3 ubiquitin ligases, facilitate abscisic acid and stress signal transduction. Conclusion: Our study provides insights into the resistance of perennial ryegrass to both extreme and moderate droughts and the underlying mechanisms by which perennial ryegrass adapts to drought conditions. [ABSTRACT FROM AUTHOR]

Background: Genomic selection has the potential to accelerate genetic gain in perennial ryegrass breeding, provided complex traits such as forage yield can be predicted with sufficient accuracy. Methods: In this study, we compared modelling approaches and feature selection strategies to evaluate the accuracy of genomic prediction models for seasonal forage yield production. Results: Overall, model selection had limited impact on predictive ability when using the full data set. For a baseline genomic best linear unbiased prediction model, the highest mean predictive accuracy was obtained for spring grazing (0.78), summer grazing (0.62) and second cut silage (0.56). In terms of feature selection strategies, using uncorrelated single‐nucleotide polymorphisms (SNPs) had no impact on predictive ability, allowing for a potential decrease of the data set dimensions. With a genome‐wide association study, we found a significant SNP marker for spring grazing, located in the genic region annotated as coding for an enzyme responsible for fucosylation of xyloglucans—major components of the plant cell wall. We also presented an approach to increase interpretability of genomic prediction models with the use of Gene Ontology enrichment analysis. Conclusions: Approaches for feature selection will be relevant in development of low‐cost genotyping platforms in support of routine and cost‐effective implementation of genomic selection. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is a commonly grown pasture species in temperate agriculture, mainly serving as a primary energy source for dairy cows. However, its limited persistence often leads to missed production potential and early resowing, especially in countries that experience summer drought, e.g., Australia and New Zealand. Therefore, understanding the factors influencing perennial ryegrass pasture persistence is crucial for sustainable land management and climate resilience in pasture-based animal production systems. Significant gaps in knowledge exist regarding the factors influencing pasture persistence, as the number of conducted studies in this area remains limited. This study aimed to investigate the factors influencing the expression of persistence in perennial ryegrass populations using airborne and ground-based sensors. A field experiment was conducted in the southwest region of Victoria, Australia, involving ten commercial perennial ryegrass cultivar–endophyte combinations in two different populations. Persistence was evaluated using sensor-based and conventional pasture measurements over two consecutive autumns. The results revealed significant fixed effects of cultivar, endophyte, and environment and their interactions on persistence traits of perennial ryegrass. Cultivars Alto, Samson, and One50 exhibited high levels of persistence when infected with novel endophyte strains. Furthermore, prolonged environmental stresses were found to drive directional selection within pasture populations. The findings emphasise the importance of selecting appropriate cultivar–endophyte combinations and early detection of signs of poor persistence to optimise sward longevity and financial returns from pasture-based animal production systems. This study fills a knowledge gap regarding the factors influencing pasture persistence and provides valuable insights for sustainable pasture management strategies. [ABSTRACT FROM AUTHOR]

Perennial ryegrass is an important turf and forage grass in temperate regions worldwide. Limited genetic gains have been made with current breeding strategies compared with other grass crops, such as rice and maize, which benefit from Filial 1 (F1) hybrid breeding. One of the largest constraints on hybrid breeding in ryegrass is self‐incompatibility preventing inbreeding, as homozygous parental lines are required to develop hybrids with maximal hybrid vigour. Obligate outcrossing in ryegrass has resulted in cultivars with high levels of heterozygosity, lacking trait uniformity across the population. A naturally occurring self‐fertile (SF) locus that overcomes the self‐incompatibility system has been identified in a European perennial ryegrass population. This study crossed the SF locus into an elite cultivar, producing a self‐compatible population that was inbred for several generations. Genotyping‐by‐sequencing (GBS) was used to assess the population structure and degree of inbreeding in the self‐compatible population. Phenotypic analysis indicated that increased homozygosity did not necessarily affect growth and performance. This study concludes that self‐compatible ryegrass is a promising tool for hybrid breeding and agronomic improvement of perennial ryegrass. [ABSTRACT FROM AUTHOR]

This study was designed to understand how drought stress impact on the physiological and molecular status of genetically diverse Lolium perenne L. (perennial ryegrass) populations. The sensitivities of the 36 perennial ryegrass populations were checked against PEG-6000-simulated drought stress by analysing physiological status. Afterward, drought-related gene expressions were evaluated under normal and stressed conditions. The drought stress significantly up-regulated the drought-related genes in P6, P10, P15 and P30, while no difference was observed in drought-sensitive ones. The results collectively showed that four populations (P6, P10, P15, P30) are tolerant to drought stress and activate drought-related genes. Genetic similarities of the populations were also monitored using microsatellite (SSR) markers. The ten SSR primers detected 38 alleles. Surprisingly, the drought-tolerant populations were classified into different groups by principal component (PCA) and cluster analysis, showing that they are genetically different. Moreover, four unique alleles were identified by two SSR primers (P-07, and P-08) in P6, P10 and P15. In addition, the drought-tolerant populations (P6, P10, P15, P30) can be used to develop new perennial ryegrass cultivars for areas having drought problems. [ABSTRACT FROM AUTHOR]

Heat stress can hinder the growth of perennial ryegrass (Lolium perenne L.). Methyl jasmonate (MeJA) applied exogenously can increase heat stress tolerance in plants; however, the regulatory mechanisms involved in heat tolerance mediated by MeJA are poorly understood in perennial ryegrass. Here, the microRNA (miRNA) expression profiles of perennial ryegrass were assessed to elucidate the regulatory pathways associated with heat tolerance induced by MeJA. Plants were subjected to four treatments, namely, control (CK), MeJA pre-treatment (T), heat stress treatment (H), and MeJA pre-treatment + heat stress (TH). According to the results, 102 miRNAs were up-regulated in all treatments, with 20, 27, and 33 miRNAs being up-regulated in the T, H, and TH treatment groups, respectively. The co-expression network analysis between the deferentially expressed miRNAs and their corresponding target genes showed that 20 miRNAs modulated 51 potential target genes. Notably, the miRNAs that targeted genes related to with regards to heat tolerance were driven by MeJA, and they were involved in four pathways: novel-m0258-5p mediated signal transduction, novel-m0350-5p mediated protein homeostasis, miR397-z, miR5658-z, and novel-m0008-5p involved in cell wall component, and miR1144-z and miR5185-z dominated chlorophyll degradation. Overall, the findings of this research paved the way for more research into the heat tolerance mechanism in perennial ryegrass and provided a theoretical foundation for developing cultivars with enhanced heat tolerance. [ABSTRACT FROM AUTHOR]

