Excellence in Research: Developing a Model System for Studying the Determinants of Flower Morphology in Tropical Dioecious Trees

在许多植物物种中，人们可以发现雄花和雌花在单独的植物上，或者在同一植物上，或者在单花上同时携带雄蕊（雄性）和雌蕊（雌性）部分。遗传和环境在决定这类植物的花型和花器官发育方面的相互作用在很大程度上仍未得到研究。为了研究这一现象，项目团队将使用一种原产于佛罗里达南部、加勒比地区、墨西哥南部和中美洲新热带沿海地区的木樱。它是一种重要的原生热带树木，具有上述不同程度的花卉图案。研究小组将对这种植物的基因组进行测序，并分析在野生种群中发现的基因和开花模式，以确定在调节花和花器官发育中起作用的基因组区域。这些实验、数据收集和分析将为培养基因组学、生物信息学、生物数据科学和生物保护领域的研究生和本科生提供极好的机会和来源材料。在雌雄异株分类群中，决定雌蕊和雄蕊生物个体的因素和机制尚不清楚。在少数情况下，异型染色体已被确定为一个主要的决定因素。在其他情况下，环境因素已被确定为主要决定因素。然而，即使这些案例似乎也没有确定严格的决定因素。此外，研究这些现象的生物系统绝大多数是草本和温带的。该项目旨在研究遗传和环境的相互作用，以确定具有可变花表达的热带树木的雌蕊和雄蕊个体。该项目将(1)利用短读和长读DNA测序结合近端结扎技术，对研究分类单元Coccoloba varfolia的完整核基因组进行组装和注释；(2)通过群体取样、浅全基因组鸟枪测序和形态特异性reads鉴定，确定有助于确定雌蕊或雄蕊个体的遗传区域。(3)通过记录南弗罗里达不同种群花形态与环境条件的关系，评价环境对花形态的影响。项目团队将为来自服务欠缺社区的学生提供体验式学习、基因组学和生物信息学方面的培训和技能发展机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In many plant species, one can find presence of male and female flowers on separate plants or on same plants or single flowers carrying both the stamens (male) and pistil (female) parts. The interplay between genetics and the environment in determining the flower type and development of floral organs in such plants remains largely uninvestigated. To study this phenomenon, the project team will use Coccoloba diversifolia (pigeonplum), a native of neotropical coastal areas of Southern Florida, Caribbean, Southern Mexico and Central America. It is an important native tropical tree and shows a varying degree of flower patterns mentioned above. The team will sequence the genome of this plant species and profile the genetics and flowering patterns found in a wild population to identify the regions of genome that play a role in regulating the development of flowers and floral organs. The proposed experiments, data collection and analyses will provide an excellent opportunity and source material to train the graduate and undergraduate students representing the full spectrum of diverse talent in genomics, bioinformatics, biological data science and conservation. Among dioecious taxa, the factors and mechanisms determining which biological individuals are pistillate and which are staminate are still not well understood. In a small minority of cases, heteromorphic chromosomes have been identified as one major determinant. In other cases, environmental factors have been identified as major determinants. Yet even these cases appear not to identify strict determinants. Moreover, the biological systems in which these phenomena are studied, have been overwhelmingly herbaceous and temperate. The project looks to examine the interplay of genetics and the environment in the determination of pistillate and staminate individuals in a tropical tree with variable floral expression. The project will (1) assemble and annotate the complete nuclear genome of the study taxon Coccoloba diversifolia using a combination of short- and long-read DNA sequencing along with proximity ligation, (2) identify the genetic regions contributing to the determination of pistillate or staminate individuals through population sampling, shallow whole genome shotgun sequencing and the identification of morphology-specific reads, and (3) assess the contribution of environment in determining flower morphology through the documentation of flower morphology ratios in relation to environmental conditions for populations of C. diversifolia in South Florida. The project team will provide training and skills development opportunities to students from underserved communities on experiential learning, genomics, and bioinformatics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.