紫茎泽兰叶内生真菌对其他植物的致病潜力及其生态效应研究

In most cases, it is the novel microbial relationship formed in the introduced range to determine the invasiveness of exotic plants other than plant itself. In recent, a hypothesis assumed that exotic plant could increase growth advantage by accumulating local pathogens. Similarly, we predict that exotic plant could increase growth advantage by accumulating local generalist pathogens in leaf endophytic fungi. In this project, our research works will be focused on an invasive plant Eupatorium adenophorum in South-west of China, to ask: (1) Are there some local generalist pathogens inhabiting the leaf of this invasive plant as endophytic fungi? How about the host range, community number and genetic structure of these generalist pathogens? (2) What is their distribution in the soil and air near by which E. adenophorum lives? (3) What is pathogenicity to both native and economically important plant species in this area? (4) What are the ecological effects of these generalists in term of invasiveness of E. adenophorum? The resulting data could provide novel theory not only for exploring invasive mechanism of exotic plants, but also for understanding the relationship between endophytic fungi and plant biodiversity. In addition, from practical view it is also important for ecological risk assessment and restoration for invasive area.

很多情况下，并非植物本身，而是植物同当地微生物形成的新关系决定了外来植物的入侵力。"积累当地病原微生物假说（Accumulation of local pathogens）"认为外来植物能够在入侵地积累当地植物病原菌来获得竞争优势。我们提出的新观点预期：外来植物可以在叶内生真菌中富集本地植物病原菌来间接促进其入侵。基于这一观点，本项目以在我国西南地区广泛入侵的紫茎泽兰为研究对象，结合生态学和微生物学手段，研究：（1）紫茎泽兰叶内生真菌中是否有其他本地植物的病原菌？它们的宿主范围、数量和遗传结构如何？（2）这些病原菌在紫茎泽兰生长环境中的分布情况如何？（3）在当地植物和经济作物中的感染情况如何？（4）对紫茎泽兰入侵的生态学效应是什么？等问题。研究结果将对人们探索外来植物入侵机理、理解植物叶内生真菌的生态学功能等基础科学问题提供新理论、新观点。此外，对植物入侵的生态安全评价也具有重要实践价值。

很多情况下，并非植物本身，而是植物同当地微生物形成的新关系决定了外来植物的入侵力。"积累当地病原微生物假说（Accumulation of local pathogens）"认为外来植物能够在入侵地积累当地植物病原菌来获得竞争优势。我们提出的新观点预期：外来植物可以在叶内生真菌中富集本地植物病原菌来间接促进其入侵。本项目研究结果表明，（1）紫茎泽兰优势叶内生真菌炭疽菌属（Collectotrichum），链格孢菌属（Alternaria），炭角菌属（Xylaria）和间座壳属（Phomopsis）中有很多菌株都具有对本地植物和经济作物叶面致病的潜力，部分菌株还显示了对本地植物种子发芽和生长的不利影响；（2）这些病原菌广泛分布在紫茎泽兰生长环境中，炭疽菌通过空气传播的可能性较大，而链格孢可能通过腐叶传播的机会要高；（3）炭疽菌和链格孢的优势基因型菌株广泛分布在当地植物和经济作物的病斑菌种群中；（4）紫茎泽兰叶内生菌在刺激紫茎泽兰生长的同时，能够对多种测试的本地植物产生不同程度的不利影响。我们推测，叶内生菌可以作为一种隐形的武器，在紫茎泽兰入侵过程中扮演一定的作用。