EAGER: Development of tools for probing the role of DNA methylation in maize

技术的进步使科学家们对许多作物物种的基因组有了全面的了解。然而，将植物基因组的差异与特定性状联系起来仍然存在挑战。由于缺乏研究表观遗传变异的工具，即不由DNA序列变化引起的可遗传变异，限制了我们预测种子大小和产量等植物性状的能力。该项目正在开发新的工具和方法来研究表观遗传变异在玉米中的作用。这些工具需要开发一种系统，用于有针对性地编辑调控植物表观遗传变异的基因，从而能够深入了解表观遗传变异在作物发育中的作用。该项目的成果将为改良玉米和其他作物提供突破性技术。今后的研究重点是开发生物材料来研究DNA甲基化在玉米中的作用。先前的研究表明，DNA甲基化是玉米正常发育所必需的。该项目将描述玉米愈伤组织DNA甲基化的全基因组模式，以记录这种细胞类型的任何变化。基因组编辑方法将用于在细胞培养中的三个关键DNA甲基化途径中创建功能丧失突变。这些细胞系可以用来记录基因或转座因子表达的变化，从而深入了解DNA甲基化在表达调控中的作用。一些已知在DNA去甲基化中起作用的酶也会在愈伤组织中过度表达，以试图产生部分或特定位点的DNA甲基化减少。将尝试恢复含有功能丧失突变或过度表达DNA去甲基化酶的植物，用于研究这些变化对营养植物组织的影响。该项目产生的材料可能为理解DNA甲基化在具有大而复杂的作物基因组的物种中的作用提供新的资源。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。

Technological advances have enabled scientists to develop complete understanding of the genomes of many crop species. However, there are continued challenges in linking the differences in plant genomes to specific traits. The lack of tools to study epigenetic variation, heritable variation that is not due to changes in DNA sequence, limits our ability to predict plant traits such as seed size and yield. This project is developing novel tools and approaches for studying the role of epigenetic variation in corn. These tools require developing a system for targeted editing of genes that regulate epigenetic variation in plants, enabling insights into the role of epigenetic variation in crop development. The outcomes of this project will provide breakthrough technologies to improve corn and other crops.The proposed research is focused on development of biological materials to study the role of DNA methylation in maize. Prior work has suggested that DNA methylation is required for proper development of maize. This project will characterize the genome-wide patterns of DNA methylation in callus of maize in order to document any changes in this cell type. Genome editing approaches will be utilized to create loss-of-function mutations in three key DNA methylation pathways in cell culture. These cell lines can then be used to document changes in gene or transposable element expression to provide insights into the roles of DNA methylation in regulation of expression. Several enzymes known to play roles in demethylation of DNA will also be over-expressed in callus tissue in an attempt to generate partial, or locus-specific, reductions in DNA methylation. Attempts will be made to recover plants containing the loss-of-function mutations or over-expressing DNA demethylases that would be used to study the effects of these changes in vegetative plant tissues. The materials generated by this project may provide novel resources for understanding the role of DNA methylation in a species with a large, complex crop genome.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.