The Origin and Evolution of Y Chromosomes in Caricaceae

番薯科Y染色体的起源与进化

• 批准号: 0922545
• 负责人: Ray Ming
• 金额: $ 379.62万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0922545&HistoricalAwards=false
• 关键词: Origin; Evolution; Chromosomes; Caricaceae

PI: Ray R. Ming (University of Illinois at Urbana-Champaign)CoPIs: Paul H. Moore (Hawaii Agriculture Research Center), Richard C. Moore (Miami University) and Qingyi Yu (Texas A&M University)Sex expression in papaya (Carica papaya L.; Family Caricaceae) is controlled by loci found in the male specific region of the Y chromosome (MSY). Unlike the sex chromosomes of other plants or animals, the MSY of papaya is quite small and is restricted to a region about 8 Mb in size. In addition, sex reversal mutants in papaya indicate that the two sex determination genes are confined to a smaller region of about 1 Mb that is currently being sequenced. Thus the small size of the sex determination region in papaya offers the opportunity to dissect the early events in sex chromosome evolution and the identification of sex determination genes feasible. The long-term goal of this project is to understand the evolutionary mechanisms governing the formation and divergence of sex chromosomes. To accomplish this objective, 300 bacterial artificial chromosomes (BACs) from the sex specific regions of six species in three genera of Caricaceae will be sequenced and subjected to detailed functional and comparative genome analyses. The specific objectives are to: 1) identify the sex determination genes in C. papaya. The focus will be on candidate genes in the 1 Mb deleted region of the male to female sex reversal mutants to identify the two sex determination genes; 2) elucidate the origin of sex chromosomes in Caricaceae. A comparative genomic approach using chromosome sequences of six species from three genera with diverse breeding systems to determine whether the sex chromosomes of papaya share a similar evolutionary history with the homologous regions in these sister species; 3) determine the forces that have shaped genome evolution of papaya sex chromosomes. Competing evolutionary hypotheses concerning the deterioration of the MSY will be distinguished by conducting population genomics analyses across the entire region and the corresponding region on the X chromosome; and 4) engineer true breeding hermaphrodite papaya varieties to validate the function of the sex determination genes. Candidate gene(s) promoting stamen development will be transformed into female plants of leading papaya cultivars to produce hermaphrodite varieties without the Yh chromosome. This project will significantly advance genomic tools and knowledge for tropical trees, an under-explored node of the angiosperms that is of large and growing importance to US agriculture. The knowledge gained may enable the engineering of true breeding hermaphrodite papaya varieties and improve papaya fruit productivity while lowering the cost. With respect to training and outreach, the four institutions participating on this project, University of Illinois at Urbana-Champaign (UIUC), Hawaii Agriculture Research Center (HARC), Texas A&M University (TAMU) and Miami University (MU) each has strong teaching, training, and outreach programs with a successful history of engaging high school, undergraduate, and graduate students, including at all levels and minority groups that are under-represented in the sciences. College and high school students will be trained through summer intern programs at UIUC, HARC, TAMU, and MU. Graduate students and postdoctoral scientists will be exposed to new genomic tools and techniques. Knowledge of plant genomics will be communicated to the general public as well through participation in outreach programs such as the Annual Hawaii State Farm Fair.

PI：Ray R. Ming（伊利诺伊大学Urbana-Champaign大学）COPIS：Paul H. Moore（夏威夷农业研究中心），Richard C. Moore（迈阿密大学）和Qingyi Yu（德克萨斯州A＆M University）在Papaya（Carica Papaya L。; Family Caricaceae）在Papaya（CariCA）在loce papaya的性别表达（Caros carlos）是男性的。与其他动植物的性染色体不同，木瓜的MSY很小，仅限于大约8 MB的区域。此外，木瓜中的性逆转突变体表明，两个性别测定基因仅限于当前正在测序的约1 MB的较小区域。因此，木瓜中的性别确定区域的尺寸很小，为剖析性染色体进化的早期事件和可行的性确定基因的鉴定提供了机会。 该项目的长期目标是了解有关性染色体形成和差异的进化机制。为了实现这一目标，将对三个富特（Caricaceae）属的六种性别区域的300个细菌人工染色体（BAC）进行测序，并进行详细的功能和比较基因组分析。 具体目标是：1）确定木瓜木瓜中的性别确定基因。重点将放在男性到女性性逆转突变体1 MB删除区域中的候选基因，以鉴定两个性别确定基因。 2）阐明钙科中性染色体的起源。使用来自三个具有不同育种系统的六种物种的染色体序列的比较基因组方法，以确定木瓜的性别染色体是否与这些姊妹物种的同源区域具有相似的进化史； 3）确定帕帕亚性染色体的基因组进化的力。关于MSY恶化的竞争进化假设将通过在整个地区进行种群基因组学分析以及X染色体的相应区域进行区分； 4）工程师真正育种雌雄同体的木瓜品种来验证性别确定基因的功能。促进雄蕊发育的候选基因将转变为主要的木瓜品种的雌性植物，以产生没有YH染色体的雌雄同体品种。 该项目将大大推动热带树木的基因组工具和知识，这是一个不足的被子植物节点，对美国农业而言却越来越重要。 获得的知识可以使真正育种雌雄同体的木瓜品种的工程能够提高木瓜水果生产力，同时降低成本。 With respect to training and outreach, the four institutions participating on this project, University of Illinois at Urbana-Champaign (UIUC), Hawaii Agriculture Research Center (HARC), Texas A&M University (TAMU) and Miami University (MU) each has strong teaching, training, and outreach programs with a successful history of engaging high school, undergraduate, and graduate students, including at all levels and minority groups that are在科学中的代表性不足。大学和高中生将通过UIUC，HARC，TAMU和MU的暑期实习计划进行培训。研究生和博士后科学家将接触到新的基因组工具和技术。植物基因组学的知识也将通过参加夏威夷州一年一度的外展计划来传达给公众。