Identifying a novel superoxide dismutase isoform: a biological marker for evaluating drought-tolerant varieties of rice

摘要

To develop a rapid screening method for drought-tolerant varieties of rice and to establish the relationship between antioxi-dants and drought tolerance, enzyme levels of three antioxidants--superoxide dismutase (SOD), glutathione reductase (GR). andglutathione--were measured in drought-tolerant and drought-sensitive rice varieties, SOD shows at least twofold higher activity in drought-tolerant varieties than in drought-sensitive ones. A similar trend was also observed for glutathione. However, no significant change was observed in GR activity. On native gels, a novel isoform of SOD was observed in drought-tolerant varieties. Polyclonal antibodies were raised against this protein and cross-reaction was observed with a specific protein of drought-tolerant varieties, In addition, amplification of a novel DNA band of 1.4 kb was observed in genomic DNA of drought-tolerant rice varieties using SOD-specific primers. Such a novel polypeptide and/or its corresponding cDNA can be used as a biological marker for rapid screening of drought-tolerant genotypes of rice.