Contribution of Antioxidative Enzymes and Anoxia Responsive Genes to Submergence Tolerance in Rice: A Review

Flooding/submergence of rice fields is a severe problem in South and South-East Asia,affecting more than 20 million hectares of rice every year.Submergence creates hypoxic or anoxic condition causing poor germination,seedling establishment,and enormous yield loss.Standing water in the field from weeks to months also leads to significant yield losses when large part of aerial tissues is under water.For flash flooding,a rice variety FR1A3 with tolerant gene (SUB1A) was identified.SNORKEL1 and SNORKEL2 have been identified for their ability to survive deep-water flooding by rapid elongation.Submergence stress has also been reported to adversely affect cell division and damage cellular and organelle membranes.Research on antioxidative enzymes response and genes that confer tolerance to prolonged flooding is in progress.Here we review the different anoxia responsive genes and the potential involvement of antioxidative enzymes,such as superoxide dismutase,catalase,ascorbate peroxidase and glutathione reductase,which occur in cells of rice plant exposed to submergence stress.