Functional analysis of Candidate Genes Associated with Stay Green Trait in Wheat

摘要

The delayed senescence (stay green) has been frequentlyattributed to significant yield gains in different crops includingwheat. This study aims to check the expression profiling oforthologous stay green genes reported from rice, sorghum in wheatgenotypes. A total of 100 wheat genotypes were evaluated and fournew lines with stay green phenotype were identified through fieldscreening and chlorophyll content analysis. All the data recordingand chlorophyll content estimation was done in four growth stages(GS69, GS73, GS77 and GS83). The chlorophyll content in staygreen and non-stay green genotypes was similar during initial stagesof growth. During later stages, the chlorophyll content in stay greenwas clearly higher than that of non-stay green genotypes. Over 167primers were designed from known sequences of other crops andscreened for amplification and polymorphism. Five of these primersproduced clear profile with single band. These primers were used forQRT PCR using six lines including five stay green and one non-staygreen line. Three of these primers 4540 F1R2, 4540 F, 5563 Fshowed differential expression between stay green and non-staygreen genotypes. The expression was more in stay green genotypesthan in non-stay green genotypes. All the three primers wereoriginally designed from different regions of the same gene sequencefrom Oryza sativa var. japonica NYC3 mRNA. These resultsindicating that this region (sequence) of the genome may be highlycorrelated with stay green trait in wheat. While other two primerscould not show differential expression within the contrastinggenotypes. There expression was low and found almost consistent inall growth stages. The results are quit expected becauseinsertion/deletion within the gene is very rare most of the distinctphenotypes arise due to singe base substitution so the quantitateestimation of gene expression is prerequisite. Further investigationon expression and regulation of this gene may provide information onthe mechanism of this trait and its potential relationship with droughttolerance in wheat.