Collaborative Research: RUI: how landscape fragmentation interferes with plant-pathogen interactions that maintain local plant diversity

合作研究：RUI：景观破碎化如何干扰维持当地植物多样性的植物-病原体相互作用

• 批准号: 1655972
• 负责人: Cathy Collins
• 金额: $ 37.17万
• 依托单位: Bard College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1655972&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; how; landscape

Many natural areas are being broken up into smaller fragments due to land-use changes such as suburban sprawl. Compared with larger fragments, small fragments are often extreme environments because they can experience stresses like higher temperatures, more light, and lower soil moisture. This research looks at how plants living in different sized fragments are affected by their pathogens. Interactions between plants and their pathogens are important because although pathogens are best known for the damage they cause they can also help preserve biological diversity. This is because each plant species has its own unique group of pathogens that specialize on it, and slows growth or kills just the plants they infect. This can keep any single plant species from dominating in an area. However, not all pathogens can thrive in the extreme environments found in small patches. It may be that in small patches, different types of pathogens that slow growth or kill multiple plant species indiscriminately are more common. If this is the case, they could decrease plant diversity compared with large patches. By uncovering how plants and pathogens interact in different patch sizes this work will be relevant for understanding the biodiversity consequences of breaking up natural areas, and may affect management of natural landscapes. Both lead researchers for this project are early-career faculty at undergraduate colleges, and will incorporate undergraduate students into all aspects of this work, including community outreach.Three parallel studies will be conducted to assess how plant-pathogen interactions are altered by landscape fragmentation, focusing on fungal pathogens in particular. First, researchers will bury seeds of twelve plant species in patches of different sizes at the Kansas Fragmentation Site, allowing the seeds to be colonized by potential pathogens and testing to see if the seeds remain viable after a year of burial. This will determine if seed mortality due to fungal pathogens is most influenced by ecological factors that vary with patch size, such as plant host density, plant species richness, and microclimatic conditions (such as temperature and soil moisture). Second, the fungal community from these buried seeds will be characterized using both culture-based methods and culture-independent molecular tools. This will determine whether fungal community structure varies predictably with patch size, host identity, and host density. Finally, a combination of greenhouse and field experiments will test the hypothesis that negative feedbacks (when plants "culture" host-specific pathogens in the soil surrounding their roots) are strongest in the interiors of large patches, rather than on the edges of large patches or in small patches. It is predicted that thermally stressful environments on edges and small patches will favor generalist fungi, reducing the influence of diversity-maintaining feedbacks on smaller fragments. Collectively, these studies link individual plant-fungal interactions to observed landscape patterns in plant diversity.

由于土地利用的变化，例如郊区的扩张，许多自然区域被分割成更小的碎片。与较大的碎片相比，较小的碎片往往是极端的环境，因为它们可以经历高温、强光和较低的土壤湿度等压力。这项研究着眼于生活在不同大小碎片中的植物是如何受到病原体的影响的。植物与其病原体之间的相互作用很重要，因为尽管病原体以其造成的损害而闻名，但它们也有助于保护生物多样性。这是因为每种植物都有自己独特的病原体群，它们专门针对自己，减缓生长或杀死被它们感染的植物。这可以防止任何一种植物在一个地区占据主导地位。然而，并不是所有的病原体都能在小块的极端环境中茁壮成长。可能是在小块土地上，不同类型的病原体更常见，它们会减缓生长或不分青红皂白地杀死多种植物。如果是这样的话，与大的斑块相比，它们可能会减少植物多样性。通过揭示植物和病原体如何在不同斑块大小中相互作用，这项工作将有助于理解破坏自然区域对生物多样性的影响，并可能影响自然景观的管理。该项目的两位首席研究员都是本科院校的早期职业教师，他们将把本科生纳入这项工作的各个方面，包括社区外展。将进行三项平行研究，以评估景观破碎化如何改变植物与病原体的相互作用，特别是真菌病原体。首先，研究人员将把12种植物的种子埋在堪萨斯碎片遗址不同大小的斑块上，允许种子被潜在的病原体定植，并测试种子在掩埋一年后是否仍能存活。这将决定真菌病原体导致的种子死亡是否最受随斑块大小而变化的生态因素的影响，如植物寄主密度、植物物种丰富度和小气候条件（如温度和土壤湿度）。其次，将使用基于培养的方法和不依赖于培养的分子工具对这些埋藏种子中的真菌群落进行表征。这将决定真菌群落结构是否随斑块大小、寄主身份和寄主密度而发生可预测的变化。最后，温室和田间实验的结合将检验这样一种假设，即负反馈（当植物在其根周围的土壤中“培养”宿主特异性病原体时）在大斑块的内部最强，而不是在大斑块的边缘或小斑块上。预测边缘和小斑块的热应激环境有利于多面手真菌，减少了多样性维持反馈对小片段的影响。总的来说，这些研究将单个植物-真菌相互作用与植物多样性中观察到的景观模式联系起来。