The main objective of this research was to evaluate the quality of green mass, hay and silage prepared from perennial ryegrass Lolium perenne and tall fescue Festuca arundinacea, grown in monoculture in the experimental plot of the "Alexandru Ciubotaru" National Botanical Garden (Institute), Chisinau, Republic of Moldova. It was established that the concentration of nutrients and energy in whole-plant dry matter of studied grass species, harvested in pre-flowering stage was 10.74-14.10% CP, 3.10-3.58 % EE, 29.95-31.66% CF, 36.35-45.76% NFE, 6.20-19.24 % sugar, 1.54-2.99 % starch, 10.45-14.31% ash, 2.9 g/kg Ca, 2.5-2.7 g/kg P, 8.93-9.49 MJ/kg ME and 4.97-5.06 MJ/kg NEl. The biochemical composition of the prepared silages was: pH= 4.06-4.21, 27.9-28.9 g/kg lactic acid, 0-0.4 g/kg butyric acid, 1.5-5.0 g/kg acetic acid, 9.12-9.67% CP, 3.37-3.99% EE, 39.16-41.30% CF, 30.53-37.37% NFE, 0.33-1.40 % sugar, 0.50-0.60 % starch, 10.98-14.51% ash, 36.34-56.33 mg/kg carotene, 8.31-9.53MJ/kg ME and 4.48-5.34 MJ/kg NEl. The nutritive value of prepared hay: 9.95-10.84% CP, 1.87-2.55 % EE, 36.90-37.32% CF, 38.48-39.99% NFE, 10.82-11.28% ash, 2.5-3.5 g/kg Ca, 2.6-2.7 g/kg P, 8.31-8.85MJ/kg ME and 4.54-493 MJ/kg NEl. The studied grass species contain a lot of nutrients, which make them suitable to be used as multi-purpose feed for livestock. [ABSTRACT FROM AUTHOR]

Three perennial ryegrass (Lolium perenne) populations (R1, R2, and R3) with suspected resistance (R) to acetolactate synthase (ALS) or acetyl-CoA carboxylase (ACCase) herbicides were collected from wheat (Triticum aestivum) fields in northwestern Greece to study the underlying mechanisms of resistance and their impact on growth rate and competitive ability against wheat. Preemergence and postemergence plant dose–response assays showed that the R1 population was cross-resistant to the ALS inhibitors chlorsulfuron, mesosulfuron + iodosulfuron, and pyroxsulam, but susceptible (S) to imazamox. However, all populations were susceptible to the ACCase inhibitors clodinafop-propargyl, clethodim, diclofop-methyl, and pinoxaden. The analysis of the ALS gene sequence revealed a substitution of Pro197 by His or Leu in the ALS enzyme in L. perenne, which is reported for the first time in this weed and indicates a potential mechanism of target site-mediated resistance. The R1 population grown in the absence or presence of wheat competition displayed similar aboveground biomass and tiller number trends, and therefore similar estimated growth rates. In addition, the aboveground biomass of wheat was similarly reduced by both the R1 and S populations, supporting the evidence of their similar competitive ability against wheat. In general, these findings indicate that there is no clear evidence for the fitness advantage of R1 over the S population. [ABSTRACT FROM AUTHOR]

Perennial ryegrass is a grass species used to establish lawns in urban areas where pollution is a major environmental problems. Cadmium (Cd) and nickel (Ni) contribute significantly to these pollutants and may cause photosynthetic limitation. The main objective of this work was to perform a comprehensive analysis of photosynthetic efficiency of perennial ryegrass seedlings under Cd and Ni stress. Some of the main indices of photosynthetic efficiency (prompt and delayed chlorophyll-a fluorescence signals and modulated reflectance at 820 nm) were compared with growth parameters. Two cultivars were tested: 'Niga' and 'Nira'. A decrease in photosystem (PS) II and PSI activity was observed. This was due to an increase in nonradiative dissipation of the PSII antenna, a decrease in PSII antenna size, or a decrease in the number of photosynthetic complexes with fully closed PSII RCs. Efficiency of electron transport was decreased. The effect on the modulated reflectance signal could indicate a restriction in electron flow from PSII to PSI. The correlation between photosynthetic efficiency parameters, such as Area, Fo, Fm, and Fv, and growth parameters, confirmed that some photosynthetic efficiency parameters can be used as indicators for early detection of heavy metal effects. [ABSTRACT FROM AUTHOR]

The detection of beneficial microbes living within perennial ryegrass seed causing no apparent defects is challenging, even with the most sensitive and conventional methods, such as DNA genotyping. Using a near-infrared hyperspectral imaging system (NIR-HSI), we were able to discriminate not only the presence of the commercial NEA12 fungal endophyte strain but perennial ryegrass cultivars of diverse seed age and batch. A total of 288 wavebands were extracted for individual seeds from hyperspectral images. The optimal pre-processing methods investigated yielded the best partial least squares discriminant analysis (PLS-DA) classification model to discriminate NEA12 and without endophyte (WE) perennial ryegrass seed with a classification accuracy of 89%. Effective wavelength (EW) selection based on GA-PLS-DA resulted in the selection of 75 wavebands yielding 88.3% discrimination accuracy using PLS-DA. For cultivar identification, the artificial neural network discriminant analysis (ANN-DA) was the best-performing classification model, resulting in >90% classification accuracy for Trojan, Alto, Rohan, Governor and Bronsyn. EW selection using GA-PLS-DA resulted in 87 wavebands, and the PLS-DA model performed the best, with no extensive compromise in performance, resulting in >89.1% accuracy. The study demonstrates the use of NIR-HSI reflectance data to discriminate, for the first time, an associated beneficial fungal endophyte and five cultivars of perennial ryegrass seed, irrespective of seed age and batch. Furthermore, the negligible effects on the classification errors using EW selection improve the capability and deployment of optimized methods for real-time analysis, such as the use of low-cost multispectral sensors for single seed analysis and automated seed sorting devices. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is a cool‐season turf and forage grass. Heat shock transcription factors (HSFs) play an important role in regulating plant abiotic stress. However, HSFs in perennial ryegrass have rarely been characterized. Here, 25 LpHSFs were identified from the perennial ryegrass genome. Phylogenetic analysis showed that the LpHSFs could be classified into 12 subclasses. Gene structure analysis showed that 22 LpHSFs have only one intron. Cis‐acting elements analysis revealed that the promoter of 15 LpHSFs contained hormone‐responsive and abiotic stress‐responsive elements. Expression profile analysis indicated that 24 LpHSFs were differentially expressed under submerge, drought, heat, and cold stresses. In addition, a subclass C2 gene, LpHSFC2b, was significantly induced by abiotic stresses. The LpHSFC2b protein is localized to the nucleus, and heterologous expression of LpHSFC2b in Arabidopsis improves plant thermotolerance. This study provides insights useful for the breeding of stress tolerance in perennial ryegrass. [ABSTRACT FROM AUTHOR]

