ABSTRACT

Plants being sessile are continuously exposed to environmental stresses such as drought, salinity, cold, and hot temperatures which present major challenges in achieving sustainable food production. Plants are unable to express their full genetic potential for production in stressful environments (Zeigler, 1990; Gao et al., 2007; Blum, 2017). When subjected to stresses, a complex reaction is triggered in plants involving a wide variety of physiological and biochemical responses to overcome, avoid, or nullify the effects of stresses. Tolerance or sensitivity of plants toward a particular stressful condition depends on the genetic and biochemical make-up of the species. During environmental stresses, plants recognize the stress stimulus via various sensors which in turn activate a signal transduction cascade. Plant hormones, signal transducers, secondary messengers, and transcription regulators relay the signal, activating stress-responsive genes (Zhu, 2001; Kaur and Gupta, 2005; Sharma and Dubey, 2007; Kumar et al., 2008; Guo et al., 2009; Gupta et al., 2009; Cvikrová et al., 2013; Danquah et al., 2014; Gilroy et al., 2018). Several signals thus converge to regulate stress-inducible genes that encode proteins and enzymes. The expression of these genes causes the accumulation or depletion of certain metabolites, alteration in the activity behaviors of many enzymes, overall changes in protein synthesis, and, of particular interest, synthesis of novel proteins specific to particular stress, which directly participate in stress metabolism and contribute to the specificity of the adaptive response under stress (Guo et al., 2009; Casaretto et al., 2016).