scholarly journals Natural variation of physiological traits, molecular markers, and chlorophyll catabolic genes associated with heat tolerance in perennial ryegrass accessions

2020 ◽  
Author(s):  
Bin Xu ◽  
Jing Zhang ◽  
Hui Li ◽  
Yiwei Jiang ◽  
Huibin Li ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Ssr Markers ◽  
Heat Tolerance ◽  
Perennial Ryegrass ◽  
Physiological Traits ◽  
Grass Species ◽  
Cool Season ◽  
Catabolic Genes ◽  
Heat Tolerant ◽  
Cool Season Grass

Abstract Background: Identification of genetic diversity in heat tolerance and associated traits is of great importance for improving heat tolerance in cool-season grass species. The objectives of this study were to determine genetic variations in heat tolerance associated with phenotypic and physiological traits and to identify molecular markers associated with heat tolerance in a diverse collection of perennial ryegrass (Lolium perenne L.). Results: Plants of 98 accessions were subjected to heat stress (35/30 ℃, day/night) or optimal growth temperature (25/20 ℃) for 24 d in growth chambers. Overall heat tolerance of those accessions was ranked by principal component analysis (PCA) based on eight phenotypic and physiological traits. Among these traits, electrolyte leakage (EL), chlorophyll content (Chl), relative water content (RWC) had high correlation coefficients (−0.858, 0.769, and 0.764, respectively) with the PCA ranking of heat tolerance. We also found expression levels of four Chl catabolic genes (CCGs), including LpNYC1, LpNOL, LpSGR, and LpPPH, were significant higher in heat sensitive ryegrass accessions then heat tolerant ones under heat stress. Furthermore, 66 pairs of simple sequence repeat (SSR) markers were used to perform association analysis based on the PCA result. The population structure of ryegrass can be grouped into three clusters, and accessions in cluster C were relatively more heat tolerant than those in cluster A and B. SSR markers significantly associated with above-mentioned traits were identified (R2>0.05, p <0.01)., including two pairs of markers located on chromosome 4 in association with Chl content and another four pairs of markers in association with EL. Conclusion: The result not only identified useful physiological parameters, including EL, Chl content, and RWC, and their associated SSR markers for heat-tolerance breeding of perennial ryegrass, but also highlighted the involvement of Chl catabolism in ryegrass heat tolerance. Such knowledge is of significance for heat-tolerance breeding and heat tolerance mechanisms in perennial ryegrass as well as in other cool-season grass species.

scholarly journals Natural variation of physiological traits, molecular markers, and chlorophyll catabolic genes associated with heat tolerance in perennial ryegrass accessions

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jing Zhang ◽  
Hui Li ◽  
Yiwei Jiang ◽  
Huibin Li ◽  
Zhipeng Zhang ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Ssr Markers ◽  
Heat Tolerance ◽  
Perennial Ryegrass ◽  
Physiological Traits ◽  
Grass Species ◽  
Cool Season ◽  
Catabolic Genes ◽  
Heat Tolerant ◽  
Cool Season Grass

