DEFENCE GENES AND ANTIOXIDANT ENZYMES IN STAGE-DEPENDENT RESISTANCE TO RICE NECK BLAST

The rice variety Jiajing3768 is susceptible to neck blast at the booting stage (BS) but resistant at the full heading stage (FHS). This variety was used to analyze the inducible expression of defence genes and activities of antioxidant enzymes in the necks, at both the BS and FHS, after inoculation with Magnaporthe oryzae. We found that defence genes PRlb (pathogenesis-related class Ib), PBZ1 (probenazole-inducible gene), PAL (phenylalanine ammonia-lyase), and CHS (chalcone synthase) may play roles in the resistance difference to neck blast between the BS and FHS in Jiajing3768. No significant differences were observed between the BS and FHS in the inducible expression of PRla, PR4, and JIOsPR10 (jasmonic acid induced PR 10). The antioxidant enzymes Superoxide dismutase, peroxidase, catalase, glutathione reductase, and malondialdehyde coordinately participated in the stage-dependent resistance difference in Jiajing3768, and that oxidative damage is lower in the necks at the FHS than at the BS.