CAREER: Genetic and epigenetic regulation of meiotic recombination in maize

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公共法律117-2)。植物育种依靠减数分裂重组结合有利的等位基因来培育高产和其他改良性状的作物。减数分裂重组是一个过程，它决定了在有性繁殖过程中，亲本染色体如何配对并产生交叉，以便相互交换遗传物质。这使得一个个体由于新的和独特的等位基因组合而不同于另一个个体。然而，繁育者很少知道应该选择哪种人工授粉的性别方向，以获得他们需要的等位基因。为了帮助育种者确定最能促进育种的授粉方向，该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存在差异。该项目产生的数据将用于为对大数据科学和高等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、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这个项目，帮助他们开发高中课程的科学项目。重组在促进遗传多样性方面的作用得到了广泛认可，并在很大程度上影响了植物育种的效率。尽管对减数分裂重组的分子机制的研究已经取得了很大的进展，但遗传和表观遗传因素如何参与这一复杂的过程，以及玉米雌雄减数分裂之间的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嵌套联合作图(NAM)群体的亲本与参照系B73杂交来研究减数分裂过程中的重组。选择这些NAM系来比较雄性和雌性减数分裂，是因为它们使整个玉米群体的遗传多样性最大化。我们将首先确定在性别间重组频率方面表现出最大差异的品系(目标1)，并将生成这些品系的高分辨率重组图，以比较全球和局部尺度上性别之间的交叉(目标2)。为了确定这种性别差异的原因，我们的目标是阐明对减数分裂重组的调控至关重要的遗传和表观遗传因素(目标3)。除了使用NAM杂交种外，还将使用RNA指导的DNA甲基化途径中的一个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(目标3)。该项目包括一个综合教育部分，以扩大对研究生、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NSF的法定使命，并通过使用基金会的智力优势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.