Chapter 15 - Plant transcriptional regulation in modulating cross-tolerance to stress

Abstract

Plants are exposed to a broad range of biotic and abiotic stresses during their growth and development. These stresses, either individually or concurrently, have drastic effects on the life cycle of the plants, especially reproductive phase and grain/pod filling phase. Plants generally employ gene regulatory signaling networks involving phytohormones, transcriptional factors (TFs), and reactive oxygen species (ROS), and trigger the expression of stress-associated genes (SAGs) to cope with the adverse effects of such stresses. In this signal transduction process, TFs play a pivotal role in signal perception and SAG expression. TFs could be activators/repressors in transcriptional regulation of SAGs. A large number of TFs has been identified and broadly classified based on the presence of DNA binding domain into different families. Their specific functions have been established against different biotic and abiotic stresses. Recent studies have unearthed that a combination of stresses instigate unique molecular responses, which are distinct from those responsive to individual stresses. Also, biotic and abiotic stresses share common signaling pathways, responses, and triggering of defense networks, leading to cross-tolerance. As signaling cascade plays a very important role in cross-tolerance phenomena, microRNAs (miRNAs), which also effect transcriptional regulation of gene expression by epigenetic modifications, require a special mention. Elucidation of mechanisms underlying transcriptional control of stress-responsiveness in plants is imperative. In this chapter, the complex network of transcriptional regulation with special reference to its effect on cross-tolerance to different stresses will be discussed. The invaluable insights into mechanisms underlying growth and differentiation of plants under adverse conditions will provide ways and means to obtain a better crop phenotype.