Summary
Temperature is one of the most important abiotic factors defining the
yield potential of temperate cereal crops such as barley. The regulators
of heat shock response (HSR); Heat shock factors (HSFs) modulate the
transcription level of heat responsive genes in order to protect the
plants against heat stress. In the present study, a heat shock factor
from wheat (TaHSFA6b ) is overexpressed in barley for providing
thermotolerance. Transgenic barley lines overexpressing TaHSFA6bshowed significant improvement in thermotolerance. The constitutive
overexpression of TaHSFA6b gene upregulated the expression of
major heat shock protein genes as well as other abiotic stress
responsive genes. RNA-seq and qRT-PCR analysis showed upregulation of
HSPs, chaperonins, DNAJ, LEA proteins and genes related to
anti-oxidative enzymes in transgenic lines. Excessive generation and
accumulation of ROS occurred in wild type plants during heat stress;
however, the transgenic lines reflected improved ROS homeostasis
mechanisms in the form of significantly low ROS accumulation under high
temperature. There were no negative phenotypic changes in overexpression
lines. The present study suggests that TaHSFA6b is one of the
major regulators of HSR as it showed the capacity to alter the
expression patterns of main defense related genes and enhance the
thermotolerance of this cereal crops.