Plant identity strongly structures root-associated fungal community in a subtropical diverse forest

Revealing the relationship between plants and root-associated fungi is very important in understanding diversity maintenance and community assembly in ecosystems. However, the community assembly of root-associated fungi of focal plant species along a subtropical plant species diversity level is less documented. Here, we examined root-associated fungal communities associated with five ectomycorrhizal (EM) plant species (Betula luminifera, Castanea henryi, Castanopsis fargesii, C. sclerophylla, and Quercus serrate) in a Chinese subtropical woody plant species diversity (1, 2, 4, 8, 16 and 24 species) experiment, using a paired-end Illumina MiSeq sequencing of the ITS2 region. In total, we detected 1933 root-associated fungal operational taxonomic units (OTUs) at a 97% sequence similarity level. Plant identity had a significant effect on total and saprotrophic fungal OTU richness, but plant species diversity level had a significant effect on saprotrophic and pathogenic fungal OTU richness. The community composition of total, saprotrophic, pathogenic and EM fungi was structured by plant identity and plant species diversity level (except for pathogenic fungi). This study highlights that plant identity has a stronger effect on root-associated fungal community than plant species diversity level in a subtropical diverse forest.

揭示植物与根系共生真菌的关联，对于理解生态系统中的多样性维持与群落构建机制具有重要意义。然而，针对亚热带植物物种多样性梯度下目标植物物种的根系共生真菌群落构建过程的研究仍较为匮乏。本研究依托中国亚热带木本植物物种多样性实验平台（设置1、2、4、8、16及24个物种的梯度处理），采用ITS2区域的双端Illumina MiSeq测序技术，对5种外生菌根（ectomycorrhizal, EM）植物（Betula luminifera、Castanea henryi、Castanopsis fargesii、C. sclerophylla及Quercus serrate）的根系共生真菌群落展开了调查。本研究共在97%序列相似性阈值下，检测到1933个根系共生真菌操作分类单元（operational taxonomic units, OTU）。宿主植物种类对总真菌及腐生真菌的OTU丰富度具有显著影响；而植物物种多样性梯度则显著影响腐生真菌与病原真菌的OTU丰富度。总真菌、腐生真菌、病原真菌及外生菌根真菌的群落组成均受宿主植物种类与植物物种多样性梯度的调控（病原真菌除外）。本研究表明，在亚热带多物种森林中，宿主植物种类对根系共生真菌群落的影响强于植物物种多样性梯度。