H_2O_2对水稻白叶枯病菌过氧化氢酶相关基因crg表达的诱导作用

Induction of bacterial catalase-related gene expression by H_2O_2 produced during interaction of rice suspension-cultured cells with Xanthomonas oryzae pv.oryzae or applied exogenously

为了阐明H2O2对水稻白叶枯病菌(Xanthomonas oryzaepv.oryzae,Xoo)过氧化氢酶(CAT)相关基因(crg)表达的诱导作用,本研究定量分析了在水稻细胞-Xoo互作体系及其加入H2O2清除剂CAT后H2O2产量和crg表达;外源添加H2O2后的病菌生长和crg表达。结果表明:在互作条件下,H2O2含量稳定增加,10 h可达到峰值;在互作6 h时crg显著地被诱导表达;加入CAT显著地降低了H2O2含量和crg表达;在外源H2O2胁迫条件下,H2O2以浓度效应的方式影响病菌增殖,显著地诱导了catB和srpA表达。因此,Xoo-水稻互作导致了H2O2的发生。无论是互作产生的还是外源的H2O2均显著地诱导了Xoocrg表达,从而活化了H2O2降解途径。

To elucidate the role of hydrogen peroxide （H2O2 ） produced during the interaction of rice suspen- sion-cultured cells with Xanthomonas oryzae pv. oryzae （Xoo） or applied exogenously in inducing expression of bacterial catalase-related gene （crg）, H2O2 production and crg expression during the rice-Xoo interaction, in which catalase （CAT） was exogenously added or not, were quantitatively analyzed. In vitro growth and crg expression of Xoo exposed to exogenously-applied H2O2 were quantitatively examined as well. Significant increase in H2O2 content and crg expression was observed during the interaction, while reduction in H2O2 concentration and crg expression was obviously found when CAT was exogenously added to the rice-Xoo interacting system. Growth in vitro was inhibited by exogenously-applied H2O2 in a dosage manner, which strongly induced the expression of catB and srpA. Therefore, H2O2 production was resulted from the rice-Xoo interaction, and crg expression was significantly induced by H2O2 either produced during the interaction or added exogenously.