In summer 2018, brown stripe symptoms were observed on leaf blades of perennial ryegrass (Lolium perenne L.) used as a turfgrass in an athletic field in Saitama Prefecture, Japan. Bacterial ooze exuded from lesions, from which a pathogenic bacterium was isolated. Inoculation of blades of perennial ryegrass with the isolates reproduced the same symptoms. Pathogenicity and bacteriological properties of the isolates were almost identical to those of Acidovorax avenae, and the identification was supported by phylogenetic analysis. This is the first report of the brown stripe on perennial ryegrass caused by A. avenae (= A. avenae subsp. avenae) in Japan. [ABSTRACT FROM AUTHOR]

α-Ketoglutarate (AKG) is a key intermediate metabolite in the tricarboxylic acid cycle of respiration and a precursor for glutamate, playing important roles in regulating plant growth and stress tolerance. The objectives of this study were to examine effects of AKG on heat tolerance characterized by leaf senescence in a cool-season grass species by foliar application and to determine major metabolites and associated metabolic pathways regulated by AKG for its effects on heat tolerance. Perennial ryegrass (Lolium perenne L.) plants were exposed to heat stress (35/30 °C, day/night) or optimal temperature (25/20 °C, day/night, non-stress control) in controlled-environment growth chambers. The solution containing AKG (5 mM) was applied to leaves by spraying 7 d prior to the initiation of heat stress and every 7 d during the heat stress period. Exogenous application of AKG enhanced heat tolerance in perennial ryegrass, as manifested by significant increases in leaf chlorophyll content, photochemical efficiency, and membrane stability, as well as activities of antioxidant enzymes for H 2 O 2 scavenging in AKG-treated plants relative to untreated control plants exposed to heat stress. Metabolic profiling and pathway analysis demonstrated that exogenous AKG application enhanced metabolite accumulation in four major metabolic pathways, including antioxidant metabolism, amino acid metabolism, glycolysis and tricarboxylic acid cycle of respiration, and pyrimidine metabolism, contributing to AKG-improved heat tolerance in perennial ryegrass. • α-Ketoglutarate (AKG) enhanced heat tolerance in perennial ryegrass. • AKG suppressed heat-induced leaf senescence. • AKG regulated the metabolism of antioxidant, amino acids, pyrimidine, glycolysis, and TCA cycle of respiration. [ABSTRACT FROM AUTHOR]

Incorporating plantain with perennial ryegrass and white clover (RGWC) can improve the quality and quantity of grazing pastures; however, the sowing rate could affect the persistence of plantain, pasture yield, and nutritive value in different seasons. The objective of this study was to evaluate the effect of increasing sowing rates of plantain when established with RGWC on the dry matter (DM) yield, botanical composition, nutritive value, and bioactive compounds of the pasture over the first two years after sowing; and to determine the relationship between plantain content and nutritive characteristics in different seasons. The pasture treatments were RGWC, RGWC + low plantain rate (PLL), RGWC + medium plantain rate (PLM), and RGWC + high plantain rate (PLH). The results showed that annual DM yield was similar between treatments. The average plantain content (including leaves and reproductive stem) was 32, 44, and 48% in PLL, PLM, and PLH, respectively. The plantain composition increased in the first 15 months, then declined rapidly to about 20–30% at day 705 after sowing. Compared with RGWC, the plantain-RGWC pastures (PLL, PLM, PLH) had a higher content of organic matter digestibility (OMD), ash, starch, non-structural carbohydrates (NSC), P, S, Ca, Mg, Na, Cl, Zn, B, Co, aucubin, acteoside, and catalpol, while they contained a lower composition of DM%, acid detergent fibre (ADF), neutral detergent fibre (NDF), crude fat (CF), Fe, and Mn. These differences were linearly associated with the content of plantain leaves in the pasture and were higher in summer and autumn than in spring. In conclusion, incorporating plantain into the RGWC pasture can improve herbage nutritive quality, thus potentially increasing farm productivity and environmental benefits. However, further work is required to investigate management interventions to sustain plantain content beyond two years from sowing. [ABSTRACT FROM AUTHOR]

Under favourable conditions, perennial ryegrass (Lolium perenne) engineered to accumulated high lipid (HL) carbon sink in their leaves was previously shown to also enhance photosynthesis and growth. The greater aboveground biomass was found to be diminished in a dense canopy compared to spaced pots. Besides, the underlying genetic regulatory network linking between leaf lipid sinks and these physiological changes remains unknown. In this study, we demonstrated that the growth advantage was not displayed in HL Lolium grown in spaced pots under low lights. Under standard lights, analysis of differentiating transcripts in HL Lolium reveals that the plants had elevated transcripts involved in lipid metabolism, light capturing, photosynthesis, and sugar signalling while reduced expression of genes participating in sugar biosynthesis and transportation. The plants also had altered several transcripts involved in mitochondrial oxidative respiration and redox potential. Many of the above upregulated or downregulated transcript levels were found to be complemented by growing the plants under low light. Overall, this study emphasizes the importance of carbon and energy homeostatic regulatory mechanisms to overall productivity of the HL Lolium through photosynthesis, most of which are significantly impacted by low irradiances. [ABSTRACT FROM AUTHOR]

Heat stress is a major abiotic stress for temperate plant species with characteristic symptoms of premature leaf senescence. The objectives of this study were to evaluate the physiological effects of cytokinins (CK) and an ethylene inhibitor, aminoethoxyvinylglycine (AVG) on heat‐induced leaf senescence in the temperate perennial grass species, perennial ryegrass (Lolium perenne), and to investigate whether WRKY transcription factors (TFs) could be associated with CK‐ or ethylene‐mediated regulation of heat‐induced leaf senescence by exogenously applying CK or AVG to perennial ryegrass. Perennial ryegrass plants foliar‐sprayed with 6‐benzylaminopurine (6‐BA), and AVG exhibited prolonged stay‐green phenotypes and a lesser degree of leaf senescence under heat stress (35/30°C), as shown by a decline in electrolyte leakage, malondialdehyde content, hydrogen peroxide, and superoxide content, and increased chlorophyll (Chl) content along with reduced activities of Chl‐degrading enzymes (pheophytinase and chlorophyllase) and increased activity of Chl‐synthesizing enzyme (porphobilinogen deaminase) due to 6‐BA or AVG application. The suppression of heat‐induced leaf senescence by 6‐BA or AVG treatment corresponded with the upregulation of LpWRKY69 and LpWRKY70. The LpWRKY69 and LpWRKY70 promoters were predicted to share conserved cis‐elements potentially recognized by TFs in the CK or ethylene pathways. These results indicate that LpWRKY69 and LpWRKY70 may negatively regulate heat‐induced leaf senescence through CK or ethylene pathways, conferring heat tolerance in perennial ryegrass. [ABSTRACT FROM AUTHOR]