Abstract Background Identification of genetic diversity in heat tolerance and associated traits is of great importance for improving heat tolerance in cool-season grass species. The objectives of this study were to determine genetic variations in heat tolerance associated with phenotypic and physiological traits and to identify molecular markers associated with heat tolerance in a diverse collection of perennial ryegrass (Lolium perenne L.). Results Plants of 98 accessions were subjected to heat stress (35/30 °C, day/night) or optimal growth temperature (25/20 °C) for 24 d in growth chambers. Overall heat tolerance of those accessions was ranked by principal component analysis (PCA) based on eight phenotypic and physiological traits. Among these traits, electrolyte leakage (EL), chlorophyll content (Chl), relative water content (RWC) had high correlation coefficients (− 0.858, 0.769, and 0.764, respectively) with the PCA ranking of heat tolerance. We also found expression levels of four Chl catabolic genes (CCGs), including LpNYC1, LpNOL, LpSGR, and LpPPH, were significant higher in heat sensitive ryegrass accessions then heat tolerant ones under heat stress. Furthermore, 66 pairs of simple sequence repeat (SSR) markers were used to perform association analysis based on the PCA result. The population structure of ryegrass can be grouped into three clusters, and accessions in cluster C were relatively more heat tolerant than those in cluster A and B. SSR markers significantly associated with above-mentioned traits were identified (R2 > 0.05, p < 0.01)., including two pairs of markers located on chromosome 4 in association with Chl content and another four pairs of markers in association with EL. Conclusion The result not only identified useful physiological parameters, including EL, Chl content, and RWC, and their associated SSR markers for heat-tolerance breeding of perennial ryegrass, but also highlighted the involvement of Chl catabolism in ryegrass heat tolerance. Such knowledge is of significance for heat-tolerance breeding and heat tolerance mechanisms in perennial ryegrass as well as in other cool-season grass species.

scholarly journals Natural variation of physiological traits, molecular markers, and chlorophyll catabolic genes associated with heat tolerance in perennial ryegrass accessions

2020 ◽  
Author(s):  
Jing Zhang ◽  
Hui Li ◽  
Yiwei Jiang ◽  
Huibin Li ◽  
Zhipeng Zhang ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Ssr Markers ◽  
Heat Tolerance ◽  
Perennial Ryegrass ◽  
Physiological Traits ◽  
Grass Species ◽  
Cool Season ◽  
Catabolic Genes ◽  
Heat Tolerant ◽  
Cool Season Grass

Abstract Background: Identification of genetic diversity in heat tolerance and associated traits is of great importance for improving heat tolerance in cool-season grass species. The objectives of this study were to determine genetic variations in heat tolerance associated with phenotypic and physiological traits and to identify molecular markers associated with heat tolerance in a diverse collection of perennial ryegrass (Lolium perenne L.).Results: Plants of 98 accessions were subjected to heat stress (35/30 ℃, day/night) or optimal growth temperature (25/20 ℃) for 24 d in growth chambers. Overall heat tolerance of those accessions was ranked by principal component analysis (PCA) based on eight phenotypic and physiological traits. Among these traits, electrolyte leakage (EL), chlorophyll content (Chl), relative water content (RWC) had high correlation coefficients (−0.858, 0.769, and 0.764, respectively) with the PCA ranking of heat tolerance. We also found expression levels of four Chl catabolic genes (CCGs), including LpNYC1, LpNOL, LpSGR, and LpPPH, were significant higher in heat sensitive ryegrass accessions then heat tolerant ones under heat stress. Furthermore, 66 pairs of simple sequence repeat (SSR) markers were used to perform association analysis based on the PCA result. The population structure of ryegrass can be grouped into three clusters, and accessions in cluster C were relatively more heat tolerant than those in cluster A and B. SSR markers significantly associated with above-mentioned traits were identified (R2>0.05, p <0.01)., including two pairs of markers located on chromosome 4 in association with Chl content and another four pairs of markers in association with EL.Conclusion: The result not only identified useful physiological parameters, including EL, Chl content, and RWC, and their associated SSR markers for heat-tolerance breeding of perennial ryegrass, but also highlighted the involvement of Chl catabolism in ryegrass heat tolerance. Such knowledge is of significance for heat-tolerance breeding and heat tolerance mechanisms in perennial ryegrass as well as in other cool-season grass species.

scholarly journals Natural Variation of Physiological Traits, Molecular Markers, and Chlorophyll Catabolic Genes Associated With Heat Tolerance in Perennial Ryegrass Accessions

2020 ◽  
Author(s):  
Bin Xu ◽  
Jing Zhang ◽  
Hui Li ◽  
Yiwei Jiang ◽  
Huibin Li ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Ssr Markers ◽  
Heat Tolerance ◽  
Perennial Ryegrass ◽  
Principal Component ◽  
Physiological Traits ◽  
Grass Species ◽  
Cool Season ◽  
Catabolic Genes ◽  
Cool Season Grass

