Heat shock protein based SNP marker for terminal heat stress in wheat (Triticum aestivum L.)

Abstract

High temperatures during grain filling period of wheat adversely affect the plant growth, yield and grain quality in many regions of world. Tolerance to heat stress is complex phenomenon and controlled by multiple genes imparting a number of physiological and biochemical changes. Attempts were made to identify single nucleotide polymorphism (SNP) and to differentiate the heat tolerant and heat susceptible genotypes of wheat using heat shock protein (HSP16.9) as the target gene. DNA fragment covering a partial sequence of Triticum aestivum L. HSP16.9, were amplified from heat tolerant genotype (K7903) and heat susceptible genotype (RAJ4014), and subsequently analyzed for the presence of SNP. One SNP was found between these genotypes and the analysis of amino acid sequence showed that the base transition (A/G) positioned at 31 amino acid resulted in missense mutation from aspartic acid to aspargine residue. Allele specific primers based on SNP were designed to screen the other heat tolerant and susceptible genotypes. Single-marker analysis explained 29.89% and 24.14% phenotypic variation for grain weight per spike and thousand grain weight respectively. This is the first report of HSP derived SNP marker associated with terminal heat stress in wheat which can be used by the breeders for improving tolerance to high temperatures in wheat breeding programmes.