CAREER: Genetic and epigenetic regulation of meiotic recombination in maize

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。植物育种依靠减数分裂重组将有利等位基因组合在一起，培育出具有高产和其他改良性状的作物。减数分裂重组是一个决定亲本染色体在有性生殖过程中如何配对和产生交叉以相互交换遗传物质的过程。由于新的和独特的等位基因组合，这使得一个个体与另一个个体不同。然而，育种者很少知道选择哪个性别方向的人工授粉，以获得他们需要的等位基因。为了帮助育种者确定最能提高其育种的授粉方向，本项目将比较玉米雄性和雌性减数分裂重组的频率，以了解减数分裂重组是否以及如何在性别之间有所不同。本项目产生的数据将用于开发两门生物信息学课程，面向对大数据科学和高级植物科学感兴趣的本科生和研究生。为了扩大项目影响，每年将举办为期5天的“植物科学中的生物信息学”夏季讲习班，重点是编程技能和前沿技术，以培训研究生，本科生，高中生，特别是女学生和来自代表性不足群体的学生。此外，高中科学教师将参与该项目，以帮助他们制定高中课程的科学项目。重组在促进植物遗传多样性和提高育种效率方面的作用已得到广泛认可。虽然在研究减数分裂重组的分子机制方面已经取得了巨大的进展，但遗传和表观遗传因素如何参与这一复杂的过程，以及玉米雄性和雌性减数分裂重组是否以及如何不同仍然知之甚少。本项目旨在利用玉米巢式关联定位（NAM）群体亲本与参考系B73的杂交后代，研究雌雄减数分裂重组过程。选择这些不育系来比较雄性和雌性减数分裂，因为它们最大限度地提高了整个玉米群体的遗传多样性。我们将首先确定在性别重组频率方面表现出最大差异的基因系（目标1），并生成这些基因系的高分辨率重组图，以比较全球和局部尺度上的性别交叉（目标2）。为了确定这种性别差异的原因，我们旨在阐明对减数分裂重组的调控重要的遗传和表观遗传因素（目的3）。除了使用NAM杂交外，还将使用RNA定向DNA甲基化途径中的突变体来特别剖析表观遗传修饰在减数分裂重组中的作用（目的3）。该项目包括一个综合教育部分，以扩大有利于研究生、本科生、高中生，特别是女学生和来自代表性不足群体的学生的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Plant breeding relies on meiotic recombination to combine favorable alleles to develop crops with high yield and other improved traits. Meiotic recombination is a process that determines how parental chromosomes pair up and generate crossovers during sexual reproduction in order to reciprocally exchange genetic material. This makes one individual different from another due to the new and unique combination of alleles. However, breeders rarely know which sex direction of artificial pollination to choose in order to obtain the alleles they need. In order to help breeders determine the direction of pollination that will most enhance their breeding, this project will compare the frequency of meiotic recombination between male and female in corn to understand whether and how meiotic recombination differs between the sexes. The data generated in this project will be used to develop two bioinformatics courses for undergraduate and graduate students who are interested in big data science and advanced plant science. To broaden project impact, a 5-day “Bioinformatics in Plant Science” summer workshop with an emphasis on programming skills and cutting edge technologies will be held annually to train graduate, undergraduate, high school students, and particularly female students and students from underrepresented groups. Additionally, high school science teachers will be involved in this project to help them develop science projects for high school curriculum.Recombination has been widely recognized for its role in promoting genetic diversity and largely impacts the efficiency of plant breeding. While enormous progress has been made to decipher the molecular mechanisms of meiotic recombination, how genetic and epigenetic factors are involved in this complicated process, and whether and how recombination differs between male and female meioses in maize are still poorly understood. This project seeks to investigate the meiotic recombination during male and female meioses by using the hybrids of parents of the maize nested association mapping (NAM) population with the reference line B73. These NAM lines were selected to compare male and female meioses because they maximize genetic diversity of the entire maize population. We will first identify the lines that show largest differences with respect to recombination frequency between sexes (Aim 1) and will generate high resolution recombination maps of these lines to compare crossovers between sexes at global and local scales (Aim 2). To determine the causes of such differences between sexes, we aim to elucidate genetic and epigenetic factors important for regulation and control of meiotic recombination (Aim 3). In addition to using the NAM hybrids, a mutant in a RNA directed DNA methylation pathway will be used to particularly dissect the roles of epigenetic modifications in meiotic recombination (Aim 3). This project includes an integrated education portion to broaden the impacts that will be beneficial to graduate, undergraduate, high school students, particularly female students and students from underrepresented groups.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.