Physiological and cytological mechanisms of silicon-induced resistance in rice against blast disease
Physiological and cytological mechanisms of silicon-induced resistance in rice against blast disease
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DOI：
10.1111/j.1399-3054.2008.01140.x
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发表时间：
2008-10-01
影响因子：
6.4
通讯作者：
Zhu, Xiaoyuan
中科院分区：
文献类型：
--
作者：
Cai, Kunzheng;Gao, Dan;Zhu, Xiaoyuan
水稻（Oryza sativa L.）稻瘟病是由稻瘟病菌（Magnaporthe grisea）引起的一种水稻病害，是世界上水稻种植区最具破坏性的病害之一。硅是一种重要的营养元素，尤其是对水稻而言。以两个抗稻瘟病性不同的水稻近等基因系CO 39（感病）和C101 LAC（Pi-1）（抗病）为材料，研究了施硅对稻瘟病发病率和严重程度的影响。本文对硅素诱导水稻抗病性的生理和细胞学机制进行了研究。外源硅的应用在2毫米的浓度降低了45%的CO 39和56%的C101 LAC（Pi-1）的疾病指数。单独施硅不会改变两个等基因系水稻叶片中木质素含量以及过氧化物酶（POD）、多酚氧化酶（PPO）和苯丙氨酸解氨酶（PAL）等防御相关酶的活性。但接种M.硅处理显著提高了两个同基因系叶片中POD、PPO和PAL的活性。Si处理的接种苗中Si和木质素含量也显著增加。环境扫描电镜观察结果表明，施硅使水稻叶片哑铃体上硅存款增多，气孔保卫细胞上硅乳突增多。这些结果表明，硅诱导水稻叶片的防御反应和细胞硅化共同参与了硅诱导水稻对稻瘟病的抗性。
Rice (Oryza sativa L.) blast disease caused by Magnaporthe grisea is one of the most destructive diseases in the rice-growing areas of the world. Silicon is an important nutritional element especially for rice. Two near-isogenic lines of rice with different resistance to blast disease, i.e. CO39 (susceptible) and C101LAC (Pi-1) (resistant), were selected to determine the effects of Si amendment on the severity and incidence of rice blast disease. The physiological and cytological mechanisms involved in the induced disease resistance by silicon were investigated. Exogenous Si application at a concentration of 2 mM reduced the disease index by 45% for CO39 and 56% for C101LAC (Pi-1). Si application alone did not change lignin content and the activities of defense-related enzymes including peroxidase (POD), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) in rice leaves of both isogenic lines. However, after inoculation with M. grisea, Si-treated rice plants significantly increased the activities of POD, PPO and PAL in leaves of both isogenic lines. Si and lignin content were also significantly increased in Si-treated inoculated seedlings. Environmental scanning electron microscope observations revealed that Si amendment resulted in higher Si deposit on dumbbell bodies in the rice leaves and silicon papilla accumulation on the guard cell of stoma. These results suggest that silicon-induced defense response and cell silicification of rice leaves altogether contribute to the silicon-induced rice resistance to blast disease.