Symbiotic ecology: mycobiont-photobiont interactions in tropical lichens along environmental gradients

共生生态​​学：热带地衣中沿着环境梯度的真菌生物体-光生物体相互作用

• 批准号: 408295270
• 负责人: Dr. Ulla Kaasalainen, Ph.D.
• 金额: --
• 依托单位: Abteilung Geobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/408295270?language=en
• 关键词: Symbiotic; ecology; mycobiont; photobiont; interactions

Lichen symbioses are mutualistic associations between mycobionts (fungi) and photobionts (green algae and/or cyanobacteria) in which the photobionts provide carbohydrates and the fungi provide a sheltered environment for their photobionts. During their complex evolutionary history, this highly successful nutritional strategy has evolved to a plethora of different growth forms and habitat ecologies, and lichens can be found in almost all terrestrial ecosystems from the tropics to polar regions. The application of molecular biological methods has revealed previously unexpected levels of genetic diversity especially in many tropical lineages of lichen-symbiotic organisms, and while some groups of macrolichens in boreal and temperate regions are relatively well known, the knowledge about symbiont diversity and association patterns in the tropics is meagre. However, understanding the relevance of the diversity patterns and the ecology of species interactions is fundamental in addressing the challenges of environmental change to lichens. It is the aim of this project to explore how the symbiotic diversity and the complexity of interactions relate to environmental variables and define symbiont ecology. The proposal focuses on lichen symbiont interactions along a steep environmental gradient on the slopes of the tropical Mount Kilimanjaro. The study setting, previously established by the DFG funded Kilimanjaro Research group, includes 60 permanent study plots with known environmental conditions, representing 12 different ecosystems from tropical savanna to alpine heath vegetation. Lichen symbiont diversity sampled both from lichen thalli and from substrate samples on the sample plots is analyzed using molecular biological methods. Species hypotheses are constructed using a DNA barcoding approach. Nonparametric multiplicative regression (NPMR) is used to analyze differences between symbiont communities and association patterns and their correlations with environmental variables. Utilizing the established study design with unique biological material, state-of-the-art molecular methods, and thorough data analysis, I can answer several relevant and timely research questions and test predictions. My specific aims include the following. A) What is the impact of environmental stress on individual symbiont genotypes and symbiotic consortia (lichen species). B) What is the role of symbiotic interactions in determining habitat and substrate ecology. C) How does the predicted facilitative role of photobiont-mediated lichen guilds and the guild-level interactions impact lichen community structure. This project will dramatically improve our current understanding of lichen ecology and biogeography, especially mycobiont-photobiont and mycobiont-mycobiont interactions within lichen symbioses, and represent a new opening in tropical lichenology.

地衣共生体是真菌和光生生物（绿色藻类和/或蓝细菌）之间的互利共生关系，其中光生生物提供碳水化合物，真菌为其光生生物提供庇护环境。在它们复杂的进化历史中，这种非常成功的营养策略已经进化成了大量不同的生长形式和栖息地生态，地衣几乎可以在从热带到极地的所有陆地生态系统中找到。分子生物学方法的应用揭示了以前意想不到的遗传多样性水平，特别是在许多热带谱系的地衣共生生物，而一些群体的macrolichens在北方和温带地区是相对知名的，知识共生体的多样性和协会模式在热带地区是贫乏的。然而，了解多样性模式和物种相互作用的生态学的相关性是解决环境变化对地衣的挑战的基础。这是本项目的目的，探讨共生多样性和相互作用的复杂性与环境变量的关系，并定义共生生态。该提案的重点是地衣共生体的相互作用沿着一个陡峭的环境梯度的热带基利曼哈罗山的斜坡。该研究环境由DFG资助的基利曼哈罗研究小组先前建立，包括60个已知环境条件的永久研究地块，代表了从热带稀树草原到高山石南植被的12种不同生态系统。利用分子生物学方法对地衣共生体多样性进行了分析。使用DNA条形码方法构建物种假设。非参数乘法回归（NPMR）被用来分析共生体群落和关联模式之间的差异及其与环境变量的相关性。利用独特的生物材料，最先进的分子方法和全面的数据分析，我可以回答几个相关和及时的研究问题和测试预测。我的具体目标如下。环境胁迫对个体共生体基因型和共生聚生体（地衣物种）的影响是什么？B）共生相互作用在决定生境和基质生态学中的作用是什么。C）预测的光生物介导的地衣行业协会的促进作用和行业协会水平的相互作用如何影响地衣群落结构。该项目将极大地提高我们目前对地衣生态学和地衣地理学的理解，特别是地衣共生体中的真菌-光合生物和真菌-真菌相互作用，并代表热带地衣学的一个新的开端。