The productivity of perennial ryegrass (Lolium perenne L.) is constrained by summer water deficit. We hypothesised that selection for desirable water relations traits might partially mitigate this constraint. Genotypes of a 1970s, and two recent ryegrass cultivars were grown in 55 cm tall pots for three months and exposed to moisture deficit for four weeks, then 66 plants were assessed for shoot (SDW) and root (RDW) dry weight, leaf elongation rate (LER), specific water use (SWU), leaf osmotic potential (OP), OP change, leaf relative water content (RWC), and gravimetric soil moisture. Among the 66 genotypes, SWU ranged from 935 ± 19 to 1754 ± 74 g H2O g–1 DM. In principal component (PC) analysis, PC1 indicated greater growth and lower SWU from greater soil water extraction as the common trait association among genotypes tested and ANOVA of PC scores indicated that recent cultivars outperformed the 1970s cultivar. PC2 indicated water saving by decreased LER and SDW, with increased RDW indicative of summer dormancy. PC3 associated more negative OP with improved SWU and RWC. This experiment demonstrates not only genotypic diversity for SWU but also diversity in trait associations determining SWU, which should be considered when investigating SWU, both in ecology and agronomy research. [ABSTRACT FROM AUTHOR]

Combining several cultivars within species in seed mixtures is often advocated as a means for improving crop or pasture performance. Herbage accumulation (HA) of perennial ryegrass-white clover pastures sown with a single cultivar representing different functional types of perennial ryegrass was compared with the HA of cultivar mixtures over three years in two contrasting environments (Waikato, dryland; Canterbury, irrigated) under dairy cattle grazing. Functional types were: mid-season flowering diploid, late-season diploid, and late-season tetraploid. Mixture treatments (n = 4 at each site) included all binary combinations plus the three-way combination. Mixture HA and the mean HA of the constituent cultivars did not differ for any of the mixture combinations in either environment, apart from winter in Waikato where the mid-diploid plus tetraploid mix out-yielded the mean of the individual cultivars and tended to increase total annual HA. The total annual HA of the mixtures was between 1.0 and 2.3 t DM/ha/year less than the HA of the highest-yielding individual cultivar included in the mixture in six of the eight mixture-environment combinations. While some benefits of mixtures for controlling grazing outcomes were observed, sowing individual high-performing cultivars is a better overall strategy than mixing cultivars to cover a spectrum of traits. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) infected by Epichloë endophytes contains alkaloids that are responsible for toxicosis in many countries. Drought may greatly affect the alkaloids contents of symbionts. The E+ perennial ryegrass was grown in pots with different soil moisture conditions (15%, 30%, 45% and 60% relative saturation moisture content, RSMC) for four months in a greenhouse of Lanzhou University, and then, the aboveground tissues were collected. The levels of peramine and lolitrem B in all plant samples were determined. The results showed that the drought stress significantly (p < 0.05) increased the peramine concentrations of perennial ryegrass but did not affect the lolitrem B concentrations. In addition, the drought stress significantly (p < 0.05) reduced the plant height and dry matter of perennial ryegrass. In conclusion, drought stress affects the peramine concentration in the perennial ryegrass–endophyte symbiont but may not affect the lolitrem B concentration. [ABSTRACT FROM AUTHOR]

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]

Epichloë endophytes in grass associations express a myriad of secondary metabolites which can affect the health of grazing animals and reduce the impact of insect pests on pasture. The ideal endophyte-grass association must have a favourable chemical profile such that the impact on animal health is minimised while the beneficial, deterrent effect on insect pests is maximised. A number of endophyte-perennial ryegrass associations have been successfully commercialised but research is on-going to further improve production in farming systems. Secondary metabolites expressed by endophyte-infected tall fescue include lolines, an animal-safe class of compound which imparts a potent effect on insects. Since endophyte-infected perennial ryegrass does not express lolines, a tall fescue endophyte, AR501, was inoculated into perennial ryegrass in an attempt to improve the insect resistance of this pasture type. In addition to animal safety, it is imperative that consideration is given to the safety of humans consuming animal products derived from livestock grazing the novel pasture. Although pure loline alkaloids have previously been tested on mice it is essential that the entire AR501 endophyte-infected perennial ryegrass matrix is tested since this will result in the exposure of both known and unknown secondary metabolites to mice. Three treatment groups each containing 6 male and 6 female mice were fed diets containing AR501 endophyte-infected perennial ryegrass seed (30%), perennial ryegrass seed containing no endophyte (30%) or a diet without seed (control) for 3 weeks. Mice fed control diet ate more than either of the treatment groups fed a diet containing seed. Male mice fed diet containing Nil endophyte seed ate more than those eating AR501 endophyte-infected perennial ryegrass seed although there was no difference observed in the food intake of female mice. While a few statistically significant differences were observed in the haematology and serum biochemical data, in every instance the difference was restricted to only one gender so is considered unlikely to be of toxicological significance. Mice fed AR501 endophyte-infected perennial ryegrass seed remained healthy throughout the experimental period despite consuming 62,000 mg/kg lolines and 4600 mg/kg peramine per day as well as the wide array of other unknown secondary metabolites expressed by this endophyte. Although animal products may contain additional metabolites as a result of animal metabolism, this experiment raises no food safety concerns for AR501 endophyte-infected perennial ryegrass. [Display omitted] • Endophytes are used to confer beneficial insect pest protection to their host plants. • Endophytes produce a myriad of known and unknown secondary metabolites. • Secondary metabolites consumed by animals could go up the food chain to be consumed by humans. • AR501 endophyte-infected ryegrass seed was fed to mice for 21 days. • The lack of toxicity observed raises no food safety concerns for these compounds. [ABSTRACT FROM AUTHOR]

