Abstract The quantity and quality of plant-derived resources are the primary factors regulating soil microbial communities, however, the top-down control of soil fauna on the soil food web is still underexplored. To integrate bottom-up and top-down forces in mediating soil microbial communities, we evaluated six plant species rhizosphere microbial community structure (indicated by multiple PLFA biomarkers) and functioning (indicated by four different enzyme activities) in the presence and absence of seven adult Metaphire guillelmi earthworms. Six plant species with two legume species (Trifolium repens and Medicago sativa), two grass species (Arundo donax and Lolium perenne) and two grain crops (Triticum aestivum and Zea mays) were used varying with resource demand and nutrient acquisition strategies. We found earthworms led to increasing in similarity of rhizosphere microbial community structure across all studied plant species. For example, the variability of the fungi: bacteria and gram-positive: gram-negative ratios across six plant species was reduced in the presence of earthworms. Furthermore, earthworms generally supported enzyme production in acquiring carbon over nitrogen and phosphorus, and enhanced immobilization sink for N in microbial biomass, suggesting earthworms are more beneficial for microbes in acquiring energy as plant roots-produced enzyme mostly targeted on nutrients. In conclusion, our results revealed a context-dependent earthworm effects on microbial community structure and a general pattern of earthworms in shifting enzyme production across different plant species.

中文翻译：

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食地蚯蚓Metaphire guillelmi对根际微生物群落结构和功能的影响因植物种类而异

摘要 植物源性资源的数量和质量是调控土壤微生物群落的主要因素，但自上而下地调控土壤食物网中的土壤动物群落尚缺乏探索。为了整合介导土壤微生物群落的自下而上和自上而下的力量，我们评估了六种植物根际微生物群落结构（由多种 PLFA 生物标志物表示）和功能（由四种不同的酶活性表示）在存在和不存在 7 个成虫的情况下Metaphire guillelmi 蚯蚓。使用六种植物，包括两种豆科植物（白三叶和苜蓿）、两种草类（Arundo donax 和 Lolium perenne）和两种谷物作物（Triticum aestivum 和 Zea mays），根据资源需求和养分获取策略而有所不同。我们发现蚯蚓导致所有研究植物物种的根际微生物群落结构的相似性增加。例如，在蚯蚓存在的情况下，六种植物物种的真菌：细菌和革兰氏阳性：革兰氏阴性比率的变异性降低。此外，蚯蚓通常支持酶生产以获取碳而不是氮和磷，并增强微生物生物量中 N 的固定汇，这表明蚯蚓更有利于微生物获取能量，因为植物根系产生的酶主要针对养分。总之，我们的结果揭示了环境依赖的蚯蚓对微生物群落结构的影响，以及蚯蚓在不同植物物种间转移酶生产的一般模式。