不同生境黑果枸杞根际与非根际土壤微生物群落多样性

研究典型生境黑果枸杞根际与非根际土壤微生物群落多样性及其与土壤理化性质间的关系,为进一步研究黑果枸杞抗逆性提供理论数据。采集新疆精河县艾比湖地区(EB)盐碱地、乌苏市(WS)路旁荒地、五家渠市(WQ)人工林带的黑果枸杞根际与非根际土壤,利用Illumina-MiSeq高通量测序技术分析细菌和真菌群落组成和多样性。结果表明:根际土壤细菌多样性高于非根际土壤(WQ除外),而根际真菌多样性低于非根际土壤。WQ非根际土壤细菌和真菌多样性均高于EB和WS;根际细菌多样性排序为EBWSWQ,根际真菌多样性排序为WSEBWQ。根际土壤优势细菌门依次是变形菌门、拟杆菌门、放线菌门、酸杆菌门,真菌优势门为子囊菌门、担子菌门。根际土壤细菌变形菌门、拟杆菌门、酸杆菌门的相对丰度高于非根际土壤,而厚壁菌在根际土壤中的丰度显著降低,真菌优势门丰度在根际土和非根际土中的变化趋势因地区而异; Haliea、Gp10、Pelagibius、Microbulbifer、假单胞菌属、Thioprofundum、Deferrisoma是根际土壤细菌优势属;多孢子菌属、支顶孢属、Corollospora、Cochlonema是根际真菌优势属。细菌、真菌优势类群(门、属)的组成以及丰富度存在地区间差异,厚壁菌门在EB地区的丰富度显著高于含盐量较低的WS、WQ;盐碱生境EB中根际土壤嗜盐细菌的丰度高于非盐碱生境(WQ、WS),如盐单胞菌属、动性球菌属、Geminicoccu、Pelagibius、Gracilimonas、Salinimicrobium等。小囊菌属是EB根际真菌的最优势属,Melanoleuca是WQ和WS的最优势属,地孔菌属、Xenobotrytis、Brachyconidiellopsis、多孢子菌属等在EB根际土壤中的丰度显著高于WQ和WS。非盐碱生境(WS和WQ)的微生物群落之间的相似性较高,并且高于与盐碱环境(EB)之间的相似性,表明土壤含盐量对微生物群落组成丰度具有重要的影响。

The microbial community diversity of the rhizosphere and bulk soils of Lycium ruthenicum in different habitats

The objective of this study was to investigate the microbial (bacterial and fungal) community structure and the relationship between community structure and soil chemical properties in the rhizosphere soil of the halophyte Lycium ruthenicum from different geographical locations (habitats), to provide a theoretical basis for further studies on the relationship between rhizosphere microbiomes and the salt tolerance capacity of Lycium ruthenicum. The rhizosphere and bulk soils were collected from the Ebinur Lake wetland of Jinghe county (EB), Wusu city (WS), and Wujiaqu city (WQ). The bacterial 16S rDNA and fungal 18S rDNA were sequenced with Illumina MiSeq high-throughput sequencing, and we analyzed their diversity and community structure. Results showed that the rhizosphere bacterial diversities were higher than those of bulk soils (except for WQ), whereas rhizosphere fungal diversities were lower than those of bulk soils. The bacterial and fungal diversities in bulk soils of WQ were higher than those of EB and WS. The rhizosphere bacterial diversity order was EB > WS > WQ, whereas the rhizosphere fungal diversity was WS > EB > WQ. The most abundant bacterial phyla in rhizosphere soils were Proteobacteria, Bacteroides, Actinomycetes, and Acidobacteria. Ascomycetes and Basidiomycota were the most abundant phyla in the rhizosphere fungal communities. The relative abundances of Proteobacteria, Bacteroidetes, and Acidobacteria in rhizosphere soils were higher than those in bulk soils, whereas that of Firmicutes was the opposite. The differences in relative abundances of dominant fungal phyla between rhizosphere and bulk soils varied among regions. The most abundant rhizosphere bacterial genera were Haliea, Pelagibius, Microbulbifer, Thioprofundum, and Deferrisoma, and genera Melanoleuca, Cochlonema, and Pleospora dominated the rhizosphere fungal communities. The composition and relative abundances of the most-abundant groups (phyla and genera) differed among regions. The relative abundance of Firmicutes in EB was much higher than those in WS and WQ. Most of the halophilic bacteria, such as Halomonas, Geminicoccu, Pelagibius, Gracilimonas, Salinimicrobium, and Planococcus, had much higher abundances in saline-alkali habitat (EB) than in non-saline-alkali habitat (WQ and WS). Microascus was the most abundant genus in the rhizosphere fungal community of EB, while genus Melanoleuca dominated in the rhizosphere fungal communities of WQ and WS. Additionally, the abundances of Geopora, Xenobotrytis, Brachyconidiellopsis, and Pleospora in the rhizosphere soil of EB were much higher than those of WQ and WS. The rhizosphere microbial communities were distinctly separated from the non-rhizosphere communities. The rhizosphere soil microbial communities in all three regions had high similarity to one another, and the same was true for non-rhizosphere communities. The similarity of the microbial communities of non-saline-alkali habitats (WS and WQ) was higher than that of non-saline-alkali and saline-alkali habitats (EB), indicating that soil electrical conductivity had important influences on microbial community composition and abundance.