Transcriptional profiling of heat stress responsive genes in different developmental stages of bread wheat (<i>Triticum aestivum </i> L<i>.</i>)

Abstract

Transcriptional regulation of heat stress response is a complex phenomenon in crop plants, which needs to be evaluated at molecular level for its proper understanding. The present study aimed at identifying differentially expressed heat responsive genes in a thermo-tolerant Indian wheat cultivar Raj3765. Wheat plants of Raj3765 and HD2967 (heat susceptible genotype) were exposed to heat stress at 37°C and 42°C, respectively for different time intervals (30 min to 6 h) at four developmental stages (seedling, tillering, stem elongation &amp; anthesis) and leaf samples collected. Total RNA isolated from leaf samples was used for constructing eight forward subtracted cDNA libraries. A total of 1016 ESTs were generated and assembled into a collection of 377 unigenes, including 114 contigs and 270 singletons. About 23.22 and 20.47% unigenes showed similarities to stress related and abiotic stimulus related genes, respectively; of which 12.59% showed similarities to genes for heat stress responsive functions. Differential expression analysis in response to heat stress of selected six genes by quantitative Real Time-PCR showed up regulation of all the six genes in Raj 3765 as compared to HD2967. The study identified several heat stress responsive genes that can be deployed for development of thermotolerant transgenic wheat.