Root-associated fungi play a vital role in maintaining nutrient absorption and health of host plants. To compare the responses of root-associated fungal community structures to nitrogen (N) and/or phosphorus (P) additions across differential mycorrhizal types, we collected roots of nine plant species belonging to three mycorrhizal types (arbuscular mycorrhiza, ectomycorrhiza, and ericoid mycorrhiza) under control and N and/or P addition treatments from a subtropical forest, and detected the diversity and community composition of fungi inhabiting roots through the high-throughput sequencing technique. The results showed that root-associated fungal communities of all nine plant species were mainly composed of Basidiomycota and Ascomycota. The relative abundance of Ascomycota and Basidiomycota was significantly lower and higher under the P addition than that under control, respectively. The relative abundance of Ascomycota of ericoid mycorrhizal trees was significantly higher than those of arbuscular mycorrhizal and ectomycorrhizal trees, while the relative abundance of Basidiomycota was significantly lower than the other two mycorrhizal types. Compared with the control, P addition significantly reduced the α-diversity and changed community composition of root-associated fungi across different mycorrhizal plant types, while no effect of N addition or mycorrhizal type was observed. Compared with the control and N addition treatments, NP addition caused root-associated fungal communities of all plants becoming integrally divergent. In addition, the fungal communities of ectomycorrhizal mycorrhizal trees became apparently convergent in comparison with those of arbuscular and ericoid mycorrhizal trees under the NP addition. Collectively, our results highlighted that P was a critical factor influencing community structures of tree root-associated fungi in subtropical forest soils. This study would enhance our understanding of the responses and maintenance mechanisms of plant root-associated fungal diversity under global environmental changes in the subtropical region.
植物根系真菌对维系植物的营养吸收和健康具有重要作用。本研究分析了不同菌根类型植物根系中真菌的群落结构对外源氮(N)、磷(P)、氮和磷(NP)输入的响应。试验采集了无添加(对照)和N、P、NP添加处理下亚热带森林3种菌根类型(丛枝菌根、外生菌根、欧石楠菌根)9种植物的根系,运用高通量测序技术检测根系中真菌的多样性和群落组成。结果表明: 9种植物根系真菌群落均主要由担子菌门和子囊菌门组成;P添加下子囊菌门的相对多度显著低于对照,而担子菌门的相对多度显著高于对照。欧石楠菌根植物根系中子囊菌门的相对多度显著高于丛枝菌根和外生菌根植物,而其担子菌门的相对多度显著低于丛枝菌根和外生菌根植物。与对照相比,P添加显著降低了植物根系中真菌的α多样性,改变了不同菌根类型植物根系中真菌的群落组成,而N添加和菌根类型的影响不明显。与对照和N添加相比,NP添加使全部植物根系中真菌群落变异程度更大,即群落整体更加趋异,而外生菌根植物根系中的真菌群落比丛枝菌根植物根系中的真菌群落变异更小,即群落更趋同。综上,P养分是影响亚热带森林土壤中树木根系真菌群落结构的关键因素。本研究有助于提升对全球环境变化下亚热带地区植物根系真菌多样性的响应与维持机制的理解。.
Keywords: community structure; diversity; nitrogen addition; phosphorus addition; root-associated fungi.