Examining the correlated molecular mechanisms of self and heterospecific pollen-pistil recognition

开花植物展示它们迷人的花朵，并为传粉者或风带来繁殖的花粉做好准备。确定植物如何成功繁殖需要了解雌性生殖器官(雌蕊)如何识别和接受高质量的花粉，同时拒绝低质量的花粉的分子机制。雌蕊和花粉的识别对于植物的两个重要的交配选择具有重要意义--区分自体和非自体花粉，以及来自同一物种的花粉和来自不同物种的花粉。本研究探讨了原产于德克萨斯州的野生花卉Phlox drummondii的自体花粉排斥和异种花粉排斥的分子机制。在该物种中，雌蕊识别和拒绝自体和外来花粉的能力存在广泛的自然变异，这两种识别系统的变异在个体之间高度相关。这项研究涉及到导致花粉-雌蕊识别的分子机制以及不亲和性之间相关性的原因的详细遗传学研究。具体地说，这项研究结合了对不亲和性变异的定量遗传解剖、全基因组基因表达分析和人工选择实验，以发现在一个物种中花粉-雌蕊相互作用的新机制，该物种独立于模式植物系统中发现的那些自我和外来不亲和性进化。这项研究将得到与当地自然历史博物馆有关的外联活动的补充。科学家们将为中小学生创建教育活动，为教师提供关于花卉多样性的专业发展研讨会，并组织植物科学的公开讲座。本项目通过剖析非模式野生花种内不亲和性变异的分子基础，研究了长期存在的假说，即自体和异种花粉-雌蕊不亲和性系统是机械联系在一起的。具体地说，这项研究将确定自我和异种识别是否具有共同的遗传机制，自我和异种不亲和性的崩溃是否涉及多个基因，包括自我同一性基因以外的基因，以及自我和异种不亲和性之间的相关性是否会限制花粉-雌蕊识别的进化。为了实现这些目标，本研究将通过全基因组基因表达分析来确定不亲和性背后的分子机制，通过遗传作图实验来表征自体和异种花粉识别崩溃的遗传结构，并使用人工选择实验来量化不亲和性之间的相关性所施加的遗传约束。这项综合研究将测试关于植物不亲和性遗传基础的具体假设，同时发现识别花粉-雌蕊的新机制。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Flowering plants display their charismatic flowers open and ready for pollinators or wind to bring pollen for reproduction. Determining how plants successfully reproduce requires understanding the molecular mechanisms underlying how female reproductive organs (pistils) recognize and accept high quality pollen while rejecting low quality pollen. The recognition between pistils and pollen is significant for two important mate choices in plants - distinguishing between self-pollen and non-self-pollen as well as between pollen from the same species and pollen from different species. This research investigates the molecular mechanisms underlying self-pollen reject and foreign-species pollen rejection in Phlox drummondii, a native Texas wildflower. In this species there is extensive natural variation in the ability of pistils to recognize and reject self and foreign pollen and the variation in these two recognition systems is highly correlated across individuals. This research involves a detailed genetic investigation of molecular mechanisms causing pollen-pistil recognition and the causes of the correlation between incompatibilities. Specifically, this research combines quantitative genetic dissection of variation in incompatibilities, with genome-wide gene expression analyses, and an artificial selection experiment to discover new mechanisms of pollen-pistil interactions in a species that has evolved self and foreign incompatibly independently of those found in model plant systems. This research will be complemented by outreach activities associated with the local natural history museum. The scientists will create educational activities for elementary and high school students, provide teacher professional development workshops about floral diversity, and organize public lectures on plant science. This project investigates the long-standing hypothesis that self and heterospecific pollen-pistil incompatibility systems are mechanistically linked by dissecting the molecular basis of variation in incompatibility within a non-model wildflower species. Specifically, this research will determine if self and heterospecific recognition share genetic mechanisms, if the breakdown of self and heterospecific incompatibility involves multiple genes including genes outside the self-identity locus, and if the correlation between self and heterospecific incompatibility could constrain the evolution of pollen-pistil recognition. To accomplish these goals, this research will determine the molecular mechanisms underlying incompatibly through whole-genome gene expression analyses, characterize the genetic architecture of the breakdown of self and heterospecific pollen recognition through genetic mapping experiments, and quantify the genetic constraint imposed by the correlation between incompatibilities using an artificial selection experiment. This integrative research will test specific hypotheses about the genetic basis of incompatibly in plants while discovering new mechanisms of pollen-pistil recognition.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.