Abstract: The harpin-encoding gene (hrf1),derived from Xanthomonas oryzae pv. oryzae,was transferred into a rice variety R109. Expressing hrf1 in rice enhanced the resistance to ZC3,ZD1 and ZG1 races of M. grisea,and only a few lesions developed on leaves of transgenic plants infested with ZB13 races,showing that the expression of hrf1 confers nonspecific resistance in rice to M. grisea. Transgenic plants and their T1,T3,T5 and T7 progenies were highly resistant to major M. grisea groups in rice-growing areas. The expression of several key plant defense genes (OsPR1a,OsPR1b,PAL,and Chia4a) and signal transduction gene NPR1 (non-expressor of PR genes) were enhanced in transgenic lines which were resistant to rice blast. Silicon content,which often correlates with resistance to M. grisea,was increased in transgenic lines. The results indicated that expressing harpin-encoding gene in rice exhibited stable nonspecific resistance,suggesting that the expression of harpin-encoding genes may provide effective controls on rice blast and offer new hope for generating broad spectrum resistance in other crops.

Key words: transgenic rice, harpin-encoding gene, rice blast, nonspecific resistance, mechanism of resistance

摘要： 以表达水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae）编码harpin广谱抗性激发子的hrf1基因的转基因系为材料，在温室和田间病圃鉴定它们对稻瘟病菌的抗性，分析转基因水稻抗稻瘟病的作用机制。研究结果显示，转hrf1基因水稻对稻瘟病菌ZC3、ZD1和ZG1小种表现高抗，对ZB13表现中抗，表明hrf1基因在水稻中表达可以产生非小种专化抗性。在稻瘟病圃中对水稻稻瘟病抗性鉴定结果显示，转hrf1基因水稻在T1、T3、T5和T7代对稻瘟病菌都表现很好的抗性，表明转hrf1基因水稻对稻瘟病菌的抗性能稳定遗传。 转hrf1基因抗病水稻中防卫反应基因OsPR1a、OsPR1b、PAL和Chia4a以及正向调控水杨酸介导信号传导的NPR1基因的表达显著增强。转基因抗病水稻中硅含量显著提高。Harpin编码基因在水稻中表达，可能通过激发水稻中防卫反应基因的表达，提高水稻中硅含量等，从而使水稻产生对稻瘟病菌的广谱抗性。

关键词: 转基因水稻, harpin编码基因, 稻瘟病, 非专化抗性