Information regarding the germination and seedling growth behavior of a potential weed species is an important tool to manage weeds without the use of agricultural chemicals that cause harmful effects on human health and the environment. A series of experiments were directed to investigate the influence of different environmental factors (temperature, pH, NaCl, moisture stress, and seed burial depth) on germination and seedling emergence of perennial ryegrass (Lolium perenne L.) under controlled conditions. Results suggested that 25 °C is the optimum temperature for maximum germination (95%) and seedling growth of perennial ryegrass, however, a quick decline was observed at 35 °C. Seed germination was unaffected by pH levels ranging from 5 to 10. The 92% seed germination was recorded where no salt stress was applied and germination was reduced by 87% at 250 mMNaCl concentration. Seed germination was unaffected by osmotic potential ranges from 0 to − 0.4 MPa thereafter declined and completely inhibited at − 0.8 or − 1.0 MPa. No seed emerged at the soil surface or a soil depth of 6 or 7 cm and 90% emergence occurred at 1 cmsoil depth. The germination and seedlings parameters like time to initial germination, mean germination time, time taken to 50% germination and germination index, root and shoot length, and fresh and dry weight of root and shoot are significantly affected with the environmental factors. The information obtained in this study will be helpful to develop better management strategies for germination and the emergence of perennial ryegrass in areas where it has the ability to rapidly colonize. [ABSTRACT FROM AUTHOR]

In the dairy region of northern Victoria, Australia, the performance of temperate perennial dairy pastures is often poor over summer due to a combination of high temperatures and limited water availability that can restrict dry matter production and plant survival. This review summarizes published and unpublished research on perennial ryegrass, mostly undertaken in the northern Victoria region over the past decade, to help determine its future role in this environment. It includes information from a series of field experiments or case studies where the effects of heat and restricted irrigation on the growth and nutritive characteristics of perennial ryegrass were examined. This research involved investigations on whether plant survival under the stressed experimental conditions could be influenced by plant genotype, irrigation, and grazing management strategies, as well as by the presence of endophyte. In conclusion, it was difficult to identify any irrigation, grazing management or plant genotype effect that consistently improved the performance of perennial ryegrass in the hot, dry summers of northern Victoria, Australia. The incidences of extreme heat events and low water availability in this region are increasing, and the role of C3 perennial grasses as major suppliers of feed for dairy cows is diminishing. A major focus for the dairy industry in this region is now to identify new farming systems and alternative species that may be better adapted to the climate environment than perennial ryegrass, as well as be capable of adapting to year‐to‐year variations in irrigation water supply. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is an important turfgrass and gramineous forage widely grown in temperate regions around the world. However, its perennial nature leads to the inevitable exposure of perennial ryegrass to various environmental stresses on a seasonal basis and from year to year. Like other plants, perennial ryegrass has evolved sophisticated mechanisms to make appropriate adjustments in growth and development in order to adapt to the stress environment at both the physiological and molecular levels. A thorough understanding of the mechanisms of perennial ryegrass response to abiotic stresses is crucial for obtaining superior stress-tolerant varieties through molecular breeding. Over the past decades, studies of perennial ryegrass at the molecular and genetic levels have revealed a lot of useful information to understand the mechanisms of perennial ryegrass adaptation to an adverse environment. Unfortunately, molecular mechanisms by which perennial ryegrass adapts to abiotic stresses have not been reviewed thus far. In this review, we summarize the recent works on the genetic and molecular mechanisms of perennial ryegrass response to the major abiotic stresses (i.e., drought, salinity, and extreme temperatures) and discuss new directions for future studies. Such knowledge will provide valuable information for molecular breeding in perennial ryegrass to improve stress resistance and promote the sustainability of agriculture and the environment. [ABSTRACT FROM AUTHOR]

Suppression of the chlorophyll a (Chl a) Mg‐dechelatase gene, SGR/NYE1, blocks the degradation of Chl a, resulting in a 'stay‐green' trait. In this study, we investigated the effect of Chl a catabolism on plant heat‐induced leaf senescence in perennial ryegrass (Lolium perenne L.). Under heat stress, the LpSGR‐RNAi lines not only lost the stay‐green phenotype but also showed accelerated leaf senescence with increased chloroplast disruption, more loss of photosystem (PS) proteins, lower PSⅡ quantum yields, higher levels of energy dissipation, increased accumulation of reactive oxygen species (ROS) and lower ROS‐scavenging enzyme activities. Transcriptome analysis revealed that the suppression of LpSGR downregulated genes encoding PS proteins and ROS‐scavenging enzymes and upregulated those encoding ROS‐generation enzymes under heat stress. To account for the possible side‐effects resulting from constitutive suppression of LpSGR on plant growth and heat tolerance, we constructed an ethanol‐inducible RNAi vector to suppress LpSGR functions. In the absence of ethanol induction, these lines exhibited the same growth and heat tolerance as the wildtype (WT). Upon ethanol induction, the transgenic lines showed compromised heat tolerance and a postharvest stay‐green phenotype. Taken together, SGR‐mediated Chl a catabolism is required for plant heat tolerance. SUMMARY STATEMENT: Here, we report that blocking SGR‐mediated Chl a degradation leads to severe photo‐damage under heat stress conditions. Repressing LpSGR in an inducible manner can retain the stay‐green trait with no compromised heat tolerance in perennial ryegrass (Lolium perenne). [ABSTRACT FROM AUTHOR]

In transition areas, cool season turfgrasses are overseeded in autumn to maintain the high quality of dormant warm season turfgrasses, while in spring several agronomic methods (scalping, coring, topdressing, verticutting, irrigation, and targeted fertilization) or chemical desiccation are adopted to remove the cool season turfgrasses from the stand. To reduce chemical applications, several methods of "thermal weeding" have been experimented with, but little is known about these methods in zoysiagrass (Zoysia spp. Willd) spring transition. A study was conducted at the University of Pisa, Italy, on Manila grass (Zoysia matrella (L.) Merr., cv "Diamond") (Zm) overseeded with perennial ryegrass (Lolium perenne L.) (Lp) with the aim of comparing different methods of cool season grass suppression (scalping and hot foam) and different application rates of nitrogen. To assess treatment effect, green cover, turf quality, turf color, shoot density, and some vegetation indices (GLI, DGCI and NDVI) were determined. An average green cover of at least 90% was obtained on all plots seven weeks after the treatments. While scalping had minor effects on turf appearance and on polystand composition, hot foam had a stronger effect on turf color, green cover, and turf quality in the weeks following application. Once it had recovered from the hot foam treatments, the turf had a greater number of Zm shoots and a relevant reduction of Lp shoots. The hot foam was very effective in suppressing Lp while maintaining Zm recovery capacity. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of cultivar, nitrogen (N) rate, and biostimulant application on the chemical composition of the aboveground biomass of perennial ryegrass (Lolium perenne L.). A small-area field experiment was established in the Agricultural Experiment Station in Tomaszkowo (53°42′40.8″ N 20°26′04.7″ E, north-eastern Poland). The experiment had a split-plot design with three replications, and the experimental variables were as follows: (i) perennial ryegrass cultivar: Bajka and Baronka, (ii) N fertilizer rate: 0, 120, 240 kg N ha−1, (iii) application of biostimulants: Blatt Boden-Foliar (BB-F) and Blatt Boden-Foliar + Blatt Boden-Multical (BB-F + BB-M). This study demonstrated that the tetraploid cultivar Baronka had a more desirable chemical composition than the diploid cultivar Bajka. The biomass of cv. Baronka had a higher content of CP, CF, and K, and it was characterized by higher leaf greenness (SPAD) values. Nitrogen fertilization considerably increased the content of CP, P, and K, and leaf greenness (SPAD) values in both cultivars, and the noted increase was higher when N was applied at 240 kg ha−1. The N fertilizer rate of 120 kg ha−1 led to a significant decrease in the average Ca content of plants, whereas the N fertilizer rate of 240 kg ha−1 had no significant effect on Ca concentration. The tested biostimulants significantly affected the chemical composition of perennial ryegrass biomass, and their influence was greater when they were applied in combination. The foliar application of Blatt Boden-Foliar and Blatt Boden-Multical increased the content of CP, P, and chlorophyll in perennial ryegrass leaves, whereas it decreased the accumulation of CF, K, and Ca in plants. The analyzed biostimulants had a positive effect on the chemical composition of perennial ryegrass biomass. This is an important practical consideration because high-quality green fodder for livestock can be produced while minimizing the use of mineral fertilizers and adverse environmental impacts. [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]

