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.

不同类型的生物体可以以某种方式相互作用，使它们在无法单独生存时能够共同生存。这些相互作用可能对整个生态系统产生重大影响。该项目将测试热带雨林中的白蚁、细菌和真菌是否相互依赖。科学家推测，以木材为食的白蚁分散了木材腐烂真菌的繁殖结构，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，并且细菌在真菌内部得到庇护。由于这种三向相互作用是建立在以木材为食的生物体的基础上的，因此研究结果将增强人们对热带生态系统中如何发生分解或养分循环的了解。此外，该项目强调了关于物种相互作用的知识还有很多，特别是在生物多样性生态系统中。这项研究将调查圭亚那地盾中潜在的三界互利共生。实地观察得出这样的假设：木材腐烂真菌Guyanagaster necrorhiza使用食木白蚁作为其传播媒介。白蚁食用 G. necrorhiza 所带来的好处仍然难以捉摸。最近，人们发现G. necrorhiza子实体中含有一个肠杆菌科群落，这些肠杆菌经常被认为是重要的固氮互利共生体。该项目将测试以下假设：坏死根菌从当地环境中招募这些细菌，作为其传播策略的一部分。最先进的基因测序技术将用于表征 G. necrorhiza 和当地环境底物中的细菌群落，以确定 G. necrorhiza 是否以及从何处招募细菌。如果 G. necorhiza 正在招募特定的细菌，则推测这些细菌可以固定氮，使子实体成为白蚁丰富的氮源。将进行一系列化学测试，以确定 G. necrorhiza 子实体是否富氮，以及这种富集是否是由于它们含有的固氮细菌所致。如果这两个假设都得到支持，结论将是缺氮生物，例如以木材为食的白蚁，以 G. necrorhiza 为食来补充其饮食，并随后传播孢子。通过使用以木材为食的白蚁作为传播剂，G. necrorhiza 可以将孢子传播到其所需的基质——木材上。