落粒基因序列和微卫星指纹揭示的杂草稻起源及分子进化

杂草稻是全球最严重稻田恶性杂草之一，严重影响了水稻可持续生产。揭示杂草稻危害的生物学机制并对其有效防治非常必要。杂草稻成功入侵和危害的重要原因是其具有丰富的遗传多样性，而多样性的形成和维持与杂草稻起源和进化密切相关。本项目通过前期研究，将杂草稻复杂起源方式归纳为与野生稻相关的"野生起源"和仅与栽培稻相关的"作物起源"，锁定上述关键科学问题，利用编码落粒性状基因sh4和qsh1 DNA序列以及微卫星分子指纹多态性，开展如下研究：1）比较广泛来源杂草稻、野生稻和栽培稻sh4和qsh1及旁侧序列的多态性，揭示杂草稻起源方式；2）利用微卫星分子指纹分析杂草稻与野生稻、栽培稻的遗传结构和微进化关系；3）综合DNA序列和微卫星指纹多态性结果，确定杂草稻的起源方式及分子进化过程。上述研究将揭示杂草稻遗传多样性形成和维持机制，为阐明杂草稻危害规律及制定有效控制策略提供科学依据。

Weedy rice is one of the most noxious weeds in rice fields and has severely affected sustainable rice production. The effective control of weedy rice is important for rice production. The abundant genetic diversity of weedy rice promotes its successful invasion to a rice field, causing significant yield losses of cultivated rice. The formation and maintenance of such diversity are intimately associated with the origin and evolution of weedy rice. Our previous research indicated that the complicated pathway of weedy rice origin can be divided as: the "wild origin" that involves wild rice species; and the "cultivar origin" that only involves cultivated rice. The project will focus on the DNA sequence polymorphisms of the genes encoding seed shattering traits (Sh4 and qsh1), as well as microsatellite polymorphisms to conduct the following researches: 1) to compare the sequence polymorphisms of the Sh4 and qsh1 genes and their flanking regions in a large sample set including weedy rice, wild rice and cultivated rice from wide sources to reveal the origin of weedy rice; 2) to determine genetic structure and affinity of weedy rice in comparison with wild rice and cultivated rice based on microsatellite fingerprints; and 3) to determine the origin and evolutionary process of weedy rice based on the DNA sequence and microsatellite data. The resolution of the origin and genetic diversity in weedy rice will provide a strong scientific basis for understanding the reason of weedy rice persistence in rice fields, which causes serious losses of rice grain yield, and consequently design a method for effective weedy rice control.