"Review of literaturerole of LEA during water stress (Garay-Arroyo et al., 2000). Dehydrins act aschaperones and help in stabilizing the structure of vesicles, proteins and membranestructures of plants under water stress conditions (Close 1997).myo-inositol 1-phosphate synthase (MIPS) Inositol is a six-carbon cyclo-hexane hexitol found ubiquitously. Inositol isessential for plant growth and development. It involves in various physiological andbiochemical processes such as growth regulation, cell membrane biogenesis, hormonalregulation and also utilized in abiotic stress-induced raffinose and galactinol synthesis(Loewus and Murthy 2000; Taji et al., 2002). MIPS gene regulation under abiotic stressconditions was previously reported (Kaur et al., 2008). Increased accumulation ofinositol by the transcriptional induction of the MIPS gene was reported inMesembryanthemum crystallinum by Ishitani et al., (1996) under abiotic stressconditions. Boominathan et al., (2004) has reported the accumulation of MIPS in Cicerarietinum under dehydration stress. The transgenic Arabidopsis plants expressingCaMIPS2 from chickpea has shown more tolerance to drought over control (Kaur et al.,2013).Proteins involved in detoxification- - - - -ROS like O , H O , HO , OH , ROOH, ROO , and RO are produced during2 2 2 2 severe stress conditions. Subcellular compartments like chloroplasts, peroxisomes andmitochondria generate O ¯ and H O , during electron transport and enzymatic reactions2 2 2 (Del Rio et al., 2002). An increased ROS accumulation, lipid peroxidation, and proteinmodification have been observed in a number of plants species under water deficitconditions (Esfandiari et al., 2008).Lipid peroxidation takes place when ROS levels have reached the threshold,directly affecting normal cellular functioning and also aggravating the oxidative stress16 Review of literaturethrough the production of lipid-derived radicals (Montillet et al., 2005). ROS-mediatedmembrane damage is the major cause of the cellular toxicity of water stress (Turkan etal., 2005) and salinity (Sudhakar et al., 2001). Membrane damage is taken as aparameter to determine the lipid destruction of the membrane under various stressconditions. Lipids peroxidation is considered as the most damaging process known tooccur in every living organism. During lipid peroxidation, small hydrocarbon fragmentsMDA will be formed from polyunsaturated precursors (Garg and Manchanda, 2009). Despite the destructive role in cells, ROS can act as signaling molecules inbiological processes (Mittler, 2011). Thus, plants adjust ROS concentrations betweencertain thresholds by means of production and scavenging mechanisms (Khosravinejadet al., 2008; Sekmen et al., 2014). A variety of scavengers, such as superoxidedismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione peroxidase(GPX), glutathione-S-transferase (GST) (Mittler et al., 2004) is produced during stressto reduce the adverse effect of ROS on plants. Gomez et al., (2004) and Smirnoff(2005) has demonstrated the role of antioxidative isozymes in protection againstoxidative stress in various transgenic plants. Production and scavenging of ROS wereshown in figure 2. SODThe first line of defense against the toxic effects of elevated levels of ROS is theproduction of SOD. The upregulation of SOD is implicated in combating oxidativestress caused by abiotic and biotic stresses, have a critical role in the survival of plants.- SOD shows dismutase activity which removes O by catalyzing its dismutation; one2 - O being reduced to H O and other oxidized to O (Del Rio et al., 2002). Increased2 2 2 2 activity of SOD was observed under water stress in wheat, cowpea, mungbean, andCatharanthus roseus (Manivannan et al., 2007; Dutta and Bera, 2007; Jaleel et al.,17 Review of literature2007). Overexpression of SOD genes in transgenic plants has shown less oxidativedamage under stress conditions. Transgenic wheat plants overexpressing MnSOD genehas shown less oxidative damage with a significant increase in SOD and GR activitiesunder photo-oxidative stress was reported by Melchiorre et al., (2009). Overexpressionof a MnSOD in transgenic Arabidopsis plants has also shown increased tolerancetowards salt stress (Wang et al., 2004). In another study overexpression of SOD genessuch as CuSOD or ZnSOD in transgenic tobacco plants has shown enhanced waterstress and salt stress tolerance over control plants (Badawi et al., 2004).APXAPX play a crucial role in the detoxification and scavenging of cellular H O 2 2,the toxic product of superoxide dismutation under normal and stress conditions (Asada,1999).APX converts H O into water-water and ASH-GSH cycles and utilizes ASH as2 2an electron donor. The APX family consists of different isoforms including chloroplastthylakoid (tAPX) as well as stromal soluble form (sAPX), and glyoxisome membraneforms (gmAPX) and cytosolic form (cAPX) (Noctor et al., 1998). Increased peroxidaseactivity and its role in abiotic stress tolerance were shown in various plants (Jaleel etal., 2008). Overexpression of APX in chloroplasts of Nicotiana tabacum has shownenhanced tolerance to salt and water stress (Badawi et al., 2004). Significant increase inthe APX content was reported in transgenic groundnut plants overexpressing MuNAC4gene after drought stress imposition (Pandurangaiah et al., 2014). Antioxidant genesuch as OsAPXa or OsAPXb was derived from rice plant by Lu et al., (2007).Overexpression of these genes in transgenic Arabidopsis plants exhibited increasedtolerance to salt stress. 18 "