MIM: Microbial Division of Labor in Polysaccharide-Degrading Communities

微生物生态系统被称为“微生物组”，在地球上的所有环境中定居。微生物组在重要的环境过程中起着至关重要的作用，如营养循环和抗逆。在这些生态系统中，微生物激烈竞争易于消费的简单食物，如糖，这些食物被迅速消耗。因此，自然界中的微生物群落通常以多糖等更复杂的食物来源生存。在争夺一个简单糖分子的竞争中，一种微生物将最终获胜，失败者将灭绝。与单糖不同，多糖由于其复杂的结构，通常需要许多不同的酶才能完全降解。这为微生物提供了机会，使其能够将降解的劳动力在它们之间进行分配，每个微生物专门从事几项任务。因此，多糖的微生物降解可以允许不同的物种共存。该项目的目标是揭示微生物在降解复杂多糖分子时如何分工的生命规则。为此，将在天然和合成微生物群落中测量每种微生物在多糖降解中所起的作用。将开发一个计算模型，并用于预测成员如何分工。进一步的实验将测试这些模型预测的有效性。这项研究的成功完成将使我们对劳动分工维持微生物多样性的规则有新的认识。这些信息将通过促进微生物生物过程的工程化和控制天然微生物组而具有广泛的益处。此外，该项目将通过提供先进技术的培训来帮助开发下一代微生物组工作人员，以测量和建模微生物行为。社会的进一步利益将来自公众宣传，旨在提高对微生物生态学的认识，并向K-12学生教授微生物生态学概念。本项目的目标是揭示复杂的基质结构如何通过劳动分工（DOL）影响微生物多样性和群落功能的生态规则。该项目测试了多糖底物分子复杂性通过不同的运输策略和交替的基因调控模式维持功能退化的微生物多样性的假设。总之，多样性和基因调控导致优选的多糖结构和降解产物的不同层次。进一步假设这些机制导致成员之间的DOL，其允许降解特定分子结构的微生物的生态位划分，从而使竞争最小化。为实现项目目标，具体的研究目标是：i）确定多糖降解微生物群落的生态位以及对群落生产力和C和N流的总体影响; ii）开发多糖降解群落的基因组尺度代谢网络模型，并提出将微生物相互作用分解为基本DOL单元的理论框架;以及iii）确定DOL如何在将多样性与社区生产力和稳定性联系起来方面发挥关键作用。这项研究的成功完成将揭示微生物在消耗复杂底物的社区中分工的机制，并将这种机制知识转化为理论，描述微生物DOL相互作用如何保持多样性并影响新兴特性。更广泛的社会效益来自于推进微生物联合体工程的合成生态学策略，其应用于从修复、生物加工和生态系统科学等不同领域。通过基于项目的课程开发、公共宣传、培训研讨会和为K-12受众开发教学工具，帮助建立微生物组劳动力的努力带来了额外的好处。该项目由数学和物理科学理事会的CHE生命过程化学项目和工程理事会的CBET环境工程项目共同资助。该奖项反映了NSF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。

Microbial ecosystems called ‘microbiomes’ colonize all environments on Earth. Microbiomes play crucial roles in important environmental processes such as nutrient cycling and stress resistance. In these ecosystems, microbes compete strongly for easy-to-consume simple foods like sugars, which are rapidly consumed. Therefore, microbial communities in nature typically survive on more complex food sources like polysaccharides. In competition for a simple sugar molecule, one microbe will eventually win and the losers will go extinct. In contrast to simple sugars, polysaccharides typically require many different enzymes for complete degradation because of their complex structure. This provides opportunity for microbes to divide the labor of degradation amongst themselves with each microorganism specializing in a few tasks. Thus, microbial degradation of polysaccharides can allow diverse species to coexist. The goal of this project is to uncover the rules of life that govern how microbes divide labor when degrading complex polysaccharide molecules. To do so, the role each microorganism plays in polysaccharide degradation will be measured in natural and synthetic microbial communities. A computational model will be developed and used to predict how members divide labor. Further experiments will test these model predictions for validation. Successful completion of this research will yield new understanding of the rules by which division of labor sustains microbial diversity. Such information will have broad benefits by facilitating the engineering of microbial bioprocesses and controlling natural microbiomes. In addition, this project will help develop the next generation microbiome workforce by providing training in advanced techniques for measurement and modeling of microbial behavior. Further benefits to society will arise from public outreach designed to boost awareness of microbial ecology and teach microbial ecology concepts to K-12 students. The goal of this project is to uncover the ecological rules governing how complex substrate structure influences microbial diversity and community function through division of labor (DOL). This project tests the hypothesis that polysaccharide substrate molecular complexity sustains functionally degenerate microbial diversity through diverse transport strategies and alternate gene regulatory patterns. Together, diversity and gene regulation result in distinct hierarchies of preferred polysaccharide structures and degradation products. These mechanisms are further hypothesized to result in DOL among members that allows niche partitioning of microorganisms that degrade specific molecular structures, thereby minimizing competition. Specific research objectives to achieve the project goals are to: i) define the niches of polysaccharide-degrading microbial communities and the overall impact on community productivity and C and N flow; ii) develop genome-scale metabolic network models of polysaccharide-degrading communities and propose a theoretical framework that decomposes microbial interactions into basic DOL units; and iii) determine how DOL plays a key role in linking diversity to community productivity and stability. Successful completion of this research will uncover mechanisms by which microbes divide labor in communities consuming complex substrates and translate that mechanistic knowledge into theory that describes how microbial DOL interactions maintain diversity and influence emergent properties. Broader benefits to society result from advancing synthetic ecology strategies for the engineering of microbial consortia with applications in diverse fields ranging from remediation, bioprocessing, and ecosystem sciences. Additional benefits result from efforts to help build a microbiome workforce via project-based course development, public outreach, training workshops, and development of instructional tools for K-12 audiences. This project is supported by co-funding from the CHE Chemistry of Life Processes program in the Math and Physical Sciences Directorate and the CBET Environmental Engineering program in the Engineering Directorate.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.