两种盐生植物根际土壤细菌多样性和群落结构

The bacterial diversity and community structures in rhizosphere soil of two halophytes,Lycium ruthenicum and Kalidium capsicum

应用高通量测序技术对西北干旱区两种盐生植物黑果枸杞和里海盐爪爪根际土壤细菌的多样性和群落结构进行研究,旨在揭示两种耐盐植物根际土壤细菌之间以及根际与非根际细菌群落结构间的差异,为深入研究盐生植物根际土壤微生物与耐盐性之间的关系提供理论基础。结果表明:黑果枸杞、里海盐爪爪根际细菌多样性丰度高于非根际土,黑果枸杞根际土壤细菌多样性丰度高于里海盐爪爪。根际和非根际土壤细菌群落的组成和丰度存在差异,从黑果枸杞和里海盐爪爪根际土壤中分别检测出细菌21门289属和22门304属,而从非根际土壤中分别检测出28门285属和24门336属;在两种盐生植物根际土壤中,变形菌门和厚壁菌门均为优势门;拟杆菌门、放线菌门、蓝细菌门及浮霉菌门在根际土壤中的丰度显著高于非根际土壤,而厚壁菌门在根际土壤中的丰度低于非根际土壤。两种植物根际土壤中的细菌优势门和优势属的数量均高于非根际土壤,在黑果枸杞和里海盐爪爪的根际土壤中的细菌优势属分别有10个和9个,而二者非根际土壤中的细菌优势属各有4个,其中假单胞菌属是根际和非根际土壤中的共有优势属。黑果枸杞和里海盐爪爪根系细菌群落组成和丰度存在差异,只有假单胞菌属和盐单胞菌属是两种植物根际土壤中的共有优势属。Unifrac分析和聚类分析表明,两种盐生植物根际土壤细菌之间的相似性大于根际和非根际细菌群落间的相似性。细菌多样性与土壤有机碳、有机质、总氮正相关,与pH、电导率负相关,电导率和pH,有机碳和总氮分别是非根际土,根际土壤细菌群落物种组成的主要影响因素。

The rhizosphere soil bacterial diversity and community structures of two halophytes,Lycium ruthenicum and Kalidium caspicum,typically distributed in the arid land of Northwest China,were studied using the high-throughput sequencing technique. The aim of this study was to reveal the rhizosphere soil bacterial community structures and thedifferences between rhizosphere and bulk soil bacterial communities,to provide the basis for further investigation of the relationship between rhizosphere soil microbes and salt tolerance of halophytes. The results show that,the rhizosphere soil bacterial diversity was higher than that of bulk soil,and the rhizosphere soil bacterial diversity of L. ruthenicum was higher than that of K. caspicum. The bacterial community was different in composition and abundance between the rhizosphere and bulk soils. A total of 21 phyla and 289 genera,and 22 phyla and 304 genera were detected in the rhizosphere soil of L.ruthenicum and K. caspicum,respectively. The bulk soils of L. ruthenicum and K. caspicum included 28 phyla and 285 genera,and 24 phyla and 336 genera,respectively. Proteobacteria and Firmicutes were the most abundant phyla in both rhizosphere and bulk soil bacterial communities. The abundance of Bacteroidetes,Actinobacteria,Cyanobacteria,and Planctomycetes in rhizosphere soil was significantly higher than in bulk soil,while the abundance of Firmicutes was lower than in bulk soil. The number of dominant genera in the rhizosphere soils was higher than that in the bulk soils. There were 10 and 9 dominant genera in the rhizosphere soils of L. ruthenicum and K. caspicum respectively,but only 4 genera in bulk soils. Pseudomonas was the only dominant genus in both rhizosphere and bulk soils. Pseudomonas and Halomonas were the common dominant genera of the two plants＇ rhizosphere soil bacterial communities. Unifrac and cluster analysis showed that the similarity between rhizosphere soil bacterial communities of the two plants was greater than that between the rhizosphere and bulk soil bacterial communities. There was a positive correlation between rhizosphere soil bacterial diversity and soil total organic carbon（ TOC）,soil organic matter（ SOM）,and total nitrogen（ TON） contents,and a negative relationship with pH and EC. EC,pH,TOC,and TON were the main influencing factors of both bulk and rhizosphere soil bacterial communities.