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]

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]

Loss of chlorophyll and oxidative damage co-occur during heat-induced leaf senescence. This study aimed to determine the functions of a chlorophyll catabolic gene, NON-YELLOW COLOURING 1 (NYC1)-like (NOL), in regulating heat-induced leaf senescence and to characterize antioxidant roles of a chlorophyll derivative, sodium copper chlorophyllin (SCC), in suppressing heat-induced leaf senescence. In two separate experiments, one by comparing NOL RNAi transgenic and wild-type plants, and the other by analysing the effects of SCC treatment, perennial ryegrass (Lolium perenne) was exposed to heat stress (38/35 °C, day/night) or optimal temperature (25/20 °C). Results showed that both knock down of LpNOL and application of SCC suppressed heat-induced leaf senescence, as manifested by increased chlorophyll content, reduced electrolyte leakage, down-regulation of chlorophyll-catabolic genes and senescence-related genes, as well as enhanced antioxidant capacity in the peroxidase pathway for H2O2 scavenging. Ex vivo SCC incubation protected membranes from H2O2 damage in mesophyll protoplasts of perennial ryegrass. The suppression of leaf senescence by knocking down NOL or chlorophyllin application was associated with enhanced chlorophyll accumulation playing antioxidant roles in protecting leaves from heat-induced oxidative damage. [ABSTRACT FROM AUTHOR]

During late spring and early summer, perennial ryegrass (Lolium perenne L.) produces reproductive structures (i.e., culm and inflorescence), that decrease turf quality due to stemminess (i.e., culm remaining) after mowing. Research is required to understand the impact of management practices on visible culm and inflorescence presence. Field experiments were conducted to evaluate perennial ryegrass culm, inflorescence, and turf canopy responses due to various nitrogen (N) fertilization levels, scalping timings and heights. In Experiment 1, N fertilization rates ≥24 kg N ha−1 applied in early May with a slow‐release fertilizer prior to peak flowering (i.e., late May to early June) visibly decreased culms and inflorescences compared with 0 and 12 kg N ha−1. Higher N fertilizer levels, especially 98 kg N ha−1, also resulted in fewer necrotic culms remaining later in the summer along with greater overall turf quality and reduced weed cover. In Experiment 2, scalping perennial ryegrass at 3.8 or 5.1 cm on 25 May, the closest proximity prior to peak flowering, provided the lowest area under the curve (AUC) of green flowering culms. Scalping during or after peak flowering resulted in similar AUC values compared with nonscalped (7.6 cm) turf but did decrease the presence of necrotic culms later in summer to help improve turf quality. Overall, N fertility with a slow‐release fertilizer or a well‐timed scalping influences spring culm and inflorescence density and necrotic culm stemminess in perennial ryegrass turf systems. Additional research on physiological responses, such as carbohydrate partitioning, to these management practices is required. Core Ideas: Spring N fertilization (≥24 kg N ha−1) decreases perennial ryegrass flowering culms.Scalping timing and height influence subsequent culm and inflorescence density.Necrotic culms in July and August were decreased by scalping in late May, June, or early July.A spring preemergence herbicide application should be included to reduce weed encroachment when scalping. [ABSTRACT FROM AUTHOR]

Argentine stem weevil adults (ASW, Listronotus bonariensis) feed on the leaves of agricultural grasses and their larvae mine the pseudostem, causing extensive damage that can result in plant death. Plants emit volatiles that serve as signals to host-searching insects and these odours can be altered by both herbivory and fungal endophyte-infection. This study investigated whether ASW adults utilise olfaction to identify their host plants, perennial ryegrass (Lolium perenne), and if conspecific herbivory or the presence of Epichloë festucae var. lolii fungal endophytes (strain wild-type or AR1) influenced such responses. Results from olfactometer bioassays established that ASW adults were able to utilise their olfactory response to orient towards volatiles released by perennial ryegrass and further, the weevils displayed a preference for plants previously damaged by conspecific weevils. However, there was no evidence that weevils had the ability to distinguish between endophyte-infected and endophyte-free plants using olfaction alone. Using a push–pull extraction technique, thirteen volatile compounds were identified in the blend released by perennial ryegrass. Endophyte and herbivory were found to alter these volatile compounds and quantities emitted by this forage grass. This study suggests that despite observing differences in the plant volatile blend, ASW do not perceive endophyte (wild-type and AR1) using olfaction alone and must rely on other cues, e.g. contact chemoreception or post-ingestional malaise, to detect the presence of a bioactive endophyte in an otherwise acceptable host plant. [ABSTRACT FROM AUTHOR]

