Natural Variation in Expression of Self-Incompatibility in A. Thaliana: Evolution of Inbreeding

拟南芥自交不亲和性表达的自然变异：近交进化

• 批准号: 0414521
• 负责人: Mikhail Nasrallah
• 金额: --
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0414521&HistoricalAwards=false
• 关键词: Natural; Variation; Expression; Self; Incompatibility; Natural; Variation; Expression; Self; Incompatibility

The switch from out-crossing to self-fertilizing (inbreeding) mating system is one of the most prevalent evolutionary trends in plant reproduction. A major goal of the proposed study is to identify and characterize the genes underlying evolutionary switches to self-fertility, and thus understand a major process in the reproductive isolation of plant species. In crucifers, two genes, which encode the S-locus receptor kinase SRK and its ligand the S-locus cysteine-rich peptide SCR, functiontogether to prevent self-pollination and are thus responsible for the self-incompatible (out-crossing) mode of mating. The model plant Arabidopsis thaliana is a highly self-fertile species, but it can be rendered self-incompatible by transfer of these two genes from its self-incompatible relative A. lyrata. Natural populations of A. thaliana were found to exhibit polymorphisms in their SRK/SCR sequences, and to harbor hidden variation for expression of self-incompatibility, which can only be uncovered by transfer of A. lyrata SRK and SCR genes. Genetic and molecular analysis of this variability will allow, for the first time, a study of the genetics of inbreeding in natural populations of a genetically tractable species. The study is expected to provide insight into the changes in mating system that occur during or subsequent to speciation, further our understanding of the molecular mechanism of self-incompatibility, and possibly reveal the evolutionary origins of self-incompatibility and its genes. In the long term, the project should also enhance the ability of breeders to manipulate plant reproduction for crop improvement.

从口气到自我育种（近交）交配系统的转变是植物繁殖中最普遍的进化趋势之一。拟议的研究的一个主要目标是识别和表征进化转化为自我育的基因，从而了解植物物种生殖隔离的主要过程。在十字花序中，两个基因编码了S-钙化受体激酶SRK及其配体S-Ocus富含半胱氨酸的肽SCR，以防止自我授粉，因此负责自我兼容的（外部）交配方式。模型植物拟南芥是一种高度自我的物种，但是可以通过从其自我不合别的相对A. Lyrata中转移这两个基因来使其具有自包容性。发现塔利亚纳曲霉的天然种群在其SRK/SCR序列中表现出多态性，并具有隐藏的变化以表达自我不相容性，只能通过转移A. lyrata srk​​和SCR基因的转移来发现。对这种变异性的遗传和分子分析将首次允许对遗传诱发物种的自然种群近交的遗传学研究。预计该研究将深入了解物种形成期间或之后发生的交配系统的变化，进一步了解我们对自我不相容性分子机制的理解，并可能揭示了自我不相容性及其基因的进化起源。从长远来看，该项目还应增强育种者操纵植物繁殖以改善作物的能力。