Collaborative Research: Hybrid Seed Inviability and the Evolution of Endosperm Development in Mimulus

合作研究：杂交种子的不存活性和酸浆菌胚乳发育的进化

• 批准号: 1558113
• 负责人: John Willis
• 金额: $ 50.5万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558113&HistoricalAwards=false
• 关键词: Collaborative; Research; Hybrid; Seed; Inviability

The seed of flowering plants contains two very important structures: the embryo that will become a seedling and eventually grow into the mature plant, and the endosperm, a tissue that provides nutrients to the embryo as it grows. If you have eaten rice, you have eaten endosperm, the starchy portion that fills the majority of the rice grain. Since the emergence of agriculture, humans have selected and bred seeds with a larger and starchier endosperm portion, ultimately creating the crop varieties we now depend upon. Endosperm, either directly or indirectly through animal feed, now provides an estimated 67% of the calories consumed by humans worldwide, and improving on these varieties remains of fundamental importance. Thus, from both an agricultural and food security perspective the development of the endosperm is critical to humankind's survival. This research will investigate the genes that control endosperm development and the molecular and evolutionary interactions between the endosperm and the embryo in the monkey flower (genus Mimulus). Although not eaten by humans, due to its ecological and evolutionary history, Mimulus provides a unique opportunity to study evolutionary and molecular aspects of the interactions between endosperm and embryo. As these interactions regulate the growth of the endosperm and thus the size of the nutritious portion of the seed in agricultural varieties, the results of this research in Mimulus are expected to engender a molecular understanding of a developmental process critical to human agricultural productivity. This research will inspire new high school biology teaching modules in genetics, evolution, and plant developmental biology that highlight the importance of the endosperm to humankind's diet, as well as the roles of pollinators and reproductive barriers in generating the diversity of life through the evolutionary process.Recent evidence links the evolutionary theory of parent-offspring conflict over maternal resources to the evolution of epigenetically imprinted genes controlling normal seed endosperm development. In interploidy hybrids, dosage-sensitivity of paternal and maternal allelic expression in developing endosperm is critical to normal development, and disruption leads to seed abortion. As yet it remains unknown whether such conflict over embryo provisioning leads to evolutionary divergence of imprinted genes or their targets, and ultimately hybrid seed lethality, in diploid species. The investigators propose to test this possibility by determining the genetic basis and evolutionary mechanisms underlying species divergence in endosperm development and leading to hybrid seed abortion, a principal isolating barrier in the Mimulus guttatus sp. complex. This research integrates genomic, molecular genetic and developmental biology approaches, utilizing high-throughput genome mapping, RNA sequencing technologies, and transgenic techniques to elucidate the genetic mechanisms contributing to seed abortion in M. guttatus x M. nudatus crosses. In so doing, it examines questions of fundamental interest to evolutionary biologists (how are new species formed?), and to developmental biologists (how is endosperm growth regulated?) while addressing a question of interest to both: what molecular changes might rapidly evolve when the mother's need to regulate growth and development differs from that of her offspring? Answering these questions will shed light on the developmental processes regulating endosperm growth and the evolutionary mechanisms driving divergence in flowering plants.

开花植物的种子包含两个非常重要的结构：将变成幼苗并最终生长成成熟植物的胚胎，而胚乳，一种随着胚胎的生长而提供营养的组织。如果您吃了米饭，就可以吃了胚乳，这是大部分米粒的淀粉部分。自从农业出现以来，人类已经选择并繁殖了种子，并以较大，饥饿的胚乳部分进行了选择，最终创造了我们现在依赖的农作物品种。直接或间接地通过动物饲料直接或间接地提供了胚乳，现在估计提供了全球人类消耗的卡路里的67％，并改善了这些品种的重要性。因此，从农业和粮食安全的角度来看，胚乳的发展对于人类的生存至关重要。 这项研究将研究控制胚乳发育的基因以及猴花（Mimulus属）中胚乳和胚胎之间的分子和进化相互作用。尽管不是人类食用的，但由于其生态和进化史，Mimulus为研究胚乳和胚胎之间相互作用的进化和分子方面提供了独特的机会。 由于这些相互作用调节了胚乳的生长，因此在农业品种中种子的营养部分的大小，预计这项研究的结果有望使对人类农业生产力至关重要的发育过程产生分子的理解。这项研究将激发新的高中生物学教学模块在遗传学，进化和植物发育生物学方面的重要性，强调了胚乳对人类饮食的重要性，以及授粉媒介和生殖障碍的作用和生殖障碍在产生生命的多样性中通过进化过程产生生命的多样性。正常种子胚乳发育。在相互植物的杂种中，父亲和母体等位基因表达在发育室中的剂量 - 敏感性对于正常发育至关重要，而破坏会导致种子流产。到目前为止，尚不清楚胚胎供应的这种冲突是否会导致二倍体物种中印记基因或其靶标的进化差异，并最终导致杂种种子致死性。研究人员建议通过确定胚乳发育中种类差异的遗传基础和进化机制来测试这种可能性，并导致杂种种子流产，这是Mimulus guttatus sp的主要分离屏障。复杂的。这项研究整合了基因组，分子遗传和发育生物学方法，利用高通量基因组映射，RNA测序技术和转基因技术来阐明在Guttatus X M. Nudatus M. Nudatus Crosses中导致种子流产的遗传机制。通过这样做，它研究了进化生物学家的基本兴趣问题（新物种是如何形成的？），以及发育生物学家（如何调节胚乳的增长？），同时解决这两者的兴趣问题：哪些分子变化可能会迅速发展，而何时母亲需要调节成长和发展与她的副词的相差？ 回答这些问题将阐明调节胚乳生长的发展过程以及驱动开花植物差异的进化机制。