Abstract Background: Identification of genetic diversity in heat tolerance and associated traits is of great importance for improving heat tolerance in cool-season grass species. The objectives of this study were to determine genetic variations in heat tolerance associated with phenotypic and physiological traits and to identify molecular markers associated with heat tolerance in a diverse collection of perennial ryegrass (Lolium perenne L.). Results: Plants of 98 accessions were subjected to heat stress (35/30 ℃, day/night) or optimal growth temperature (25/20 ℃) for 24 d in growth chambers. Overall heattolerance of those accessions was ranked by principal component analysis (PCA) based on eight phenotypic and physiological traits. Among these traits, electrolyte leakage (EL), chlorophyll content (Chl), relative water content (RWC) had high correlation coefficients (−0.858, 0.769, and 0.764, respectively) with the PCA ranking of heat tolerance. We also found expression levels of four Chl catabolic genes (CCGs), including LpNYC1, LpNOL, LpSGR, and LpPPH, were closely related to the heat tolerance of ryegrass accessions. Furthermore, 66 pairs of simple sequence repeat (SSR) markers were used to perform association analysis based on the PCA result. The population structure of ryegrass can be grouped into three clusters, and accessions in cluster C were relatively more heat tolerant than those in cluster A and B. SSR markers significantly associated with above-mentioned traits were identified (R2>0.05, p<0.01)., including two pairs of markers located on chromosome 4 in association with Chl content and another four pairs of markers in association with EL.Conclusion:The result not only identified useful physiological parameters, including EL, Chl content, and RWC, and their associated SSR markers for heat-tolerance breeding of perennial ryegrass, but also highlighted the involvement of Chl catabolism in ryegrass heat tolerance. Such knowledge is of significance for heat-tolerance breeding and heat tolerance mechanisms in perennial ryegrass as well as in other cool-season grass species.

scholarly journals Impact of Overseeded Grass Species, Seeding Rate and Seeding Time on Establishment and Persistence in Bermudagrass

2011 ◽  
Vol 29 (2) ◽  
pp. 75-80
Author(s):  
Thomas Serensits ◽  
Matthew Cutulle ◽  
Jeffrey F. Derr
Keyword(s):  
Perennial Ryegrass ◽  
Ground Cover ◽  
Italian Ryegrass ◽  
Grass Species ◽  
Percent Cover ◽  
Seeding Rate ◽  
Cool Season ◽  
Seeding Time ◽  
One Year ◽  
Cool Season Grass

Abstract Cool-season grass species are often overseeded into bermudagrass turf for both aesthetics and functionality during the winter months. When the overseeded grass persists beyond the spring, however, it becomes a weed. Experiments were conducted to evaluate overseeded grass species and seeding rate on turf cover during the fall, spring, and summer. The ability of perennial ryegrass, Italian ryegrass, and hybrid bluegrass to then persist in bermudagrass one year after seeding was determined. Both perennial ryegrass and Italian ryegrass produced acceptable ground cover in the spring after fall seeding. Hybrid bluegrass did not establish well, resulting in unacceptable cover. Perennial ryegrass generally had the most persistence one year after seeding, either because of the survival of plants through the summer or because of new germination the following fall. The highest cover seen one year after seeding was 24% with perennial ryegrass in the 2005 trial. Maximum cover seen with Italian ryegrass and hybrid bluegrass 12 months after seeding was 19 and 8%, respectively. Seeding perennial or Italian ryegrass in February achieved acceptable cover in spring in the first trial but not the second. Persistence the following fall, however, was greater in the second trial, suggesting new germination. Percent cover 12 months after seeding tended to increase as the seeding rate increased, also suggesting new germination the following fall. Although quality is lower with Italian ryegrass compared to perennial ryegrass, it transitions out easier than perennial ryegrass, resulting in fewer surviving plants one year after fall seeding.

scholarly journals Persistence of Overseeded Cool-Season Grasses in Bermudagrass Turf

