南亚热带森林木本植物-根系真菌网络模块的构建机制

植物-根系真菌互作构建了具有不同模块性的复杂网络。模块结构不仅能促进物种共存且有利于维持群落稳定性。然而植物-根系真菌网络模块的形成机制仍是悬而未决的问题。以往研究发现相比于土壤环境和空间分布，植物比叶面积与植物-根系真菌网络模块组成明显相关。然而，相比于叶性状，根性状（尤其是次生代谢物）是植物-根系真菌建立特异性关联的直接因素。我们前期的研究发现物种多度和空间不能预测网络模块性，而部分根系形态结构与模块组成明显相关。据此我们提出假设：根系性状及植物-真菌谱系关联的生态位过程是形成植物-根系真菌网络模块的主要驱动力。我们拟在该样地采集80个物种共960株植物的根样品，通过高通量测序构建植物-根系真菌网络。我们利用统计模型比较多度、空间、根性状（根化学元素、次生代谢物和根形态结构）和谱系对形成网络模块的相对贡献，阐明驱动模块构建的关键根性状，揭示根系系统调控的生态位过程是形成模块的驱动力。

Plants and root-associated fungi interact to form complicated network with different modularity. Network modularity not only can maintain species coexistence but also enhance community stability. Nevertheless, we have failed to understand the underlying mechanisms responsible for such modular structure of plant-fungus association network. Previous studies show that compared to soil environment and spatial distribution, specific leaf area of host plant is significantly related to module composition. However, compared to leaf traits, root traits (in particular plant secondary metabolites) directly regulates the formation of specific associations of plant and root fungus. Our preliminary study shows that species abundance and spatial information could not well predict the modularity of plant-root fungal association network in a forest plot, but some root morphological traits significantly associated with module species composition. Thus, we hypothesize that niche processes associated with root traits and plant-fungus phylogeny are major driving forces in shaping modular structure of plant-root fungus association networks. In this project, we will investigate root samples of 960 trees from 80 species in the forest plot and construct plant-root fungal association network via the DNA metabarcoding sequencing technology. We will quantify the relative contribution of root morphological structures, stoichiometric traits, secondary metabolites and phylogenies of plants and fungi on shaping the modular structure of plant-root fungus association networks, and illustrate the key root traits driving modular structure. This project will reveal that niche processes regulated by root system are major drivers of modular structure of plant-root fungus association networks.