广西凭祥红锥-马尾松混交林菌根际微生物群落结构

以广西凭祥红锥-马尾松混交林中红锥和马尾松为研究对象,采集林下外生菌根和根际土壤,利用高通量测序分析该混交林下的菌根际微生物群落结构。结果表明,红锥、马尾松菌根际优势真菌为红菇属Russula、被孢霉属Mortierella、乳菇属Lactarius、鹅膏属Amanita、拟锁瑚菌属Clavulinopsis、丝盖伞属Inocybe、锁瑚菌属Clavulina和木霉属Trichoderma,其中,Russula为绝对优势类群,菌根和根际中共生真菌均以外生菌根真菌为主。而优势细菌主要为常见菌根辅助细菌,如伯克霍尔德氏菌属Burkholderia、假单细胞菌属Pseudomonas、慢生根瘤菌属Bradyrhizobium、根瘤菌属Rhizobium和土壤杆菌属Agrobacterium,除芽孢杆菌属Bacillus外,菌根内菌根辅助细菌均高于根际。PICRUST功能分析表明红锥和马尾松菌根中部分膜运输通路（ABC transporters、transporters和secretion system ABC）和信号转导通路（two-component system）的丰度高于根际。α多样性分析表明,菌根和根际微生物多样性存在显著差异,马尾松菌根、根际真菌群落多样性显著高于红锥;β多样性分析表明两树种菌根和根际分别具有相似的微生物群落结构。优势菌群和土壤环境因子的RDA分析表明,土壤pH、全磷和全钾是影响菌根际菌群结构的主要环境因子。

Mycorrhizosphere microbial community structure of Castanopsis hystrix and Pinus massoniana mixed plantation in Pingxiang,Guangxi of South China

The mycorrhizosphere microbial community structure in ectomycorrhizae and rhizosphere soil of Castanopsis hystrixandPinus massoniana mixed plantation in Pingxiang, Guangxi was investigated using Illumina MiSeq sequencing. The results showed that the dominant fungi were species of Russula,Mortierella, Lactarius, Amanita, Clavulinopsis, Inocybe, Clavulina and Trichoderma. Among them, Russula was the predominant group. Mycorrhiza helper bacteria Burkholderia, Pseudomonas, Bradyrhizobium,Rhizobiumand Agrobacterium were common. The relative abundance of mycorrhiza helper bacteria in the ectomycorrhizae was significantly higher than that in rhizosphere with the exception of Bacillus. PICRUST analysis showed that membrane transport pathways and signaling molecules and interaction pathways, including ABC transporters, transporters, secretion system and two-component system were more abundant in ectomycorrhizae than in rhizosphere. α diversity analysis showed that there were significant differences between the microbial community diversity of ectomycorrhizae and that of rhizosphere soil. Ectomycorrhizal and rhizosphere fungal community diversity of P.massoniana was significantly higher than that ofC.hystrix. β diversity analysis showed that microbial community structure of ectomycorrhizae and rhizosphere soil of the two tree species was similar. Redundancy analysis between the relative abundance of dominant fungi and bacteria and soil variables showed that soil pH, TP and TK were the main environmental factors affecting the mycorrhizosphere microbial community.