2011 ◽  
Vol 2011 ◽  
pp. 1-8
Author(s):  
Thomas Serensits ◽  
Matthew Cutulle ◽  
Jeffrey F. Derr
Keyword(s):  
Perennial Ryegrass ◽  
Ground Cover ◽  
Italian Ryegrass ◽  
Grass Species ◽  
Annual Ryegrass ◽  
Treatment Rate ◽  
Seeding Rate ◽  
Cool Season ◽  
One Year ◽  
Cool Season Grass

Cool-season grass species are commonly overseeded into bermudagrass turf for winter color. When the overseeded grass persists beyond the spring; however, it becomes a weed. The ability of perennial ryegrass, Italian (annual) ryegrass, intermediate ryegrass, and hybrid bluegrass to persist in bermudagrass one year after seeding was determined. Perennial ryegrass, intermediate ryegrass, and Italian ryegrass produced acceptable ground cover in the spring after fall seeding. Hybrid bluegrass did not establish well, resulting in unacceptable cover. Perennial ryegrass generally persisted the most one year after seeding, either because of summer survival of plants or because of new germination the following fall. Plant counts one year after seeding were greater in the higher seeding rate treatment compared to the lower seeding treatment rate of perennial ryegrass, suggesting new germination had occurred. Plant counts one year after seeding plots with intermediate ryegrass or Italian ryegrass were attributed primarily to latent germination and not summer survival. Applications of foramsulfuron generally did not prevent overseeded species stand one year after seeding, supporting the conclusion of new germination. Although quality is less with intermediate ryegrass compared to perennial ryegrass, it transitions out easier than perennial ryegrass, resulting in fewer surviving plants one year later.

Use of tall fescue EST-SSR markers in phylogenetic analysis of cool-season forage grasses

Genome ◽  
2005 ◽  
Vol 48 (4) ◽  
pp. 637-647 ◽  
Author(s):  
M A. Rouf Mian ◽  
Malay C Saha ◽  
Andrew A Hopkins ◽  
Zeng-Yu Wang
Keyword(s):  
Phylogenetic Analysis ◽  
Ssr Markers ◽  
Tall Fescue ◽  
Related Species ◽  
Grass Species ◽  
Forage Grass ◽  
Forage Grasses ◽  
Cool Season ◽  
Phylogenetic Relations ◽  
Wide Range

Microsatellites or simple sequence repeats (SSRs) are highly useful molecular markers for plant improvement. Expressed sequence tag (EST)-SSR markers have a higher rate of transferability across species than genomic SSR markers and are thus well suited for application in cross-species phylogenetic studies. Our objectives were to examine the amplification of tall fescue EST-SSR markers in 12 grass species representing 8 genera of 4 tribes from 2 subfamilies of Poaceae and the applicability of these markers for phylogenetic analysis of grass species. About 43% of the 145 EST-SSR primer pairs produced PCR bands in all 12 grass species and had high levels of polymorphism in all forage grasses studied. Thus, these markers will be useful in a variety of forage grass species, including the ones tested in this study. SSR marker data were useful in grouping genotypes within each species. Lolium temulentum, a potential model species for cool-season forage grasses, showed a close relation with the major Festuca–Lolium species in the study. Tall wheatgrass was found to be closely related to hexaploid wheat, thereby confirming the known taxonomic relations between these species. While clustering of closely related species was found, the effectiveness of such data in evaluating distantly related species needs further investigations. The phylogenetic trees based on DNA sequences of selected SSR bands were in agreement with the phylogenetic relations based on length polymorphism of SSRs markers. Tall fescue EST-SSR markers depicted phylogenetic relations among a wide range of cool-season forage grass species and thus are an important resource for researchers working with such grass species.Key words: phylogeny, EST-SSR, forage grasses, tall fescue.

scholarly journals Epichloë Endophyte Infection Rates and Alkaloid Content in Commercially Available Grass Seed Mixtures in Europe