Aim: Potassium (K) is a key determinant for plant development and productivity. However, more than 90% of K in the soil exists in an insoluble form. K‐solubilizing microbes play an important role in the transformation of insoluble K. Thus, the objective of this study was to evaluate K‐dissolving ability of Aspergillus aculeatus (F) and growth‐promoting properties in perennial ryegrass. Methods and Results: Perennial ryegrass inoculated with A. aculeatus exhibited enhanced soluble K accompanied with higher growth rate and turf quality, compared with the noninoculated regimen. In addition, A. aculeatus also played a primary role in increasing chlorophyll content and photosynthetic capacity of the plant exposed to LK+F (K‐feldspar plus A. aculeatus) treatment, compared with the CK (control, no K‐feldspar and A. aculeatus), F (only A. aculeatus) and LK (only K‐feldspar) groups. Furthermore, the antioxidase activities (CAT and POD) were significantly increased while the oxidative damage (EL and MDA) was dramatically decreased in the LK+F group compared to the LK (K‐feldspar) group. Finally, in perennial ryegrass leaves, the genes expression levels of HAK8, HAK12 and HKT18 were obviously elevated in the LK+F group, compared to the CK, F and LK groups. Conclusion: We concluded that A. aculeatus could solubilize K from bound form and be considered as K‐solubilizing biofertilizer through supplementing K in soil. Significance and Impact of the Study: Aspergillusaculeatus has the potential to be used as a biofertilizer in sustainable agriculture. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the influence of the different proportion of perennial ryegrass (Lolium perenne L.) in the meadow sward on its fodder value and daily weight gain of Highland cattle. The research was carried out on meadow sward with natural undergrowth that was cultivated by sowing perennial ryegrass. When preparing the sward for sowing, around 40% of it was damaged with a rotary tiller. The sowing rate for perennial ryegrass seeds was varied and amounted to 5, 10 and 15 kg ha−1. As a result, the following treatments of meadow sward were obtained and distinguished: semi-natural sward without sowing as the control, and three experimental treatments with approximately 18, 36 and 55% share of perennial ryegrass in the meadow sward. The animals were kept in a cowshed. In the nutritional part, the impact of feeding the obtained sward on the daily weight gain of Highland bulls and heifers was assessed. The obtained results showed higher gains in both bulls and heifers fed with sward from grasslands with a greater proportion of perennial ryegrass. The weight gain of the animals resulted from the nutrition, i.e. the quality of the feed obtained from the experimental objects. During the control fattening period, the bulls' average daily weight gain ranged from 649 g to 714 g, while for heifers 556 g to 598 g. Statistical significance (P≤0.05) in body weight gains in both bulls and heifers was shown already at 36% of perennial ryegrass in the meadow sward. [ABSTRACT FROM AUTHOR]

Autumn closing date (CD) in intensive pasture‐based systems influences spring herbage availability. Little is known about the impact of earlier closing of swards in autumn on sward structure. A two‐year experiment was undertaken to investigate the impact of five CD on herbage production, leaf extension rate (LER), leaf senescence rates (LSR), sward free leaf lamina (FLL) content and the production and survival of tillers over winter and into spring. The five CD ranges were October 1–15 (CD1), October 16–30 (CD2), October 31––November 14 (CD3), November 15–29 (CD4), November 30–December 14 (CD5) and sward measurements were made on four measurement dates (MD): December 11 (MD1), January 6 (MD2), January 27 (MD3) and prior to spring defoliation (MD4). Thirty perennial ryegrass tillers were measured until the first defoliation in spring (average 1 March). Herbage mass was greatest in early CD and tillers had greater LER and LSR (4.6 and 4.5 mm tiller−1 day−1 respectively) compared to swards with a later CD (3.2 and 2.3 mm tiller−1 day−1 respectively). Early CD had greater parent and daughter tiller mortality than later CD (parent tiller mortality 1.1 and 0.3 ± 0.19 tillers; daughter tiller mortality 1.1 and 0.3 ± 0.27 tillers respectively). Early CD also had greater LER and LSR in daughter tillers (2.6 and 1.5 mm tiller−1 day−1, respectively) compared to late (1.5 and 0.5 mm tiller−1 day−1, respectively). Earlier closing of sward increased herbage mass in spring, however, there were negative implications, such as increased LSR and tiller mortality. [ABSTRACT FROM AUTHOR]

Bleaching of young leaf tissue is a common response to the herbicide mesotrione and varies from one application to another. To better elucidate factors that may contribute to perennial ryegrass (Lolium perenne L.) phytotoxicity from mesotrione, studies were conducted at Blacksburg, VA. Continuous field monitoring of temperature, humidity, solar radiation, soil moisture, and leaf wetness was used to elucidate environmental conditions that led to perennial ryegrass injury by mesotrione applied at 0.14 kg a.i. ha−1. The study found that 2 of 17 weekly treatments caused unacceptable perennial ryegrass injury at two field sites. Ten‐day temporal trends prior to mesotrione treatment showed that temperature, for one injury event, and volumetric soil water content, for the other injury event, were exclusively correlated to visually and digitally assessed perennial ryegrass injury. Both instances suggest that alleviation of suboptimal temperature or moisture with more optimal growing conditions influenced the turf injury response. Additional studies in growth chambers showed that carotenoid levels and turf phytotoxicity were strongly temperature dependent and followed a quadratic response with peak injury occurring at perennial ryegrass growth optima. Carotenoid levels decreased and perennial ryegrass injury increased in response to increased mesotrione rate. These data suggest that mesotrione is more likely to injure perennial ryegrass turf when used at higher rates and under conditions of rapid turfgrass growth. [ABSTRACT FROM AUTHOR]

