Saadani Mariem, Hönig Lydia, Bien Steffen, Koehler Michael, Rutten Gemma, Wubet Tesfaye, Braun Uwe, Bruelheide Helge
Institute of Biology/Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Am Kirchtor 1, 06108 Halle, Germany.
German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstr. 4, 04103 Leipzig, Germany.
J Fungi (Basel). 2021 Feb 27;7(3):173. doi: 10.3390/jof7030173.
Leaf fungal pathogens alter their host species' performance and, thus, changes in fungal species composition can translate into effects at the tree community scale. Conversely, the functional diversity of tree species in a host tree's local neighbourhood can affect the host's foliar fungal infestation. Therefore, understanding the factors that affect fungal infestations is important to advance our understanding of biodiversity-ecosystem functioning (BEF) relationships. Here we make use of the largest BEF tree experiment worldwide, the BEF-China experiment, where we selected tree host species with different neighbour species. Identifying fungal taxa by microscopy and by high-throughput DNA sequencing techniques based on the internal transcribed spacer (ITS) rDNA region, we analysed the fungal richness and infestation rates of our target trees as a function of local species richness. Based on the visual microscopic assessment, we found that a higher tree diversity reduced fungal richness and host-specific fungal infestation in the host's local neighbourhood, while molecular fungal richness was unaffected. This diversity effect was mainly explained by the decrease in host proportion. Thus, the dilution of host species in the local neighbourhood was the primary mechanism in reducing the fungal disease severity. Overall, our study suggests that diverse forests will suffer less from foliar fungal diseases compared to those with lower diversity.
叶片真菌病原体改变其寄主物种的表现，因此，真菌物种组成的变化可转化为对树木群落尺度的影响。相反，寄主树当地邻域内树种的功能多样性会影响寄主的叶片真菌感染情况。因此，了解影响真菌感染的因素对于推进我们对生物多样性与生态系统功能（BEF）关系的理解很重要。在此，我们利用了全球最大的BEF树木实验——中国BEF实验，在该实验中我们选择了具有不同邻域物种的树木寄主物种。通过显微镜检查以及基于内转录间隔区（ITS）核糖体DNA区域的高通量DNA测序技术来鉴定真菌分类群，我们分析了目标树的真菌丰富度和感染率作为当地物种丰富度的函数。基于直观的显微镜评估，我们发现较高的树木多样性降低了寄主当地邻域内的真菌丰富度和寄主特异性真菌感染，而分子真菌丰富度未受影响。这种多样性效应主要由寄主比例的降低来解释。因此，当地邻域内寄主物种的稀释是降低真菌病害严重程度 的主要机制。总体而言，我们的研究表明，与多样性较低的森林相比，多样化的森林遭受叶片真菌病害的程度更低。
