Characterization of rice G protein gamma Type A Subunit and its functional validation in salinity stress tolerance in rice

Abstract

Environmental factors are the primary cause of crop failure, causing average yield losses of newlinemore than 60% for major crops worldwide (Bray et al. 2000). The abiotic stresses that plants newlineencounter most frequently and that adversely affect growth are drought, salinity, flooding, newlineand low or high temperature. Plants are sessile by nature and have evolved sophisticated newlinemechanisms to adapt to environmental changes and challenges. Environmental clues trigger newlinephysiological and molecular responses enabling the plant to prevent or minimize exposure to newlinestressful conditions, or to acclimate and overcome the unavoidable hurdles (Bartels et al. newline2005). newlineSoil salinization is a growing problem for agriculture worldwide. Salt accumulation in newlinearable soils is mainly derived from irrigation water that contains trace amounts of sodium newlinechloride (NaCl) and from seawater (Flowers and Yeo 1995; Tester and Davenport, 2003). newlineIncreased soil salt concentrations decrease the ability of a plant to take up water and, once newlineNa+ and Cl- are taken up in large amounts by roots, both Na+ and Cl- negatively affect growth newlineby impairing metabolic processes and decreasing photosynthetic efficiency (Flowers and Yeo newline1995; Maser et al. 2002). Thus, plant salt stress can be subdivided into early-occurring newlineosmotic stress and accumulating ionic Na+ stress (Sahi et al. 2006; Munns and Tester, 2008). newlinePlants enact mechanisms to mitigate osmotic stress by reducing water loss while maximizing newlinewater uptake. Furthermore, plants minimize the harmful effects of ionic Na+ stress by newlineexclusion of Na+ from leaf tissues and by compartmentalization of Na+, mainly into vacuoles newline(Munns and Tester, 2008). The mechanism underlying the environmental stress response in newlineplants is probably more advanced and prominent than in animals however salt stress newlinedecreases crop yields and is leading to continuing loss of arable land. Such losses are newlinecompounded by the additional challenge that agriculture needs to provide enough nutrition newlinefor a world population that is rapi