Mechanism of Dioecy Determination in Diospyros

黑枣雌雄异株的决定机制

• 批准号: 1457230
• 负责人: Isabelle Henry
• 金额: $ 79.14万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457230&HistoricalAwards=false
• 关键词: Mechanism; Dioecy; Determination; Diospyros

Most plants are hermaphrodites, which means that they carry both male and female organs. Some, like tomato, rice, beans and other cultivated species, cast pollen from male to female organs in the same flower. Others employ ingenious schemes to ensure that one individual pollinates the flower of another. Persimmon, pistachio, kiwi, hops, and spinach are amongst the few percent of plant species in which these functions are found in separate individuals, a condition called dioecy. In mammals maleness or femaleness are determined by X and Y chromosomes: males have an X and a Y and females have two Xs. A single gene on the Y is responsible for triggering the development of male traits. Most dioecious plants resemble the human system, with XY males and XX females. But what gene(s) may be responsible for determining whether a particular plant carries male or female flowers has been a long-standing mystery. Recently, the authors combed through the genomes of persimmon trees looking for genes that were exclusive to males and found pair of genes, called OGI and MeGI. In females, MeGI builds to high level and acts like a neutering agent, repressing pollen formation. In males, OGI prevents the accumulation of MeGI. Discovery of the OGI-MeGI system in persimmon opens up new possibilities in plant breeding. Controlling flower organs is also important for facilitating production of high yielding hybrids from controlled hybridization of selected inbreds. Broader impacts include an outreach aimed at increasing skills and confidence in Big Data Analysis for high school or early college students of underpresented background. Additionally, because dioecy evolved independently many times in plants, this work provides a foundation to ask whether plants invented similar or different solutions to the same problem.These results cast light on the organization of a plant Y chromosome and provide a working model for dioecy determination in Diospyros species. The authors aim to capitalize on these findings to further investigate the molecular function of the OGI and MeGI genes, as well as ask more general questions about the evolution of dioecy determination in dioecious species. Their specific objectives are to: 1) Define the Y chromosome in Diospyros lotus using a combination of sequencing and genetic approaches 2) Unravel the molecular function of OGI and MeGI using transgenic technology in A. thaliana and genome-wide genomic analyses in Diospryros and 3) Characterize variation in the Y-chromosome dioecy determination region in Diospyros and closely-related species and test whether similar systems are at play in other dioecious systems. This work provides a model for unraveling dioecy determination systems in economically-relevant plant species, an area important for human sustenance and well being.

大多数植物是两性的，这意味着它们同时携带雄性和雌性器官。有些植物，如番茄、水稻、豆类和其他栽培物种，在同一朵花中从雄性器官向雌性器官散播花粉。其他人则采用巧妙的方案来确保一个个体给另一个个体的花授粉。柿、开心果、猕猴桃、啤酒花和菠菜是少数几种在不同个体中具有这些功能的植物中的一种，这种情况被称为雌雄异株。在哺乳动物中，雄性或雌性由X和Y染色体决定：雄性有一个X和一个Y，雌性有两个X。Y上的一个单基因负责触发男性特征的发育。大多数雌雄异株植物与人类系统相似，有XY雄株和XX雌株。但是，什么基因(S)可能负责决定一种特定的植物是开雄花还是开雌花，这一直是一个谜。最近，作者梳理了柿树的基因组，寻找雄性独有的基因，发现了一对基因，称为OGI和MeGI。在女性体内，MeGI的水平很高，就像绝育一样，抑制了花粉的形成。在男性中，OGI可以防止MeGI的蓄积。OGI-MeGI系统在柿中的发现为植物育种开辟了新的可能性。控制花器官也是促进由选定自交系控制杂交产生高产杂交种的重要因素。更广泛的影响包括一项旨在提高大数据分析技能和信心的外展活动，面向背景较低的高中生或大学预科学生。此外，由于雌雄异株在植物中多次独立进化，这项工作为研究植物对相同问题的解决方案是相似的还是不同的提供了基础。这些结果揭示了植物Y染色体的组织，并为柿属物种的雌雄异株的确定提供了一个工作模型。作者的目标是利用这些发现进一步研究OGI和MeGI基因的分子功能，并提出关于雌雄异株物种雌雄异株决定进化的更一般问题。他们的具体目标是：1)结合测序和遗传方法确定柿Y染色体；2)利用转基因技术揭示OGI和MeGI的分子功能；3)鉴定Y染色体雌雄异株决定区域在柿及近缘物种中的变异，并测试类似系统是否在其他雌雄异株系统中发挥作用。这项工作为解开与经济相关的植物物种的雌雄异株决定系统提供了一个模型，这是一个对人类生存和福祉至关重要的领域。