Abstract
We obtained the transgenic rice plants overexpressing the OsHCTR (NADPH-dependent HC-toxin reductase) gene. Previously, we reported that these plants showed tolerance to the biotic and the abiotic stresses. Last year, we reported that the overexpressing this gene resulted in the increase of NAD(P)(H) level and the activation of NAD synthetase. Here, we analyzed the maize plants possessing mutated Hm1 gene (homologue of OsHCTR gene). The result that the Hm1 mutation (hm1 / hm1) was also associated with loss of stress tolerance due to lowered level of NAD. Metabolites analysis also showed that aspartic acid level was increased, suggesting that amino acid may be a precursor for NAD. Based on this result, Both Hm1 and OsHCTR gene are functionally important to sustain stress tolerance in higher plants.
