HCG: Epihybridity in Zea Mays

HCG：玉米中的超杂交

• 批准号: 1342475
• 负责人: Jay Hollick
• 金额: $ 2.2万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1342475&HistoricalAwards=false
• 关键词: HCG; Epihybridity; Zea; Mays

PI: Jay Hollick (Ohio State University)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(俄亥俄州立大学)Copi：William F.Tracy(威斯康星大学麦迪逊分校)一般观察到，杂交后代以这样或那样的方式比他们的父母更大，这被称为“杂交活力”。尽管这种行为支持了世界上大部分的食物供应，但这种繁殖行为背后的生物学仍然非常短暂，并成为许多争论的主题。解释杂交活力和近亲繁殖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的模型，在该模型中，一种形式的非孟德尔表观遗传有助于这些繁殖行为。表观遗传是指伴随DNA的可遗传信息，DNA是公认的遗传传递分子。“表观杂交性”在这里被用来描述可归因于基因组或表观基因组变异的表观遗传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普通玉米(Zea Mays)品种和衍生品种(负责基于RNA的表观遗传形式的特定分子(RMR1)的功能受损)的杂交活力和近交衰退的程度。初步研究表明，RMR1既增强了近交抑制，又通过影响杂交后代性状的方式调节了亲本基因组。使用高分辨率RNA测序方法，该项目测试了这样一种想法，即单个植物保持唯一的依赖于RMR1的小RNA群体，并且杂交后代包含新的小RNA图谱，这些图谱可能指定具有与生长和发育互补特性的基因表达模式。该项目进一步使用了一个发生在负责产生植物色素的单一染色体区域的杂交活力的实验易处理的例子，以确定与这种基于RNA的小抑制系统相连接的特定DNA特征。了解这些特征的本质和真核遗传学的这种特殊机制为基于RNA的遗传提供了一个新的视角，有望对农业和人类健康的未来产生变革影响。该项目结合了来自威斯康星大学(UW)和加州大学(UCB)的研究小组，促进了跨广泛学科(表观遗传学、基因组学和植物育种)的科学推广，并为UCB研究生、UW和UCB本科生以及来自东湾区的高中生提供教育、科学培训和研究经验。传统上在科学界代表性不足的少数群体通过支持现有的促进种族和社会经济多样性的高中和本科课程来从事这些研究活动。该项目将产生杂交种子行业可能感兴趣的玉米种子资源[可从项目负责人([e-mail])和美国组织培养库(ATCC)获得]，以及学术研究人员[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)].)获得将生成包括A619自交系的小核糖核酸图谱和有限基因组DNA序列在内的核酸序列资源，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实地试验的数据将通过MaizeGDB提供。将建立一个代表A619近交系的BAC文库，并通过与项目负责人联系，以成本价提供给社区传播。这个BAC资源可能会为最终的基因组重测序项目提供材料。