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

• Published in: Acta physiologiae plantarum Vol. 33; no. 3; pp. 735 - 744
• Main Authors: Sairam, Raj K., Dharmar, Kumutha, Lekshmy, S., Chinnusamy, Viswanathan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.05.2011
• Subjects: Agriculture; Biomedical and Life Sciences; Life Sciences; Original Paper; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Reactive oxygen species; Anoxia; Glutathione reductase; Hypoxia; Superoxide dismutase; Superoxide radical; Ascorbate peroxidase; Gene expression; Mung bean; Water-logging
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-010-0598-3

This study was conducted to examine the extent of oxidative stress and the role of antioxidant enzymes on hypoxia tolerance in highly tolerant wild species Vigna luteola , and mung bean ( Vigna radiata ) cvs. T 44 (tolerant) and Pusa Baisakhi (susceptible). Two days of water-logging caused about 40–50% decline in superoxide radical (O 2 ·− ) and hydrogen peroxide (H 2 O 2 ) contents in all the genotypes, however, further water-logging to 8 days caused significant increase in O 2 ·− and H 2 O 2 contents, and the values were 80–90% of the control values. In control and revived plants O 2 ·− and H 2 O 2 contents were higher in Pusa Baisakhi, while under water-logging stress T 44 and V. luteola showed greater increases in the O 2 ·− and H 2 O 2 contents. Hypoxia induced increase in superoxide dismutase, ascorbate peroxidase, and glutathione reductase activities were higher in T 44 and V. luteola compared with Pusa Baisakhi; and the increases in T 44 and V. luteola continued up to 8th day of water-logging, while in case of Pusa Baisakhi, the maximum increase was observed only on the 2nd day of water-logging. Gene expression studies showed enhanced expression of cytosolic-Cu/Zn-superoxide dismutase (SOD) and cytosolic-ascorbate peroxidase (APX) in the roots of waterlogged V. luteola and T 44, while little expression was observed in control or treated plants of Pusa Baisakhi. PCR band products were cloned and sequenced, and partial cDNAs of Cu/Zn - SOD and APX , respectively, were obtained. Results suggest that increase in the activity of antioxidant enzymes is to scavenge reactive oxygen species produced both during and after relief from water-logging stress.