3种红树植物根际与非根际土壤细菌群落结构及多样性特征

Microbial Community Structure and Diversity in Rhizosphere and Non-rhizosphere Soils at Fields of Three Varieties of Mangrove Plants

【目的】研究秋茄、白骨壤、桐花树等3种红树植物根际与非根际土壤细菌群落结构及多样性特征,为阐明土壤微生物群落对红树植物的生长及其在红树林生态系统保护与修复中的重要作用提供科学支撑。【方法】提取3种红树植物根际土壤及同一区域非根际土壤宏基因组DNA,利用Illumina NovaSeq测序技术,分析土壤细菌群落结构及多样性。【结果】(1)4组土壤样本共鉴定出细菌39门、55纲、126目、244科、511属,非根际土壤样本OTU数目大于3组红树植物土壤样本,同时其在观测物种数和多样性指数上也表现出了更高的丰富性与多样性;(2)4组土壤样本中变形菌门的相对丰度均大于60%,占据绝对主导地位。4组土壤样本之间相比较,秋茄根际土壤样本中厚壁菌门和梭杆菌门有更高的丰度,桐花树根际土壤样本里变形菌门的丰度有一定优势,白骨壤根际土壤样本里拟杆菌门的丰度高于其他3组。非根际土壤样本里的芽单胞菌门略微占有优势,但是其在拟杆菌门的丰度却低于3组根际土壤样本;(3)PCA分析发现桐花树与白骨壤根际土壤的群落组成较为接近,4组样本的根际细菌群落对应的COG类目大致相同。【结论】红树植物非根际土壤的细菌群落有更高的多样性,不同红树植物的重要作用类群不同。

【Objective】Structure and diversity of the microbial communities in the rhizosphere and non-rhizosphere soils on lots grown with different mangrove plants were studied for improved protection and restoration of the ecosystem.【Methods】Metagenomic DNAs were extracted from the rhizosphere and field soils on Kandelia obovata,Avicennia marina,Aegiceras corniculatum lots and the field soil at an open lot for Illumina NovaSeq sequencing to determine the microbial community structure and diversity.【Results】(1)A total of 39 phyla,55 classes,126 orders,244 families,and 511 genera of microbes were identified in the soils.There were more OTUs in the non-rhizosphere field soils,as well as higher number of species and diversity index,than in the rhizosphere soils.(2)In the 4 field soils,the greater than 60%relative abundances of Proteobacteria were significantly dominant in the communities.Firmicutes and Fusobacterium were more abundant on the lot at K.obovate field;Proteobacteria at A.corniculatum field;and Bacteroidetes at A.marina field.At phylum level,Bacillus was slightly more in the field soils,but Bacteroidetes less,than in their rhizosphere counterparts.(3)The PCA analysis indicated the microbial compositions of the rhizosphere soils at the A.corniculatum and A.marina fields to be similar,and the corresponding COG categories of communities in rhizosphere soils roughly the same.【Conclusion】The microbial communities in the nonrhizosphere field soils were more diverse than in the rhizosphere soils at the lots of various mangrove plants.The major functional microbes in the communities differed by the mangrove variety that grew on the soil.