2020 ◽  
Vol 8 (4) ◽  
pp. 498
Author(s):  
Jochen Krauss ◽  
Veronika Vikuk ◽  
Carolyn A. Young ◽  
Markus Krischke ◽  
Martin J. Mueller ◽  
...  
Keyword(s):  
Fungal Endophytes ◽  
Grass Species ◽  
Infection Status ◽  
Infection Rates ◽  
Cool Season ◽  
Infected Seed ◽  
Toxic Alkaloids ◽  
Cool Season Grass ◽  
Epichloë Endophyte ◽  
Seed Mixtures

Fungal endophytes of the genus Epichloë live symbiotically in cool season grass species and can produce alkaloids toxic to insects and vertebrates, yet reports of intoxication of grazing animals have been rare in Europe in contrast to overseas. However, due to the beneficial resistance traits observed in Epichloë infected grasses, the inclusion of Epichloë in seed mixtures might become increasingly advantageous. Despite the toxicity of fungal alkaloids, European seed mixtures are rarely tested for Epichloë infection and their infection status is unknown for consumers. In this study, we tested 24 commercially available seed mixtures for their infection rates with Epichloë endophytes and measured the concentrations of the alkaloids ergovaline, lolitrem B, paxilline, and peramine. We detected Epichloë infections in six seed mixtures, and four contained vertebrate and insect toxic alkaloids typical for Epichloë festucae var. lolii infecting Lolium perenne. As Epichloë infected seed mixtures can harm livestock, when infected grasses become dominant in the seeded grasslands, we recommend seed producers to test and communicate Epichloë infection status or avoiding Epichloë infected seed mixtures.

Natural variation and genomic prediction of growth, physiological traits, and nitrogen-use efficiency in perennial ryegrass under low-nitrogen stress

2020 ◽  
Vol 71 (20) ◽  
pp. 6670-6683
Author(s):  
Xiongwei Zhao ◽  
Gang Nie ◽  
Yanyu Yao ◽  
Zhongjie Ji ◽  
Jianhua Gao ◽  
...  
Keyword(s):  
Perennial Ryegrass ◽  
Nitrogen Use Efficiency ◽  
Ridge Regression ◽  
Genomic Prediction ◽  
Prediction Accuracy ◽  
Prediction Models ◽  
Physiological Traits ◽  
Grass Species ◽  
Nitrogen Use ◽  
Use Efficiency

Abstract Genomic prediction of nitrogen-use efficiency (NUE) has not previously been studied in perennial grass species exposed to low-N stress. Here, we conducted a genomic prediction of physiological traits and NUE in 184 global accessions of perennial ryegrass (Lolium perenne) in response to a normal (7.5 mM) and low (0.75 mM) supply of N. After 21 d of treatment under greenhouse conditions, significant variations in plant height increment (ΔHT), leaf fresh weight (LFW), leaf dry weight (LDW), chlorophyll index (Chl), chlorophyll fluorescence, leaf N and carbon (C) contents, C/N ratio, and NUE were observed in accessions , but to a greater extent under low-N stress. Six genomic prediction models were applied to the data, namely the Bayesian method Bayes C, Bayesian LASSO, Bayesian Ridge Regression, Ridge Regression-Best Linear Unbiased Prediction, Reproducing Kernel Hilbert Spaces, and randomForest. These models produced similar prediction accuracy of traits within the normal or low-N treatments, but the accuracy differed between the two treatments. ΔHT, LFW, LDW, and C were predicted slightly better under normal N with a mean Pearson r-value of 0.26, compared with r=0.22 under low N, while the prediction accuracies for Chl, N, C/N, and NUE were significantly improved under low-N stress with a mean r=0.45, compared with r=0.26 under normal N. The population panel contained three population structures, which generally had no effect on prediction accuracy. The moderate prediction accuracies obtained for N, C, and NUE under low-N stress are promising, and suggest a feasible means by which germplasm might be initially assessed for further detailed studies in breeding programs.

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