元阳梯田传统水稻品种具有低稻瘟病发病率的特点，而外来引进品种稻瘟病发病率较高。UV-B辐射对室内水稻稻瘟病有显著影响，但大田条件下UV-B辐射对水稻稻瘟病的影响与机理的认识有限。项目以元阳梯田传统水稻品种白脚老粳为研究对象，模拟不同强度UV-B辐射增强，开展连续4年的大田试验，观测大田水稻稻瘟病的病情指数，稻瘟病菌的生长与产孢，水稻叶片的形态结构、抗病物质含量、防御酶活性及其编码基因表达等指标，分析UV-B辐射对大田稻瘟病发生、病菌侵染力、水稻叶片抗病形态结构、生理与分子的影响，研究元阳梯田水稻-稻瘟病菌互作对UV-B辐射响应的生理与分子特征，及其与稻瘟病发生的关系，探讨UV-B辐射影响元阳梯田水稻-稻瘟病菌互作的机理。为地表UV-B辐射增强情景下大田作物病害发生发展的规律与变化趋势提供新的认识，丰富UV-B辐射与作物病害发生相互关系的理论，具有重要的意义。

Yuanyang Terrace is a typical and representative paddy ecosystem with sustainability, in which the local traditional rice varieties have the characteristics of low incidence of rice blast. Some significant effects of UV-B radiation on the rice blast were observed under laboratory conditions. However, the effects and mechanisms of UV-B radiation on the rice blast under field conditions were poorly understand. In this project, some field experiments for 4 consecutive years were carried out to investigate the effects of enhanced UV-B radiation on a traditional rice variety Baijiaolaojing in Yuanyang Terrace. In these experiments, some indexes will be observed that including the index of rice blast, the growth and sporulation of Magnaporthe grisea, the morphology of rice leaves, the contents of disease-resistant material, the activity of defensive enzymes and the expression of coding gene. The aims included: (1) to discover the effects of UV-B radiation on the incidence of rice blast, the infection level of Magnaporthe grisea, the leaves morphology, physiology and molecular indicators related to disease resistance; (2) to understand the physiological and molecular characteristics of the interactions between rice and Magnaporthe grisea to UV-B radiation and the relationship with incidence of rice blast; (3) to explore the mechanisms in the effects of UV-B radiation on the interactions between rice and Magnaporthe grisea. This project would provide new knowledge about the change trends of the crops diseases to enhanced UV-B radiation in field conditions, and enrich the theory on the relationship between UV-B radiation and crop diseases.