Research Starter Grant: Metabolic Pathways in Bacterial Utilization of Hemicellulosic Sugars

作为地球上碳循环的一部分，植物将二氧化碳以有机碳的形式储存在它们的生物量中，这些有机碳随后可以通过微生物对植物碎屑的降解以二氧化碳的形式呼吸回大气中。据估计，植物生物量的天然微生物呼吸作用产生的二氧化碳输入量是人类活动的8至10倍。以前的实地观察表明，植物物质的分解依赖于植被覆盖的类型，温度的升高可导致分解速率的增加。因此，对控制不同植物物质组分分解速率的生物因素有一个基本的了解是非常重要的。然而，负责植物物质组分呼吸的生物学途径尚不清楚。本研究要解决的工作假设是，植物物质的分解速率与植物物质中不同有机成分的分解代谢途径密切相关。以恶臭假单胞菌为模型好氧细菌，研究半纤维素糖的代谢途径。这项研究的结果将有助于我们理解植物物质代谢的生化动力学，这是准确预测全球碳循环对气候变化反馈响应的必要前提。更广泛的影响该项目将涉及青年科学家的培训和参与，以从根本上解决全球环境问题。鉴于这项具有环境影响的研究的全球重要性，所获得的结果将引起各种生物和化学学科的科学家以及整个社会的兴趣，并将在广泛传播的期刊上发表。

Intellectual MeritAs part of the cycle of carbon on earth, plants store carbon dioxide into their biomass as organic carbon, which can be subsequently respired back into the atmosphere as carbon dioxide via microbial degradation of plant detritus. Natural microbial respiration of plant biomass is estimated to contribute eight to ten times greater carbon dioxide inputs than human activities. Previous field observations have indicated a dependence of decomposition of plant matter on the type of vegetation cover and that an increase in temperatures can lead to increased decomposition rates. Thus, of important interest is a fundamental understanding of the biological factors controlling the decomposition rates of different plant matter components. However, the biological pathways responsible for the respiration of plant matter components are not well understood. The working hypothesis to be addressed by this research is that the decomposition rates of plant matter are tightly linked to the pathways underlying the catabolism of the different organic moieties in plant matter. Using Pseudomona putida as a model aerobic bacterial organism, the pathways by which hemicellulosic sugars are metabolized will be investigated. The results from this study will contribute to our understanding of the biochemical dynamics underlying the metabolism of plant matter, a necessary pre-requisite to accurate predictions of the feedback response of the global carbon cycle to climate change. Broader ImpactsThis project will involve the training and participation of young scientists to address global environmental issues at a fundamental level. Given the global importance of this research with environmental implications, the obtained results will be of interest to scientists across various biological and chemical disciplines and to society at-large, and will be published in journals with broad dissemination.