Waterlogging induced oxidative stress and antioxidant activity in pigeonpea genotypes

Abstract

The objective of this study was to examine the role of antioxidant enzymes in waterlogging tolerance of pigeonpea (Cajanus cajan L. Halls) genotypes ICP 301 (tolerant) and Pusa 207 (susceptible). Waterlogging resulted in visible yellowing and senescence of leaves, decrease in leaf area, dry matter, relative water content and chlorophyll content in leaves, and membrane stability index in roots and leaves. The decline in all parameters was greater in Pusa 207 than ICP 301. Oxidative stress in the form of superoxide radical, hydrogen peroxide and thiobarbituric acid reactive substances (TBARS) contents initially decreased, however at 4 and 6 d of waterlogging it increased over control plants, probably due to activation of DPI-sensitive NADPH-oxidase. Antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase and catalase also increased under waterlogging. The comparatively greater antioxidant enzyme activities resulting in less oxidative stress in ICP 301 could be one of the factor determining its higher tolerance to flooding as compared to Pusa 207. This study is the first to conclusively prove that waterlogging induced increase in ROS is via NADPH oxidase.

Expression of antioxidant defense genes in mung bean (Vigna radiata L.) roots under water-logging is associated with hypoxia tolerance

“…RNA blot analysis confirmed that the induction of O 2 regulated genes was related to antioxidative mechanism. Hypoxia induced increase in the transcripts of Cu/Zn-SOD and APX have also been reported in pigeon pea (Kumutha et al 2009;Sairam et al 2009b).…”

“…Further, the rise in ROS from 4th to 8th day of water-logging treatment could be due to the induction of membrane linked NADPH oxidase. Water-logging induced increase in the activity of diphenylene iodonium chloride-sensitive NADPH oxidase dependent superoxide production as well as increase in the expression of NADPH oxidase has been reported in pigeon pea (Kumutha et al 2009 andSairam et al 2009b). Blokhina et al (2001) reported H 2 O 2 formation during anoxia as evidenced by electron dense insoluble precipitate of cerium perhydroxide, visualized through electron microscope.…”

“…Wang and Jiang (2007) reported that SOD and APX were mainly involved in water-logging induced antioxidant responses, and the partial water-logging could also significantly affect root antioxidant activities, particularly in water-loggingsensitive cultivar. Similarly, Kumutha et al (2009) have reported higher activity of SOD, APX, and GR in the water-logging tolerant pigeon pea genotype ICP 301 than susceptible Pusa 207. Increase in the activity of enzymes involved in the ascorbate-glutathione cycle (APX, MDHAR, DHAR, and GR) has also been shown for anaerobically germinated rice seedlings and roots of wheat seedlings (Ushimaru et al 1997, Albrecht andWiedenroth 1994).…”

“…The presence of H 2 O 2 in the apoplast and in association with the plasma membrane has been visualized by transmission electron microscopy under hypoxic conditions in four plant species (Blokhina et al 2001). Recently Kumutha et al (2009) and Sairam et al (2009b) have shown that hypoxia induced ROS in pigeon pea roots are due to induction of membrane linked NADPH oxidase. To control the levels of ROS and to protect cells under stress conditions, plant tissues contain several ROS scavenging enzymes viz., superoxide dismutase (SOD: EC1.15.1.1), ascorbate peroxidase (APX: EC1.11.1.11), glutathione reductase (GR: EC 1.6.4.2), and catalase (CAT: EC 1.11.1.6), and a network of low molecular mass antioxidants (ascorbate, glutathione, phenolic compounds, and a-tocopherol).…”

Effect of Ems on Antioxidant Enzyme Activity and Oxidative Stress of Triticum Aestivum L. Var Hd-2894

“…Higher GR activity was also reported in crop plants like wheat, sorghum, pigeon pea and foxtail millet [14][15][16]17]. The efficiency of antioxidant enzymes determines the amount of dehydration-induced H2O2 in plant cell [18].…”