中国水稻干尖线虫种群致病性分化及其变异的分子机理研究

项目名称： 中国水稻干尖线虫种群致病性分化及其变异的分子机理研究

项目编号： No.30871629

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 谢辉

作者单位： 华南农业大学

项目金额： 30万元

中文摘要： 水稻干尖线虫病是典型的种传水稻病害，近年在中国和世界部分稻区为害加重，并出现新的发病症状，被多国列为检疫性病害。该病害发生情况的变化是否与病原线虫的致病性分化和变异相关，迄今未有研究报道。中国是世界水稻生产大国，稻种出口日益增加，研究中国水稻干尖线虫致病性分化，对该病害的检疫和防控具有重要意义。本项目通过人工接种测试了中国不同地区和寄主的水稻干尖线虫种群致病力，并对致病相关基因和种群遗传多样性进行了研究，取得主要结果如下： (1)明确了中国水稻干尖线虫对水稻的致病力在种群间存在差异，其可能存在致病性分化；(2)首次从水稻干尖线虫分离克隆了3个寄生致病相关基因：甲状腺素运载蛋白基因（Ab-ttl）、脂肪酸结合维生素A蛋白基因（Ab-far）和半胱氨酸蛋白酶基因（Ab-cys），并确定Ab-far和Ab-cys的表达分别定位于线虫真皮层和食道腺，证实主要侵染虫态雌虫和强致病种群的这2个基因表达量明显高于非侵染虫态和弱致病种群；(3)揭示了中国水稻干尖线虫种群至少分属两种不同基因型，具有丰富的遗传多样性。 研究结果为进一步研究和认识水稻干尖线虫流行成灾规律，制定有效防控措施，提供了科学依据。

中文关键词： 水稻干尖线虫；水稻；种群致病性；分化；致病基因

英文摘要： Rice white tip disease,caused by Aphelenchoides besseyi, is an important disease of rice in the world. The rice white nematode, A. besseyi is a quarantine pest in many countries. Recent years, the harm of this disease was increasingly serious in some areas of the world and in China, and there was emergence of a new symptom. There are no reports about the pathogenicity differentiation to rice in various populations of A. besseyi, heretofore. China is one of the major country planting rice in the world, it is important to study the pathogenecity differentiation to rice of A. besseyi. For this project, we tested the pathogenecity to rice of A. besseyi populations from different areas by inoculating in greenhouse, and study its the parasitism and pathogenesis related genes. The main results were as follows: (1) It was demonstrated that various populations of A. besseyi were different in pathogenecity to rice. (2) It was first cloned three pathogenesis related genes form A. besseyi: transthyretin genes (Ab-ttl), fatty acid and retinol-binding protein gene (Ab-far) and cysteine protease gene (Ab-cys). The hypodermis expression of the Ab-far gene and the gland expression of Ab-cys were confirmed by our in-situ hybridization results respectively. Both of expressions of Ab-far and Ab-cys in high-pathogenicity population of A. besseyi were significantly higher than counterpart expressions in low-pathogenicity population of A. besseyi. Amongst expressions of two genes in development stages of A. besseyi, females demonstrated the highest expression. It indicated that the two genes were associated with pathogenicity of the nematode. (3) It was revealed that A. besseyi populations form China had great genetic diversity, and belonged to two gene type. These results provide scientific proof to study the epidemic rule and the effective control measures of A.besseyi.

英文关键词： Aphelenchoides besseyi; rice; population pathogenicity; differentiation; pathogenesis-related genes