Analysis of Antioxidant Characteristics and Related Gene ExpressionProfiles of Rice Drought-Tolerance Lines Derived from Embryo-Soakingwith Alternanthera philoxeroides DNA Solution

Abstract

International audienceDrought is one of major abiotic stress limiting rice stable production. In thestudy, four rice cultivars, IAPAR9 (upland rice cultivar), H8 and H10 (drought-tolerance variant lines derived from 6527 embryo-soaked with Alternantheraphiloxeroides DNA solution) and 6527 (ordinary rice cultivar), were used tostudy the antioxidant characteristics of drought-resistant varieties by superoxidedismutase (SOD) activity, peroxidase (POD) activity, malondialdehyde (MDA)content and their related gene expression profiles. The results showed that theSOD activity, POD activity and MDA content were increased significantly underdrought stress, while decreased in the yield and its related traits such as seedsetting ratio, 1000-grain weight and grain number per panicle. The SOD andPOD activities in drought-tolerant rice (H8, H10 and IAPAR9) were significantlyhigher than those in drought-sensitive 6527. Less MDA content was producedin drought-tolerant rice (H8, H10 and IAPAR9) than sensitive 6527. The yieldof H8 was significantly higher than that of other cultivars, and the seed settingratio and 1000-grain weight from those with drought-tolerant were significantlyhigher than that of sensitive 6527. After drought stress, there were 11 genesrelated to antioxidant progress whose expression profiles changed significantlybetween H8 and 6527. These results suggested that drought tolerant cultivarsmaybe subdue harms from the peroxidation by inducing the express of relatedgenes of antioxidant process, further increasing the SOD activity and PODactivity. Thus, their enhancement of drought resistance could maintain thenormal growth and development under drought stress and achieve maximumphotosynthate storag