Mechanism of Dioecy Determination in Diospyros

大多数植物是雌雄同体，这意味着它们同时携带雄性和雌性器官。有些植物，如西红柿、水稻、豆类和其他栽培品种，在同一朵花中，花粉从雄性器官投到雌性器官。另一些则采用巧妙的方法来确保一个个体为另一个个体的花授粉。柿子、开心果、猕猴桃、啤酒花和菠菜是少数几个在不同个体中发现这些功能的植物物种，这种情况被称为雌雄异株。哺乳动物的雄性或雌性是由X和Y染色体决定的：雄性有一个X和一个Y，雌性有两个X。Y染色体上的一个基因负责触发男性特征的发育。大多数雌雄异株植物类似于人类系统，有XY个雄性和XX个雌性。但是，究竟是什么基因决定了一种特定植物的花是雄花还是雌花，这一直是个谜。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。在雌性中，MeGI的含量很高，就像一种绝育剂，抑制花粉的形成。在男性中，OGI可以防止MeGI的积累。柿子OGI-MeGI系统的发现为植物育种开辟了新的可能性。控制花器官对选育自交系的控制杂交产生高产杂交种也很重要。更广泛的影响包括旨在提高背景不足的高中生或大学生对大数据分析的技能和信心的推广。此外，由于雌雄异株在植物中独立进化了许多次，这项工作为植物是否发明了类似或不同的解决方案来解决相同的问题提供了基础。这些结果揭示了植物Y染色体的组织结构，并为薯蓣种属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，以及提出更多关于雌雄异株物种雌雄异株决定进化的一般问题。他们的具体目标是：1)利用测序和遗传学的结合方法确定莲藕的Y染色体；2)利用转基因技术在拟南植物中揭示OGI和MeGI的分子功能；3)表征薯蓣及其近缘物种Y染色体雌雄异株决定区域的变异，并测试类似的系统是否在其他雌雄异株系统中起作用。这项工作为揭示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，这对人类的生存和福祉至关重要。

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.