Dissertation Research: Disentangling a Potential Tri-Kingdom Mutualism in the Guiana Shield

论文研究：解开圭亚那地盾中潜在的三国互惠关系

• 批准号: 1501782
• 负责人: Mary Aime
• 金额: $ 2.01万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1501782&HistoricalAwards=false
• 关键词: Dissertation; Research; Disentangling; Potential; Tri

Very different types of organisms can interact in ways that allow them to survive together when they would be unable to survive alone. These interactions can have major impacts on entire ecosystems. This project will test whether termites, bacteria, and a fungus depend on each other in a tropical rainforest. Scientists hypothesize that wood-feeding termites disperse the reproductive structures of a wood-decaying fungus so it can colonize new substrates, that the fungus houses bacteria beneficial to termites, and that the bacteria receive shelter inside the fungus. Because this three-way interaction is built on wood-feeding organisms, results of the study will augment knowledge of how decomposition, or nutrient recycling, occurs in tropical ecosystems. Additionally, this project underscores how much remains to be learned about species interactions, especially in biodiverse ecosystems.This study will investigate a potential tri-kingdom mutualism in the Guiana Shield. Field observations have led to the hypothesis that a wood-decay fungus, Guyanagaster necrorhiza, uses wood-feeding termites as its dispersal agent. Benefits to the termites for consuming G. necrorhiza remain elusive. Recently, it was discovered G. necrorhiza fruiting bodies harbor a community of Enterobacteriaceae, which are frequently identified as important nitrogen-fixing mutualists. This project will test the hypothesis that G. necrorhiza recruits these bacteria from its local environment as part of its dispersal strategy. State-of-the-art genetic sequencing technology will be used to characterize the bacterial communities in G. necrorhiza and substrates of the local environment to determine if and from where G. necrorhiza is recruiting bacteria. If G. necorhiza is recruiting specific bacteria, it is hypothesized that these bacteria fix nitrogen, making the fruiting bodies a rich source of nitrogen for termites. A series of chemical tests will be performed to determine if G. necrorhiza fruiting bodies are nitrogen-enriched, and if this enrichment is due to nitrogen-fixing bacteria that they harbor. If both hypotheses are supported, the conclusion will be that nitrogen-starved organisms, such as wood-feeding termites, feed on G. necrorhiza to supplement their diet and that they subsequently disperse the spores. By using wood-feeding termites as dispersal agents, G. necrorhiza accomplishes spore dispersal targeted to its desired substrate, wood.

非常不同类型的生物体可以相互作用，使它们能够在无法单独生存的情况下共同生存。这些相互作用可能对整个生态系统产生重大影响。该项目将测试白蚁、细菌和真菌在热带雨林中是否相互依赖。科学家们假设，以木材为食的白蚁分散了木材腐烂真菌的生殖结构，因此它可以在新的基质上定居，真菌中含有对白蚁有益的细菌，并且细菌在真菌中得到庇护。由于这种三向相互作用是建立在食木生物上的，因此研究结果将增加对热带生态系统中分解或营养循环如何发生的了解。此外，该项目强调了物种之间的相互作用，特别是在生物多样性生态系统中，还有多少有待了解。实地观察导致了一种假设，即木材腐烂真菌，Guyanagaster necrorhiza，使用木材喂养的白蚁作为其传播媒介。对白蚁食用G.腐烂根仍然难以捉摸。近年来，G.黑根子实体中含有肠杆菌科细菌，这些细菌通常被认为是重要的固氮互惠菌。本项目将检验G.根癌菌从当地环境中招募这些细菌，作为其传播策略的一部分。最新的基因测序技术将被用来表征G。和当地环境的基板，以确定是否和从哪里G。坏死根正在吸收细菌。如果G. necorhiza正在招募特定的细菌，假设这些细菌固定氮，使子实体成为白蚁丰富的氮源。将进行一系列的化学测试，以确定是否G。黑根子实体是富氮的，如果这种富集是由于它们所携带的固氮细菌。如果这两种假设都得到支持，那么结论就是氮饥饿的生物，如食木白蚁，以G。它们通过食用根腐菌来补充食物，然后传播孢子。以食木白蚁为扩散媒介，研究了G. Necrorhiza完成孢子传播，目标是其所需的基板，木材。