Natural variations at the Stay-Green gene promoter control lifespan and yield in rice cultivars

Jiang

et al. 2020

BMC Plant Biol

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.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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

Jiang

et al. 2020

BMC Plant Biol

“…One recent report by Shin et al (2020) showed that the natural variation within the promoter region of a Chl catabolic gene, OsSGR, was a predominant genetic factor for delayed leaf senescence in rice, and introgression of the promoter region of OsSGR from Japonica-type rice to Indica-type rice lead to delayed leaf senescence rate and up to 12.7% increased grain yield in the Indica-type rice [31]. The study by Shen et al (2020) showed the potential of making use of the natural variation of CCGs [31]. Findings in this study showed that there are rich natural variations of these CCGs in terms of their responses to heat tolerance, and CCGs could also be used as potential target genes and/or markers for genetic improvement of ryegrass through gene editing or maker-assisted breeding.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

Preprint

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.

“…One recent report by Shin et al (2020) showed that the natural variation within the promoter region of a Chl catabolic gene, OsSGR, was a predominant genetic factor for delayed leaf senescence in rice, and introgression the promoter region of OsSGR from Japonica-type rice to Indica-type rice lead to delayed leaf senescence rate and up to 12.7% increased grain yield in the Indica-type rice [31]. The study by Shen et al (2020) showed the potential of making use of the natural variation of CCGs [31]. Findings in this study showed that there are rich natural variations of these CCGs in terms of their responses to heat tolerance, and CCGs could also be used as potential target genes and/or markers for genetic improvement of ryegrass through gene editing or maker-assisted breeding.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

Preprint

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.