同质环境下不同锦鸡儿属植物根际土壤细菌群落结构差异及其影响因素

Differences in Bacterial Community Structure in Rhizosphere Soil of Three Caragana Species and Its Driving Factors in a Common Garden Experiment

采用高通量测序技术分析同质环境下小叶锦鸡儿、中间锦鸡儿和荒漠锦鸡儿根际土壤细菌多样性及群落结构,以期探讨驱动锦鸡儿属植物根际土壤细菌群落结构构建的关键因子.结果表明,土壤样品中共检测到细菌42门55纲123目244科558属,优势菌门为变形菌门(Proteobacteria)、蓝藻门(Cyanobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)和酸杆菌门(Acidobacteria)(相对丰度>1%),优势属为苯基杆菌属(Phenylobacterium)、剑菌属(Ensifer)和鞘氨醇菌属(Chitinophaga).双因素方差分析表明,物种间差异显著影响土壤细菌香农指数和辛普森指数(P<0.05),种源和物种交互作用对土壤细菌的物种数、Chao1指数、香农指数和辛普森指数均影响显著(P<0.05).主坐标分析表明,3种锦鸡儿属植物根际土壤细菌群落结构差异显著(P<0.05),且聚类分析显示来自不同种源地的中间锦鸡儿和荒漠锦鸡儿根际土壤细菌群落结构组成不同.通过冗余分析发现,种源地的降水量和海拔是影响3种锦鸡儿属植物根际土壤细菌群落结构变化的关键因子.综上所述,3种锦鸡儿属植物根际土壤细菌群落多样性在种间与种内存在显著差异,且种源地气候因子是影响土壤细菌群落结构变化的关键因子,研究结果可为深入理解不同锦鸡儿属植物的环境适应策略和生态修复提供理论依据.

The soil bacterial diversity and community structures in rhizosphere soil of Caragana microphylla,Caragana liouana,and Caragana roborovskyi in a common garden experiment were measured using the high-throughput sequencing technique,with the aim of investigating the factors driving the variation in the bacterial community structure.The results indicated that 42 phyla,55 classes,123 orders,244 families,and 558 genera were obtained from the rhizosphere soil.The dominant phyla in all sample sites were Proteobacteria,Cyanobacteria,Actinobacteria,Bacteroidetes,Firmicutes,and Acidobacteria(relative abundance>1%).At the genus level,Phenylobacterium,Ensifer,and Chitinophaga were dominant.Two-way analysis of variance showed that species had a significant effect on the Shannon index and Simpson index of rhizosphere soil bacteria of the three Caragana species,whereas the Chao1 index,Shannon index,and Simpson index were significantly affected by the interaction of provenances and species.There was a significant difference among the three species in the composition of bacterial communities,and the cluster analysis indicated that the composition of the soil bacterial community significantly differed among provenances in C.liouana and C.roborovskyi.Based on the redundancy analysis,mean annual precipitation and altitude were the dominant factors influencing the rhizosphere soil bacterial community structure.Overall,the present results indicated that there were intraspecific and interspecific differences in the diversity and community structures of rhizosphere soil bacteria,and the bacterial community structure was mainly affected by the provenance climate.These results provide a theoretical basis for understanding the adaptation strategies and ecological restoration of the three Caragana species.