Collaborative research: The Evolutionary Genetics of Pollen-Pistil Incompatibility and Reproductive Isolation in Zea mays

合作研究：玉米花粉雌蕊不相容性和生殖隔离的进化遗传学

• 批准号: 1754098
• 负责人: Jeffrey Ross-Ibarra
• 金额: $ 31.97万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1754098&HistoricalAwards=false
• 关键词: Collaborative; research; Evolutionary; Genetics; Pollen

Because hybridization between plant species often results in offspring with reduced fitness, it remains a mystery why hybridization persists and is even fairly common in nature. To address this fundamental question, this research investigates genes that control the mating compatibility between individuals. These genes are distributed differently among populations of corn and its wild ancestor, teosinte. Although these are parts of the same species, Zea mays, they represent distinct subspecies and some populations of these subspecies interbreed easily and others do not. This system serves as a valuable genetic model to investigate the problem of hybridization and especially an overlooked conflict between males and females of the plant species. While females that reject pollen from the wrong species avoid producing low quality offspring (avoiding hybridization), males with pollen that can fertilize, and produce even low quality offspring with closely related species or subspecies will have higher fitness (promoting hybridization). By identifying and studying the genes underlying mating compatibility in this well-studied and economically important plant, this project may determine the forces that allow or prevent species from avoiding hybridization. This research combines computational, mathematical, and genetic approaches to address these questions. The research team will train undergraduates, graduate students, and postdoctoral researchers in California and Minnesota. They will also develop classroom materials for K-12 students in California and offer Biomath summer camps for high school girls in Minnesota.This research addresses how interactions between the pollen and style shape the ability of a plant to reject pollen from the wrong species. The project also addresses how pollen may overcome this barrier. The work begins with a population genetic model of this process, and asks which parameters allow for females to effectively reject pollen from another subspecies, and which parameters allow pollen to overcome this barrier. A second component of the work involves the fine mapping of one of the three gametophyte factors that modulate cross compatibility between populations of Zea mays subspecies so that the DNA sequence context around all three gametophyte factors is known. Researchers will then conduct a series of genetic crosses to identify the frequency of alternative alleles at the gametophyte factor loci in different sympatric maize and mexicana-type teosinte populations in the Mexican highlands. Finally, these alleles will be sequenced, allowing the researchers to evaluate the predictions of their mathematical model.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.

由于植物物种之间的杂交通常会导致降低适应性的后代，因此杂交持续存在，甚至在自然界中相当普遍的原因仍然是一个谜。为了解决这个基本问题，这项研究研究了控制个人之间交配兼容性的基因。这些基因在玉米及其野生祖先Teosinte中的分布不同。尽管这些是同一物种的一部分，但它们代表了不同的亚种，并且这些亚种的某些种群很容易杂交，而其他亚种则没有。该系统是研究杂交问题的宝贵遗传模型，尤其是植物物种的男性与女性之间的冲突。尽管拒绝错误物种的花粉的女性避免产生低质量的后代（避免杂交），但可以施肥的花粉的雄性可以施肥，甚至具有紧密相关物种或亚种的低质量后代将具有更高的适应性（促进杂交）。通过识别和研究这种研究良好且经济重要的植物中交配兼容性的基因，该项目可以确定允许或防止物种避免杂交的力。这项研究结合了计算，数学和遗传方法来解决这些问题。研究小组将在加利福尼亚和明尼苏达州培训本科生，研究生和博士后研究人员。他们还将为加利福尼亚的K-12学生开发课堂材料，并为明尼苏达州的高中女生提供Biomath夏令营。这项研究介绍了花粉和风格之间的相互作用如何塑造植物拒绝从错误物种中拒绝花粉的能力。 该项目还解决了花粉如何克服这一障碍。这项工作始于此过程的人群遗传模型，并询问哪些参数允许女性有效拒绝其他亚种的花粉，哪些参数允许花粉克服该障碍。 工作的第二个组成部分涉及对Zea Mays亚种群种群调节跨兼容性的三个配子体因子之一的精细映射，以便已知所有三个配子体因子围绕所有三个配子体因子的DNA序列上下文。然后，研究人员将进行一系列遗传杂交，以确定在墨西哥高地的不同同学玉米和墨西哥型Teosinte种群中的Gametophyte因子基因座的替代等位基因的频率。最后，这些等位基因将进行测序，使研究人员能够评估其数学模型的预测。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响评估的评估来获得支持的。