Differential Activity and Expression Profile of Antioxidant Enzymes and Physiological Changes in Wheat (Triticum aestivum L.) Under Drought

Abstract

Wheat crop may experience water deficit at crucial stages during its life cycle, which induces oxidative stress in the plants. The antioxidant status of the plant plays an important role in providing tolerance against the water stress. The objective of this study was to investigate the impact of water stress on physiological traits, antioxidant activity and transcript profile of antioxidant enzyme related genes in four wheat genotypes (C306, AKAW3717, HD2687, PBW343) at three crucial stages of plants under medium (75% of field capacity) and severe stress (45% of field capacity) in pots. Drought was applied by withholding water for 10 days at a particular growth stage viz. tillering, anthesis and 15 days after anthesis (15DAA). For physiological traits, a highly significant effect of water stress at a particular stage and genotypic variations for resistance to drought tolerance was observed. Under severe water stress, the malondialdehyde (MDA) content increased while the relative water content (RWC) and chlorophyll index decreased significantly in all the genotypes. The drought susceptibility index (DSI) of the genotypes varied from 0.18 to 1.9. The drought treatment at the tillering and anthesis stages was found more sensitive in terms of reduction in thousand grain weight (TGW) and grain yield. Antioxidant enzyme activities [superoxide dismutase (SOD) and peroxidase (POX)] increased with the decrease in osmotic potential in drought tolerant genotypes C306 and AKAW3717. Moreover, the transcript profile of Mn-SOD upregulated significantly and was consistent with the trend of the variation in SOD activity, which suggests that Mn-SOD might play an important role in drought tolerance.

Induction of antioxidant system in niger (Guizotia abyssinica Cass.) under drought stress

“…Guaiacol specific POXs are known to play a vital role in various biosynthetic processes like ethylene and auxin metabolism, maintain redox homeostasis in plasma membrane, lignification and suberization of cell wall and several other developmental and defense mechanisms (Lepeduš et al, 2004) thereby, making it an indispensable component of the antioxidant system. Elevated levels of GPOX up to 48 h of applied stress, and its decline beyond 48 h suggested the enzymes potential ROS quenching during 48 h of drought stress, and its insufficiency beyond 48 h of drought (Figure 1), similar to observations made in wheat species under drought stress (Sheoran et al, 2015).…”

Content of Selected Vitamins and Antioxidants in Colored and Nonpigmented Varieties of Quinoa, Barley, and Wheat Grains

“…In wheat, BH, BD, and S varieties exhibited significantly greater SOD activity compared to the colored K variety. The SOD content can be increased by severe water stress; it might play an important role in drought tolerance (Sheoran et al., ).…”

Physiological and Biochemical Responses of four cassava cultivars to drought stress

“…Drought stress can trigger a series of plant regulation, not only including the physiological and biochemical response but also containing the regulation of gene expression 16 . Studying the relationship between gene expression and stress tolerance can provide reliable information on understanding antioxidant gene activation 44 .…”

“…Currently, it is prevalent to study the mechanism of stress response at genetic, physiological and molecular levels 15 . To have a better understanding of the factors affecting antioxidant regulation, it is important to associate antioxidant enzyme activity and related-gene expression in different genotype species 16 . However, the studies on response mechanism under drought stress in cassava were limited to the physiological or molecular method only.…”