中文摘要：

疣粒野生稻高抗水稻白叶枯病，但是其具体的抗性机制目前仍不清楚。一氧化氮（ nitric oxide，NO）是一种重要的信号分子，在植物的抗病反应中起到了重要的作用，然而对于NO是否参与疣粒野生稻对水稻白叶枯病的抗性目前仍缺乏研究。以抗病的疣粒野生稻和感病的水稻品种日本晴为材料，研究了接种白叶枯病菌对叶片病斑、NO含量、NO亚细胞定位和木质部超微结构的影响。结果表明，病菌侵染导致了日本晴叶片呈现枯黄色的干枯斑，疣粒野生稻叶片呈现褐色的凋亡斑，而且野生稻的病斑长度要明显短于日本晴的病斑长度。接种白叶枯病菌后日本晴叶片内NO含量未见明显的变化，而野生稻叶片内NO含量则显著升高，并且大部分的NO定位于导管细胞壁内。进一步通过电镜观察，发现病菌侵染诱导了野生稻叶片导管细胞壁厚度的明显增加。基于这些结果，推测NO参与了疣粒野生稻对白叶枯病的抗性，其功能可能包括诱导导管细胞壁增厚，从而抑制病菌的进一步侵染。

英文摘要：

Or yza meyeriana, a wild rice species , is highly resistant to rice bacterial blight （BB ） , but the resistance mechanism is still unknown.Nitric oxide （ NO） is an important signaling molecule that plays a pivotal role in plant disease resistance responses .However, little study has focused on whether NO is involved in BB resistance of O. meyeriana.In this study, the effects of BB pathogen inoculation on leaf lesion , NO content, NO subcellular location and xylem ultrastructure were studied in O.meyeriana and a susceptible rice cultivar Nipponbare .Pathogen infection caused yellow necrotic lesions in Nipponbare and brown apoptotic lesion in O.meyeriana, and the lesion length was much longer in Nipponbare than in the wild rice .No difference was found in NO content in Nipponbare after pathogen inoculation .However , NO content was prominently increased by pathogen inoculation in the wild rice , and it was further discovered that NO was largely accumulated in xylem cell wall .In addition, electron microscopic observations showed that BB pathogen inoculation induced the thickening of xylem cell wall in O.meyeriana but not in Nippon-bare.Based on these results , we suggested that NO played an important role in the BB resistance of O.me yeriana, and the role might involve the thickening of xylem cell wall that could inhibit further invasion of the pathogen .