BRC-BIO: The transcriptomics of environmentally-controlled differentiation into male or female in plants

植物通过雄性和雌性的功能繁殖，就像动物一样。然而，与动物不同的是，大多数植物(~90%)在一个个体中结合了雄性和雌性的功能。尽管只有不到10%的植物物种具有分离的雌雄，但这种植物交配系统在绿色植物的历史上反复进化，为理解其进化提供了机会。此外，许多重要的经济作物有不同的雄性和雌性，通常雄性或雌性比另一种更有价值(例如雌性冬青、雄性银杏)，在成熟之前很难区分它们。在其他情况下，保持雄性和雌性的分离和稳定(例如雌性大麻、雌性啤酒花)对于保持产品的质量是必要的。尽管植物生物学的这一方面在经济上很重要，但我们对决定植物这种表达的因素知之甚少。这个项目将研究一组特殊的植物，这些植物表现出不同的雄性和雌性--那些环境控制着雄性或雌性功能的表达。决定雄花或雌花类型的染色体在环境起很大作用的植物和物种中很少见，它们有能力表达雄花或雌花，并在它们的一生中从一朵花变成另一朵花。基因表达的变化可能是控制这些物种这种表型的最可能的机制，因此，本研究探讨了枫树基因表达与花发育的关系，并与不同植物交配系统的其他植物进行了比较。更多地了解基因表达如何与雄花和雌花的表达有关，将有助于在面对气候变化时做出更经济的决定和种群稳定的计划。该项目还涉及以课程为基础的本科生研究经验的发展，其中包括现代基因技术和分析方面的领域要素和培训。它还涉及以进化生物学为重点的局部推广。从历史上看，决定生物体中男性和女性功能的几种机制已被分类：遗传、社会、温度依赖和环境。这种划分导致了对怀疑具有环境决定权的物种进行的主要基于生态的研究，并强化了遗传学和环境之间的错误二分法。这个项目调查了花功能中基于环境的可塑性的转录基础，并寻求以下问题的答案。1.与花型表达相关的基因表达的数量和种类是否存在差异？2.在花发育过程中转录组的变化有多大？3.具有这种可塑性的物种的转录图谱与其他物种相比有多相似？它是更类似于雌雄同体还是雌雄同体？通过这项工作，将对基因激活和活性如何响应环境来塑造花型有新的理解。随着气候的变化，这种理解变得更加关键。此外，这项拟议的研究解决了关于植物交配系统进化的长期存在的问题。虽然环境控制花的表型经常被认为是雌雄异株的潜在途径，但还没有研究探索这些物种与那些具有雌雄同株或雌雄异株交配系统的物种在转录上的相似性。这阻碍了我们对雌雄异株途径的理解，雌雄异株是植物中一种重要的、重复的进化转变。类似的动物进化转变在进化时间上发生得太少太早，不利于实验研究，所以如果我们想了解雌性和雄性是如何以及为什么起源的，我们最好的机会可能在于对植物的研究。这个奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Plants reproduce via male and female functions much like animals do. Differently from animals, however, most plants (~90%) combine male and female function in one individual. Even though less than 10% of plant species have separate males and females, this plant mating system has evolved repeatedly in the history of green plants and provides an opportunity to understand its evolution. Moreover, many economically important crops have separate males and females, and often the male or the female is more valuable than the other (e.g., female holly, male gingko), and they can be difficult to distinguish before maturity. In other situations, keeping males and females separate and stable (e.g., female Cannabis, female hops) is necessary to maintain the quality of a product. Despite the importance of this aspect of plant biology economically we know little about factors that determine this expression in plants. This project will research a special group of plants that exhibit separate males and females – those for which the environment controls the expression of male or female function. Chromosomes that determine male or female flower types are rare in plants and species where the environment plays a strong role have the ability to express either male or female flowers, and change from one to the other, during their lives. Changes in gene expression is the most likely mechanism controlling this phenotype in these species thus, this study examines the relationship between gene expression and floral development in maples and makes comparisons to other plant species with different plant mating systems. Understanding more about how gene expression relates to expression of male versus female flowers will help make more economical decisions and plan for population stability in the face of climate change. This project also involves the development of Course-based Undergraduate Research Experiences that include both field elements and training in modern genetic techniques and analysis. It also involves local outreach with a focus on evolutionary biology.Historically several mechanisms that determine male versus female function in organisms has been categorized: genetic, social, temperature dependent, and environmental. This division has resulted in primarily ecologically-based research of species with suspected environmental determination and reinforced a false dichotomy between genetics and environment. This project investigates the transcriptomic underpinnings of environmentally-based plasticity in floral function and seeks answers to the following questions. 1. Are there differences in the amount and kind of gene expression associated with the expression of floral type? 2. To what extent does the transcriptome change during floral development? 3. How similar is the transcriptomic profile of species with this plasticity in comparison to other species? Is it more similar to those exhibiting dioecy or monoecy? Through this work new understanding of how gene activation and activity responds to the environment to shape floral phenotype will obtain. This understanding is becoming more critical with a changing climate. Furthermore, the proposed research addresses long-held questions on the evolution of plant mating systems. Although environmental control of floral phenotype is frequently mentioned as a potential pathway to dioecy, no studies have explored how transcriptomically similar these species are to those with monoecious or dioecious mating systems. This inhibits our understanding of the route to dioecy, a major and repeated evolutionary transition in plants. Similar evolutionary transitions in animals happened too infrequently and too far back in evolutionary time to facilitate experimental investigation, so if we wish to understand how and why females and males originated, our best chance may reside in the study of plants.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.