Collaborative Research: Microbial necromass decomposition: moving from predictions to principles

合作研究：微生物坏死物分解：从预测到原理

• 批准号: 2038304
• 负责人: Jeffrey Gardner
• 金额: $ 46.27万
• 依托单位: University of Maryland Baltimore County
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2038304&HistoricalAwards=false
• 关键词: Collaborative; Research; Microbial; necromass; decomposition

Microorganisms have been increasingly recognized as significant contributors to the accumulation of organic matter in soil through the inputs of their own dead cell material, collectively referred to as necromass. Despite progress in quantifying the ecological factors affecting the rates of necromass decomposition, which microorganisms actually drive this turnover and how interactions among different functional groups affect degradation dynamics remains poorly understood. The overarching objective of the proposed research is to functionally characterize how bacteria and fungi, both alone and together, degrade microbial necromass and how the carbon and nitrogen from necromass moves into different ecosystem pools (both soils and plants). The cross-disciplinary strengths of the research team will provide a holistic understanding of how decomposer community functioning influences microbial necromass decomposition in ways directly relevant to important ecosystem services such as soil carbon storage and plant nutrient acquisition. Along with enhancing our understanding of the functioning of necromass-associated microbial communities, the project has multiple broader impacts activities focused on sharing knowledge with public audiences and training a diverse pool of STEM-focused students. The specific research aims include: Aim 1: Characterize the genes and metabolic pathways involved in microbial necromass degradation using well-studied fungal and bacterial decomposition systems; Aim 2: Determine which soil microbes use resources derived from microbial necromass and how its decomposition affects soil carbon and nitrogen pools; Aim 3: Track how trees acquire microbial necromass-derived nitrogen via ectomycorrhizal fungal symbioses. These aims will be addressed through an integrated set of experiments that scale from individual microbial cultures to complex communities. In the first aim, RNAseq-based lab experiments will generate a detailed profile of gene expression during the decay of fungal necromass in an ecologically relevant and diverse set of fungi and bacteria. The second aim will couple qSIP analyses of the microbial communities on field-based decaying necromass with isotopic analyses of surrounding soils and roots (using both IRMS and NanoSIMS imaging) to quantitatively track carbon and nitrogen release from necromass types into different ecosystem pools. Finally, in Aim 3, microbial communities present on lab-incubated necromass will be experimentally manipulated to examine how initial substrate chemistry and interspecific competition affect the amount of necromass nitrogen transferred to trees by ectomycorrhizal fungi. Collectively, this research seeks to transition the study microbial necromass decomposition from a largely descriptive to a mechanistically predictive science.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.

微生物越来越被认为是土壤中有机质积累的重要贡献者，它们通过输入自己的死亡细胞物质，统称为坏死体。尽管在量化影响尸块分解速度的生态因素方面取得了进展，但哪些微生物实际上推动了这种周转，以及不同官能团之间的相互作用如何影响降解动力学，仍然知之甚少。拟议研究的首要目标是从功能上描述细菌和真菌如何单独和共同降解微生物坏死体，以及死亡体中的碳和氮如何进入不同的生态系统池(土壤和植物)。研究团队的跨学科优势将提供对分解者群落功能如何影响微生物坏死体分解的整体理解，这些影响与土壤碳储存和植物养分获取等重要生态系统服务直接相关。除了加强我们对尸块相关微生物群落功能的了解外，该项目还具有多项更广泛的影响活动，重点是与公众分享知识和培训不同的STEM学生群体。具体研究目标包括：目标1：利用研究充分的真菌和细菌分解系统确定参与微生物坏死体降解的基因和代谢途径；目标2：确定哪些土壤微生物利用微生物坏死体来源的资源及其分解如何影响土壤碳库和氮库；目标3：追踪树木如何通过外生菌根真菌共生获得微生物坏死体来源的氮。这些目标将通过从单个微生物培养到复杂群落的一系列综合实验来实现。在第一个目标中，基于RNAseq的实验室实验将在一组具有生态相关性和多样性的真菌和细菌中产生真菌坏死团腐烂过程中基因表达的详细概况。第二个目标是将现场腐烂坏死体上微生物群落的qSIP分析与周围土壤和根部的同位素分析(使用IRMS和NanoSIMS成像)结合起来，以定量跟踪从坏死体类型向不同生态系统池释放的碳和氮。最后，在目标3中，将对实验室培养的坏死体上的微生物群落进行实验操作，以检查初始底物化学和种间竞争如何影响外生菌根真菌向树木转移的坏死体氮量。总而言之，这项研究试图将微生物坏死瘤分解的研究从主要的描述性科学转变为机械预测性科学。这一奖项反映了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。