Dimensions: Collaborative Research: Assembly and function of nectar microbial communities

这个项目的目标是研究生活在花蜜中的微生物（小到不容易看到的生命，如酵母和细菌）的生态学。对于这些生物来说，花蜜是一个有趣的地方，因为花蜜持续的时间不长——大多数花只持续几天。然而，每一朵花都可能是一个复杂而不断变化的酵母和细菌“群落”的家园；它们是微型生态系统。科学家们将进行实验，探索这些微生物是如何进入花蜜的，以及它们到达花蜜的顺序是否决定了最终生活在花蜜中的微生物。因为每种花都有自己独立的生态系统，科学家可以很容易地对其进行调整，所以这个研究系统对于理解各种规模的生态系统是如何发展的很好。在试图帮助保护稀有物种和保持生态系统以有利于人类和野生动物的方式运作时，这种理解是很重要的。例如，在这个项目中，最终进入花朵的特定酵母菌群和细菌可能会对授粉者访问花朵的方式产生重大影响，从而影响花朵授粉的效率。考虑到人类吃的很多东西都依赖于农作物的授粉，了解什么能导致更有效的授粉具有经济和社会意义。高中生将在为期7周的暑期研究实习中接受研究指导。研究生和博士后将帮助指导这些高中生，他们自己也会受到指导。将举办生物信息学讲习班，训练学生掌握数据分析的基本技能。将对加州一种蜂鸟授粉灌木的花蜜微生物进行实地观察、实地实验和实验室实验的结合。通过构建植物-蜂鸟-花蜜微生物相互作用模拟模型，整合数据，为群落组装理论提供检验。研究人员将整合生物多样性的遗传、系统发育和功能维度，研究：(1)酵母遗传多样性和细菌系统发育多样性如何受到开花物候的影响；(2)酵母遗传多样性和细菌系统发育多样性如何通过花蜜内的拮抗优先效应相互抑制；(3)酵母遗传多样性和细菌系统发育多样性通过改变花蜜中的花蜜化学来改变蜂鸟的觅食偏好，从而影响花在花蜜化学、授粉成功和种子生产方面的功能多样性；(4)花的功能多样性如何通过改变酵母和细菌在花中的传播来反馈影响酵母遗传多样性和细菌系统发育多样性。

The goal of this project is to study the ecology of micro-organisms (life too small to be easily seen, like yeast and bacteria) that live in the nectar of flowers. Nectar is an interesting place for such organisms to live because it doesn't last long -- most flowers last only a few days. Yet, each flower can be home to a complex and changing "community" of yeast and bacteria; they are miniature ecosystems. Scientists will conduct experiments to explore how those micro-organisms get into nectar and whether the order in which they arrive determines the final set that end up living there. Because each flower contains its own separate ecosystem that can be easily tweaked by scientists, this study system is a good one for understanding how ecosystems of all sizes may develop. Such understanding is important when trying to help preserve rare species and to keep ecosystems functioning in ways that benefit both humans and wildlife. In this project, for example, the particular set of yeast and bacteria that end up in flowers may have a large impact on what pollinators visit flowers and thus on how effectively the flowers are pollinated. Given that a lot of what humans eat depends on pollination of crops, understanding what can lead to more effective pollination has both economic and social relevance. High-school students will be mentored in research through a 7-week summer research internship. Graduate students and postdoctoral fellows will help mentor those high school students and be mentored, themselves. Workshops on bioinformatics will be offered to train students in essential skills of data analysis.A combination of field observations, field experiments, and laboratory experiments will be conducted on nectar microbes associated with a hummingbird-pollinated shrub in California. Data will be integrated through construction of a simulation model of plant-hummingbird-nectar microbe interactions, providing tests of community assembly theory. Researchers will integrate genetic, phylogenetic and functional dimensions of biodiversity by studying how (1) yeast genetic diversity and bacterial phylogenetic diversity are influenced by flowering phenology, (2) yeast genetic diversity and bacterial phylogenetic diversity suppress each other through antagonistic priority effects within floral nectar, (3) yeast genetic diversity and bacterial phylogenetic diversity alter hummingbirds' foraging preference by modifying nectar chemistry as a result of growth in nectar, thereby affecting functional diversity of flowers in terms of nectar chemistry, pollination success, and seed production, and (4) how functional diversity of flowers feeds back to affect yeast genetic diversity and bacterial phylogenetic diversity via altered dispersal of yeast and bacteria across flowers.