EAGER: Evaluating a drought-driven hypothesis for the origin of obligate apomixis

EAGER：评估干旱驱动的专性无融合生殖起源假说

• 批准号: 2232106
• 负责人: Amanda Grusz
• 金额: $ 29.99万
• 依托单位: University of Minnesota Duluth
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2232106&HistoricalAwards=false
• 关键词: EAGER; Evaluating; drought; driven; hypothesis

Obligate apomixis—asexual reproduction by seed, spore, or egg—has evolved repeatedly across the tree of life, in diverse organisms ranging from animals (such as reptiles, insects, and fishes) to angiosperms (flowering plants) and other vascular plants. Despite its many origins, and intriguing ecological and evolutionary parallels among them, little is known regarding the causes and long-term consequences of this heritable reproductive syndrome. Some recent studies have proposed that drought, or periodic water limitation, could be key to driving the repeated evolution of obligate apomixis. This project unites environmental, developmental, and evolutionary data to evaluate the drought hypothesis, leveraging ferns as a model system. Ferns are ideal for this work because observing meiosis (i.e., the specialized cell division that produces spores/gametes) is easy and efficient compared to other organisms. Additionally, this study bridges generational gaps in technical expertise among next-generation researchers for a variety of cutting-edge and classical approaches; it stimulates interdisciplinary undergraduate, graduate, and postdoctoral research, emphasizing the value and relevance of museum specimens for addressing fundamental biological questions; and it expands international scientific collaborations in Mexico and Latin America. Furthermore, because obligate apomixis is highly coveted for, yet recalcitrant to, use in agricultural applications (as a tool for stabilizing optimal genotypes), this study has the potential to yield valuable insights with practical implications for humanity, especially regarding medicine and global food production. This research combines genetic, spatial, environmental, and life history data, across multiple evolutionary and ecological scales, for around 47 species comprising Myriopteris Fée, a well-supported clade in the fern subfamily Cheilanthoideae (Pteridaceae). Preliminary data are integrated with newly-gathered observations of reproductive traits (karyotype, gametophyte development, and spore size/number), climate and microhabitat, and a fully-sampled, time-calibrated phylogeny to rigorously interrogate the relationship between drought and the evolution of obligate apomixis. Specifically, these results are leveraged to address three main questions: Does phylogenetic inertia shape the distribution of obligate apomixis, or associated traits, within the focal clade? Does macroecological niche predict obligate apomixis among deserts of North America, including the Chihuahuan, Sonoran, and Mojave? And, is microhabitat significantly associated with obligate apomixis or its constituent traits across the focal clade? Importantly, this work also serves to resolve complex evolutionary relationships among diverse, previously undescribed, hybrid and polyploid lineages within Myriopteris.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.

专性无融合生殖通过种子、孢子或卵进行无性生殖在生命之树上反复进化，在从动物（如爬行动物、昆虫和鱼类）到被子植物（开花植物）和其他维管植物的各种生物中。尽管它有许多起源，以及它们之间有趣的生态和进化相似之处，但人们对这种遗传性生殖综合征的原因和长期后果知之甚少。最近的一些研究提出，干旱或周期性的水分限制可能是驱动专性无融合生殖重复进化的关键。该项目结合环境，发展和进化数据来评估干旱假设，利用蕨类植物作为模型系统。蕨类植物是这项工作的理想选择，因为观察减数分裂（即，产生孢子/配子的特化细胞分裂）与其他生物体相比是容易和有效的。此外，这项研究弥合了下一代研究人员在技术专业知识方面的代沟，以采用各种尖端和经典方法;它刺激了跨学科的本科生，研究生和博士后研究，强调了博物馆标本的价值和相关性，以解决基本的生物学问题;它扩大了墨西哥和拉丁美洲的国际科学合作。此外，由于专性无融合生殖在农业应用中（作为稳定最佳基因型的工具）是非常令人垂涎的，但又是不可接受的，因此这项研究有可能产生对人类具有实际意义的有价值的见解，特别是在医学和全球粮食生产方面。这项研究结合了遗传，空间，环境和生活史数据，在多个进化和生态尺度，约47种包括Myriopteris Fée，一个支持良好的分支在蕨类植物亚科Cheilanthoideae（蕨类）。初步数据与新收集的生殖特征（核型，配子体发育和孢子大小/数量），气候和微生境，以及一个完整的采样，时间校准的无性生殖的观察相结合，严格询问干旱和专性无融合生殖的演变之间的关系。具体而言，这些结果被用来解决三个主要问题：系统发育惯性形状的专性无融合生殖，或相关性状，在焦点分支的分布？宏观生态位能预测包括奇瓦瓦、索诺兰和莫哈韦在内的北美沙漠中的专性无融合生殖吗？而且，微生境是否与专性无融合生殖或其组成特征在整个焦点分支显着相关？重要的是，这项工作也有助于解决复杂的进化关系之间的多样性，以前未描述的，混合和多倍体谱系内Myriopteris.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持.