HCG: Epihybridity in Zea Mays

HCG：玉米中的超杂交

• 批准号: 0923981
• 负责人: Jay Hollick
• 金额: $ 49.94万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2013-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0923981&HistoricalAwards=false
• 关键词: HCG; Epihybridity; Zea; Mays

PI: Jay Hollick (University of California - Berkeley)CoPI: William F. Tracy (University of Wisconsin - Madison)The general observation that hybrid offspring, in some manner or another, are larger than their parents is referred to as "hybrid vigor". Although this behavior serves to support much of the world's food supply, the biology behind this breeding behavior has remained remarkably intransient and the subject of much debate. The primary models accounting for hybrid vigor, and the reciprocal behavior of inbreeding depression, are based on the principles of Mendelian genetics. This project tests a novel model in which a form of non-Mendelian epigenetic inheritance contributes to these breeding behaviors. Epigenetic refers to heritable information that is adjunct to DNA, the widely recognized molecule of genetic transmission. "Epihybridity" is used here to describe that component of hybrid vigor attributable to dynamic changes in epigenetic sources of genomic, or epigenomic, variation. Field-based yield trials will be used to compare the extents of hybrid vigor and inbreeding depression occurring in normal corn (Zea mays) varieties versus derivatives in which the function of a specific molecule (RMR1) responsible for an RNA-based form of epigenetic inheritance is compromised. Primary studies indicate that RMR1 both enhances inbreeding depression and conditions parental genomes in ways that affect hybrid progeny traits. Using a high-resolution RNA sequencing approach, this project tests the idea that individual plants maintain unique RMR1-dependent small RNA populations and that hybrid progeny contain novel small RNA profiles that may specify gene expression patterns having complementary properties to growth and development. This project further uses an experimentally tractable example of hybrid vigor occurring at a single chromosome region responsible for producing plant pigments to identify specific DNA features that interface with this small RNA-based repression system. Understanding the nature of these features and this particular mechanism of eukaryotic genetics provides a novel perspective of RNA-based inheritance promising transformative impacts to the future of agriculture and human health.This project combines research groups from the Universities of Wisconsin (UW) and California (UCB), fostering scientific outreach across broad disciplines (epigenetics, genomics, and plant breeding) and providing education, scientific training and research experiences for a UCB graduate student, UW and UCB undergraduates, and high school students from the East Bay area. Minorities traditionally underrepresented in the sciences are engaged in these research activities through the support of existing high school and undergraduate programs promoting ethnic and socioeconomic diversity. The project will generate maize seed resources of potential interest to the hybrid seed industry [available from the project leader ([e-mail]) and from American Tissue Culture Collection (ATCC)], and academic researchers [available from the project leader and from the Maize Genetics Cooperation Stock Center (http://www.uiuc.edu/ph/www/maize)]. Nucleic acid sequence resources including small RNA profiles and limited genomic DNA sequence from an A619 inbred line will be generated and available for download from NCBI (http://www.ncbi.nlm.nih.gov/) or through a genome browser interface provided by MaizeGDB (http://www.maizegdb.org/). Data from the field trials will be made available through MaizeGDB. A BAC library representing the A619 inbred line will be constructed and available for community dissemination at cost by contacting the project leader. This BAC resource will likely provide material for an eventual genome resequencing project.

PI：Jay Hollick（加州大学伯克利分校）CoPI：William F. Tracy（威斯康星大学麦迪逊分校）一般观察到，杂交后代在某种程度上比其父母更大，这被称为“杂交活力”。尽管这种行为支持了世界上大部分的粮食供应，但这种繁殖行为背后的生物学原理仍然非常不稳定，并且是很多争论的话题。解释杂交活力和近交衰退的相互行为的主要模型是基于孟德尔遗传学的原理。该项目测试了一种新模型，其中一种非孟德尔表观遗传形式有助于这些育种行为。表观遗传是指附属于 DNA 的可遗传信息，DNA 是广泛认可的遗传传播分子。 “表观杂交”在此用于描述可归因于基因组或表观基因组变异的表观遗传来源的动态变化的杂交活力的组成部分。田间产量试验将用于比较正常玉米 (Zea mays) 品种与负责基于 RNA 的表观遗传形式的特定分子 (RMR1) 功能受到损害的衍生物中发生的杂种优势和近交衰退的程度。初步研究表明，RMR1 既会增强近交抑制，也会以影响杂交后代性状的方式调节亲本基因组。该项目使用高分辨率 RNA 测序方法，测试了这样的想法：单个植物维持独特的 RMR1 依赖性小 RNA 群体，并且杂交后代包含新颖的小 RNA 谱，这些谱可以指定与生长和发育具有互补特性的基因表达模式。该项目进一步使用一个实验上易于处理的混合活力例子，该例子发生在负责产生植物色素的单个染色体区域，以识别与这种基于小 RNA 的抑制系统相互作用的特定 DNA 特征。了解这些特征的本质以及真核遗传学的这种特殊机制，为基于 RNA 的遗传提供了新的视角，有望对农业和人类健康的未来产生变革性影响。该项目联合了来自威斯康星大学 (UW) 和加利福尼亚大学 (UCB) 的研究小组，促进跨学科（表观遗传学、基因组学和植物育种）的科学推广，并提供教育、科学培训和研究 为来自东湾地区的 UCB 研究生、UW 和 UCB 本科生以及高中生提供体验。传统上在科学领域代表性不足的少数群体通过现有高中和本科项目的支持，促进种族和社会经济多样性，参与这些研究活动。该项目将产生对杂交种子产业有潜在兴趣的玉米种子资源[可从项目负责人（[e-mail]）和美国组织培养物保藏中心（ATCC）获得]和学术研究人员[可从项目负责人和玉米遗传合作库存中心（http://www.uiuc.edu/ph/www/maize）获得]。将生成核酸序列资源，包括来自 A619 自交系的小 RNA 谱和有限的基因组 DNA 序列，并可从 NCBI (http://www.ncbi.nlm.nih.gov/) 或通过 MaizeGDB (http://www.maizegdb.org/) 提供的基因组浏览器界面下载。现场试验的数据将通过 MaizeGDB 提供。将建立一个代表 A619 自交系的 BAC 文库，并通过联系项目负责人以成本价用于社区传播。该 BAC 资源可能会为最终的基因组重测序项目提供材料。