Protection from terminal heat stress: a trade-off between heat-responsive transcription factors (HSFs) and stress-associated genes (SAGs) under changing environment

Terminal heat stress (HS) has adverse effect on the quantity and quality of wheat grains, as evident from the reduction in the yield. Plant has inherited tolerance mechanism to protect itself from the environmental stresses by modulating the expression and activity of stress associated genes (SAGs)/proteins (SAPs) which protect the plant from the damage caused by HS. Heat shock transcription factor (HSF) regulates the expression of SAGs in plant under HS. Bioinformatics and phylogenetic characterization of wheat showed the presence of 56 HSFs classified into three groups—A, B, and C. The regulation of Plant HSFs basically takes place at transcriptional, post-transcriptional, translational, and post-translation levels. It also undergoes post-translational modifications such as phosphorylation, ubiquitination, and Small Ubiquitin-like MOdifier (SUMO)-mediated degradation. The expression of Heat Shock Protein (HSP) genes in response to various stimuli is regulated by HSFs. HSF1 has been reported to be the master regulator for cytoprotective HSPs expression. HSF potentially bind and activate his own promoters as well as the promoters of other members of their gene family. HSFs perceive the elevation in temperature through different signaling molecules like H2O2, kinases and ultimately increase the expression of HSPs and other SAPs inside the cell in order to protect the nascent protein from denaturation. HSFs, being placed at pivotal position, needs to be further identified, characterized and manipulated using the advanced genetic tools in order to regulate the expression of potential genes involved in defense mechanism of plants under stress. It can also be used as potential molecular marker in wheat breeding program.