毛乌素沙地锦鸡儿（Caragana）根系微域细菌群落多样性特征

基于16S rRNA高通量基因测序技术，对毛乌素沙地小叶锦鸡儿（Caragana microphylla)、柠条锦鸡儿（Caragana korshinskii）根系微域（即根系、根际土、根区土、灌丛间空白土）间的细菌群落多样性和结构差异性进行表征。本研究对各根系微域间细菌群落的Alpha多样性指数进行了单因素方差分析以及基于OTU水平的PCA分析，探究其在根系微域间Alpha和Beta多样性的层级变化，证实了有关植物根系微域生态位分化的报道，并发现锦鸡儿属植物根系微域间细菌群落的多样性和结构组成随着4个微域类型由外及内呈现出显著的层级差异性（P<0.05）。通过对优势细菌群组的结构组成分析，发现锦鸡儿属植物对特定细菌群组具有显著的向根系内筛选富集的作用（P<0.05）。这种植物通过根系微域对特定细菌群组的逐级筛选富集作用，是导致锦鸡儿属植物灌丛下不同生态位间细菌群落结构和组成发生层级变异的主要原因。

Diversity of bacterial communities in the rhizocompartments of Caragana in the Mu Us Desert

Based on 16S rRNA high-throughput genome sequencing, the bacterial diversity and structural variability in the rhizocompartments (i.e.root, rhizosphere soil, root zone soil and inter-shrub bulk soil) of two Caragana spp.(Caragana microphylla and Caragana korshinskii) in the Mu Us Desert are studied.In this study, one-way ANOVA and PCA analysis based on OTU level with Euclidean distance were performed on the Alpha diversity indeices and Beta diversity of bacterial communities in each rhizocompartments, respectively.Then we confirmed the reports on the niche differentiation of plant rhizocompartments, the diversity and structural composition of the bacterial community in the rhizocompartments of desert leguminous plants showed significant differences, with a hierarchical transition of the four rhizocompartment types from outside to inside.We found that desert leguminous plants showed significant hierarchical filtration and enrichment of soil microbial communities under shrubs (P<0.05).The stratified selection and enrichment of specific bacterial groups by the rhizocompartments of plant is one of the main reasons for the hierarchical variation of bacterial community structure and composition in different ecological niches under the shrub of Caragana.