拟南芥属姐妹种间的生殖隔离及其分子机制与进化

生殖隔离是物种形成、维持种间生物多样,进而影响生态系统功能的基础。生殖隔离的分子机制及其进化一直是生命科学和生态学的核心问题和进化生态学研究的前沿领域。单向不亲和（UI）是广泛存在于植物姐妹种间的一种独特的合子前生殖隔离现象，虽然与种内的自交不亲和（SI）反应在柱头和花粉的识别和排斥上的细胞学表现类似，但是关于UI反应的分子机制及其进化的研究则刚刚起步。经过10多年对拟南芥及其姐妹种交配系统演化的研究，我们发现了拟南芥及其姐妹种间的UI现象，突破了种间杂交获得可育后代及区分UI和SI反应等瓶颈，在拟南芥与A.lyrata 、A.arenosa和 A. hellari中建立了一个可用数量性状图位克隆来阐明UI决定基因及其进化的模式系统。本项目将深入揭示UI的分子机制及其进化机理，我们的研究不仅对物种起源及种间生物多样性维持机制,而且对克服作物远缘杂交时的杂交不亲和现象都将产生重要影响。

Reproductive isolation is critical for speciation and maintaining biodiversity and ecosystem functions. The molecular mechanism and evolution of reproductive isolation has long been the spotlight in life sciences and Ecology and is becoming the new frontier in Evolutionary Ecology. Unilateral incompatibility (UI) is a unique mechanism to restrict gene flow among discrete populations in flowering plants, leading to prezygotic reproductive isolation among closely related species. Although similar cellular manifestations in incompatible interactions have been observed between UI and Self-incompatibility (SI) responses, the molecular mechanism and evolution of UI is just emerging. We found UI among Arabidopsis thaliana and its closely related species A. lyrata, A. arenosa and A. hellari. After 10 year intensive investigations on the evolution of mating system in the genus Arabidopsis, we obtained fertile progenies of inter-species hybrids and identified different S haplotypes to be used in generating populations to analyze QTLs underlying UI in both stigma and pollen sides. Our results show that a few major QTLs underly UI responses in both female and male sides. Backcrossing was used to generate populations for QTL analysis and will be further used to generate near-isogenic lines (NILs) for fine-mapping the major QTLs and to identify the underlying genes. Our findings will provide new insights into the molecular mechanism and evolution of reproductive isolation in closely-related plant species as well as speciation, and will also provide new avenues to circumvent the hybrid-incompatibility when inter-species crossings are utilized in crop breeding to pyramid elite traits from closely related species .