ECA-PGR: Under the Hood: The Genetic Components of Maize Transformation

玉米是美国乃至全世界的主要粮食作物，是基础研究的重要模式。玉米产量在上个世纪经历了戏剧性的增长，但面临着进一步增加的挑战，特别是在高度多变的气候和疾病压力下。革命性的基因组工程工具(基因组编辑)为更好地理解遗传信息和特征之间的关系以及修改遗传特征以改进特征提供了巨大的机会。不幸的是，大多数农作物，包括玉米，不容易适应植物组织培养，从而限制了直接应用基因组编辑工具的好处。在这个项目中，一个适合培养的玉米品系的基因组将被测序，以便于识别调节可培养性的遗传因素。将开发新的方法来对复杂的玉米基因组进行遗传解码。特别是，一个可设计的细菌系统与玉米基因组中感兴趣的基因特别相互作用，将被用于研究基因功能和操纵细胞发育。该项目还将为本科生、研究生和博士后提供遗传学和计算方面的培训，重点是大数据教育。此外，该项目将与堪萨斯州路易斯·斯托克斯少数民族参与联盟合作，鼓励历史上代表性不足的学生参与STEM领域。玉米是美国农学价值最高的作物。基因组工程工具，包括TALENS和CRISPR，为阐明玉米的基因功能和性状改良提供了巨大的潜力。然而，目前玉米的遗传和基因组资源以及转化能力不足以充分利用基因组工程工具。该项目提供的公共资源包括高质量的可转化玉米自交系A188的基因组组装，以及A188与B73杂交产生的150个加倍单倍体(DH)系，一个转化顽固的自交系和玉米参考基因组。基于批量RNA测序的作图将用于胚胎发生和再生相关性状的遗传作图。此外，该项目将从愈伤组织细胞中生成时间序列转录组谱，这些愈伤组织细胞瞬时表达已知的胚胎发生和再生调节因子的设计转录激活器样效应器(DTALes)。这些图谱将被用来构建多层层级基因调控网络，以识别控制玉米胚胎发生和再生的高层级调控基因和中枢基因。异位基因表达和CRISPR-Cas9基因编辑将用于验证选定的候选基因。这些遗传和基因组资源将促进主要作物物种的基因组工程，并提高对玉米转化和再生能力的遗传基础的理解。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。

Maize (corn) is a staple crop in the US and worldwide, and serves as an important model for fundamental research. Maize production has experienced dramatic yield increases over the last century but faces challenges for further increases, particularly under highly variable climates and disease pressures. Revolutionary genome engineering tools (genome editing) offer great opportunities for improved understanding of the relationship between genetic information and traits, and for modifying genetic features for trait improvements. Unfortunately, most crop plants, including maize, are not readily amenable to plant tissue culture, thereby limiting the benefit from direct applications of genome editing tools. In this project, the genome of a maize line amenable to culture will be sequenced to facilitate the identification of the genetic elements that regulate culturability. Novel approaches will be developed for genetic decoding on the complex maize genome. In particular, a designable bacterial system specifically interacting with genes of interest in the maize genome will be utilized to study gene function and manipulate cell development. The project will also provide training for undergraduate, graduate and postdoctoral students in both genetics and computation, with an emphasis on large data education. In addition, the project will collaborate with the Kansas Louis Stokes Alliance for Minority Participation to encourage involvement of historically underrepresented students in STEM fields.Maize is the highest agronomically valued crop in the US. Genome engineering tools, including TALENs and CRISPRs, provide great potential for the elucidation of maize gene functions and trait improvements. However, current genetic and genomic resources as well as transformation capacity in maize are insufficient for the full utilization of genome engineering tools. This project provides public resources that include a high-quality genome assembly of a highly transformation amenable maize inbred line, A188, and 150 doubled haploid (DH) lines from a cross of A188 with B73, a transformation recalcitrant inbred variety and the maize reference genome. Bulked RNA sequencing based mapping will be used for genetic mapping of traits related to embryogenesis and regeneration. Furthermore, the project will generate time-series transcriptome profiles from callus cells that are transiently expressing designer Transcription Activator-Like effectors (dTALes) of a known regulator of embryogenesis and regeneration. These profiles will be used to construct multilayered hierarchical gene regulatory networks to identify high hierarchical regulators and hub genes that govern maize embryogenesis and regeneration. Ectopic gene expression and CRISPR-Cas9 gene editing will be used to validate select candidate genes. These genetic and genomic resources will advance genome engineering in a major crop species and improve understanding of the genetic basis of maize transformation and regeneration ability.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.