In northern Victoria, Australia, perennial pastures for the dairy industry have historically been based on perennial ryegrass. However, perennial ryegrass does not perform well under high summer temperatures and water stress. We investigated irrigation, renovation and grazing management strategies for improving the resilience and survival of perennial ryegrass over summer on two farms in northern Victoria over 2.5 years. At each farm, two irrigation bays were sown in March 2015. During summer (late December–mid-March), one bay was not irrigated and the other bay received a single mid-summer irrigation. Each bay was sown to 12 ryegrass cultures: five cultivars of perennial ryegrass either oversown or not oversown, and two oversown cultivars of short-lived ryegrass (SLRG). A mid-summer grazing treatment was applied to one-half of each of these plots. All plots at both sites received the same irrigation and grazing management at other times of the year. There were significant variations in dry matter (DM) production, nutritive characteristics and plant frequencies across sites and seasons, and across renovation, irrigation and grazing management strategies. Cumulative DM yields were higher in the perennial ryegrass than the SLRG cultivars. Summer DM removal was very low at both sites; the ungrazed plots recovered and produced more DM in the following cooler period than the grazed plots in the first year but not the second. Metabolisable energy concentration was higher for perennial ryegrass than SLRG cultivars and was also higher in plots that had been grazed over the summer. There were large differences in plant frequency between species, and there were some differences among perennial ryegrass cultivars. The effect of summer grazing on plant frequency varied at each site and was not significant within an irrigation treatment. This research confirms that perennial ryegrass is not well suited to the hot, dry summers of northern Victoria and suggests that, under conditions of limited summer irrigation, farmers should focus on plant survival rather than summer yield if they are to maximise annual DM production. The effects of restricted irrigation and summer grazing were examined in plots of perennial and short-lived ryegrass cultivars at two district sites in northern Victoria, Australia. Responses varied across sites, seasons and cultures. Perennial ryegrasses performed better than short-lived ryegrasses, but dry matter production was low and plant frequency was a better indicator of plant resilience to these conditions. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine and compare the sensitivity of new high yield Bulgarian varieties of perennial ryegrass (Lolium perenne L.) - Harmoniya, Tetrany and Tetramis to glyphosate in laboratory conditions. The effect of three doses of glyphosate - 360, 720 and 1440 g a.i./ha applied in the growth stage tillering (BBCH - 22-23) on perennial ryegrass on the dynamics of plant growth and formed fresh biomass in g per plant was studied. Genotypic differences were observed between the studied varieties of perennial ryegrass to glyphosate. With a relatively high sensitivity to glyphosate conditionally can be determined diploid variety Harmoniya in which the depression coefficients (B) on the dynamics of growth and accumulation of fresh biomass are in the range from -5.7 to - 4.7, while for tetraploids Tetrany (B) (average) is in the range of -3.3 to -3.9 and for Tetramis (B) (average) is within limits from -3.2 to -3.9, they have relatively high tolerance to glyphosate and can be used as components in future programs. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is considered the most important pasture species in temperate agriculture, with over six million hectares of sown area in Australia alone. However, perennial ryegrass has poor persistence in some environments because of low tolerance to a range of both abiotic and biotic stresses. To breed perennial ryegrass, cultivars with greater persistence and productivity may require evaluation of genotypes over a number of years. Persistence assessment in pasture breeding depends on manual ground cover estimation or counting the number of surviving plants or tillers in a known area. These methods are subjective and labour intensive, which may limit data collection in large‐scale breeding programs. With the rapid development of sensors and image processing algorithms, image‐based high‐throughput phenotyping (HTP) is becoming commonplace in the breeding of major food crops. Image‐based HTP approaches consist of the deployment of a wide range of sensors on ground‐based or airborne platforms and data analysed through image processing pipelines. Image‐based HTP shows high potential for use in pasture phenotyping in breeding programs and may be able to reduce timeframes for releasing new cultivars. Moreover, existing image‐based HTP approaches could be further developed to include precise tools for phenotyping pasture persistence traits such as pasture senescence, botanical composition, pathogen and pest resistance. In this study, we reviewed existing image‐based HTP approaches in precision agriculture and discussed their feasibility for perennial ryegrass persistence estimation in pasture breeding. Although the paper focuses on application in perennial ryegrass, the principles equally apply to other perennial forage species. [ABSTRACT FROM AUTHOR]

Despite the progress made in DNA sequencing over the last decade, reconstructing telomere-to-telomere genome assemblies of large and repeat-rich eukaryotic genomes is still difficult. More accurate basecalls or longer reads could address this issue, but no current sequencing platform can provide both simultaneously. Perennial ryegrass (Lolium perenne L.) is an example of an important species for which the lack of a reference genome assembly hindered a swift adoption of genomics-based methods into breeding programs. To fill this gap, we optimized the Oxford Nanopore Technologies' sequencing protocol, obtaining sequencing reads with an N50 of 62 kb—a very high value for a plant sample. The assembly of such reads produced a highly complete (2.3 of 2.7 Gb), correct (QV 45), and contiguous (contig N50 and N90 11.74 and 3.34 Mb, respectively) genome assembly. We show how read length was key in determining the assembly contiguity. Sequence annotation revealed the dominance of transposable elements and repeated sequences (81.6% of the assembly) and identified 38,868 protein coding genes. Almost 90% of the bases could be anchored to seven pseudomolecules, providing the first high-quality haploid reference assembly for perennial ryegrass. This protocol will enable producing longer Oxford Nanopore Technology reads for more plant samples and ushering forage grasses into modern genomics-assisted breeding programs. [ABSTRACT FROM AUTHOR]

The nutrient use efficiency of perennial ryegrass (Lolium perenne L.) (PR) and white clover (Trifolium repens L.) (WC) cultivars can affect the grass-legume compatibility of different cultivar combinations, thus impacting the sustainability of animal production systems, especially on marginal soils. The objective of this work was to evaluate N, P, and K absorption efficiency (NAE, PAE, and KAE) and use efficiency (NUE, PUE, and KUE). This study included two experiments with the same full factorial treatment structure (4 PR cultivars x 3 WC cultivars) in a randomized complete block design under field conditions and a completely randomized pot design. The field cutting experiment was carried out on sites with two contrasting soil depths and the pot experiment was conducted under shade conditions. Results showed nonsignificant (P > 0.05) factor interactions for DM yield and both nutrient absorption and use efficiency. The NAE and PAE of PR 'Extreme' and 'Bealey' were higher under field conditions than pot conditions. In the field experiment, NAE of WC 'Will' (2.33 kg DM ha-1)/mg N kg-1)) tended to be similar (P < 0.05) to other cultivars in deep soil, but was significantly higher (P < 0.001) than 'Ladino' and 'Bounty' in shallow soil (0.70 kg DM ha-1)/mg kg-1). The evaluation of NUE and PUE under field conditions and KUE under pot conditions showed that PR 'Bealey' and WC 'Ladino' reached higher values. In conclusion, results showed a cultivar effect on nutrient use efficiency in PR/WC mixtures, which had an impact on PRWC compatibility, mainly due to the higher absorption efficiency of PR 'Bealey' and WC 'Will', both of which exhibited the highest degree of compatibility for total DM yield. [ABSTRACT FROM AUTHOR]

As a conserved microRNA (miRNA) family in plants, miR408 is known to be involved in different abiotic stress responses, including drought. Interestingly, some studies indicated a species- and/or cultivar-specific drought-responsive characteristic of miR408 in plant drought stress. Moreover, the functions of miR408 in perennial grass species are unknown. In this study, we investigated the role of miR408 in perennial ryegrass (Lolium perenne L.) by withholding water for 10 days for both wild type and transgenic plants with heterologous expression of rice (Oryza sativa L.) miR408 gene, Os-miR408. The results showed that transgenic perennial ryegrass plants displayed morphological changes under normal growth conditions, such as curl leaves and sunken stomata, which could be related to decreased leaf water loss. Moreover, transgenic perennial ryegrass exhibited improved drought tolerance, as demonstrated by maintaining higher leaf relative water content (RWC), lower electrolyte leakage (EL), and less lipid peroxidation compared to WT plants under drought stress. Furthermore, the transgenic plants showed higher antioxidative capacity under drought. These results showed that the improved drought tolerance in Os-miR408 transgenic plants could be due to leaf morphological changes favoring the maintenance of water status and to increased antioxidative capacity protecting against the reactive oxygen species damages under stress. These findings implied that miR408 could serve as a potential target for genetic manipulations to engineer perennial grass plants for improved water stress tolerance. [ABSTRACT FROM AUTHOR]