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来联合收割机组合有利的等位基因，从而培育出具有高产量和其他改良性状的作物。减数分裂重组是一个决定双亲染色体如何配对并在有性生殖过程中产生杂交以交换遗传物质的过程。这使得一个个体与另一个个体不同，因为等位基因的新的和独特的组合。然而，育种者很少知道选择哪个性向的人工授粉，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育种效果的授粉方向，该项目将比较玉米雄性和雌性之间减数分裂重组的频率，以了解两性之间减数分裂重组是否以及如何不同。该项目产生的数据将用于为对大数据科学和高级植物科学感兴趣的本科生和研究生开发两门生物信息学课程。为了扩大项目的影响，每年将举办为期5天的“植物科学中的生物信息学”暑期讲习班，重点是编程技能和尖端技术，以培训研究生、本科生和高中生，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，帮助他们开发高中课程的科学项目。植物育种因其在促进遗传多样性方面的作用而被广泛认可，并在很大程度上影响植物育种的效率。虽然已经取得了巨大的进展，以破译减数分裂重组的分子机制，遗传和表观遗传因素是如何参与这一复杂的过程，以及重组是否和如何在玉米雄性和雌性减数分裂之间的差异仍然知之甚少。本研究以玉米巢式关联作图（NAM）群体的亲本与参考系B73的杂交后代为材料，研究了玉米雌雄减数分裂过程中的减数分裂重组。选择这些NAM系来比较雄性和雌性减数分裂，因为它们使整个玉米群体的遗传多样性最大化。我们将首先确定性别间重组频率差异最大的品系（目标1），并生成这些品系的高分辨率重组图谱，以在全局和局部尺度上比较性别间的交叉（目标2）。要确定性别之间的差异的原因，我们的目标是阐明重要的调控和控制减数分裂重组的遗传和表观遗传因素（目的3）。除了使用NAM杂交体之外，RNA指导的DNA甲基化途径中的突变体将用于特别剖析减数分裂重组中表观遗传修饰的作用（Aim 3）。该项目包括一个综合教育部分，以扩大影响，这将有利于研究生，本科生，高中生，特别是女生和学生的代表性不足的群体。这个奖项反映了NSF的法定使命，并已被认为是值得支持的评估使用基金会的智力价值和更广泛的影响审查标准。

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.