锦鸡儿属植物功能性状与根际土壤细菌群落结构的关系

以不同地理种群的中间锦鸡儿和小叶锦鸡儿为研究对象，利用高通量测序技术，比较分析了2种锦鸡儿不同地理种群根际土壤细菌多样性、物种组成和丰度的差异及其与植物功能性状的关系，为深入理解锦鸡儿属植物适应干旱环境的微生物学机制提供数据支持。结果表明，2种锦鸡儿根际土壤细菌隶属于22门62纲131目185科304属。优势细菌门为变形菌门、酸杆菌门、拟杆菌门和放线菌门。在属水平上，根瘤菌属、鞘氨醇单胞菌属、RB41和芽孢杆菌属为优势属。中间锦鸡儿与小叶锦鸡儿根际土壤细菌多样性指数（Chao1、ACE、香农和辛普森指数）无明显差异，但主坐标分析表明2种锦鸡儿根际土壤细菌群落结构存在显著差异（P<0.05）。Mantel检验分析表明植物功能性状与根际土壤细菌群落结构存在显著相关性，且冗余分析显示株高、叶干物质含量、比叶面积、叶厚度和叶长是驱动根际土壤细菌群落结构构建的主要性状（P<0.05）。综上所述，中间锦鸡儿和小叶锦鸡儿根际土壤细菌群落结构存在显著性差异，且根际土壤细菌群落结构的变化受到植物性状的显著影响。

Relationship between plant functional traits and rhizosphere bacterial community structure of two Caragana species

In this study， we collected soil samples from Caragana liouana and Caragana microphylla across different geographical populations and the diversity and composition of soil bacterial community were compared and analyzed using Illumina MiSeq high-throughput sequencing technology. Our objective was to test the relationships between plant functional traits and the rhizosphere soil bacterial community， in anticipation this information might provide insight into microbiological mechanisms of Caragana adaptation to drought environments. Results showed that 22 phyla， 62 classes， 131 orders， 185 families and 304 genera were identified from all rhizosphere soils. At the phylum level， the dominant taxa were Proteobacteria， Acidobacteria， Bacteroidetes and Actinobacteria. Rhizobium， Sphingomonas， RB41 and Bacillus were predominant genera. Although the soil bacterial community diversity （Chao1 index， ACE index， Shannon index and Simpson index） showed no significant difference between C. liouana and C. microphylla， a principal coordinate analysis demonstrated that there were significant differences between them in the bacterial community structure. A Mantel test indicated a significant positive relationship between plant functional traits and bacterial community composition of the rhizosphere soil， and furthermore， based on the redundancy analysis， plant height， leaf dry matter content， specific leaf area， leaf thickness and leaf length were the dominant factors associated with changes in the rhizosphere bacterial community structure. Overall， the present results indicate that there are significant differences between C. liouana and C. microphylla in the structure of their soil bacterial communities， and the bacterial community structure of the rhizosphere soil is strongly linked to plant functional traits across the geographical populations.