title: Diversity of endophytic bacteria associated with nodules of two indigenous legumes at different altitudes of the Qilian Mountains in China.
abstract: A total of 201 endophytic root nodule-associated bacteria collected from two legumes indigenous to different Qilian Mountain altitudes (Hexi Corridor) were characterized through 16S rDNA polymerase chain reaction (PCR)-restriction fragment length polymorphism, 16S rRNA gene sequence analysis, and enterobacterial repetitive intergenic consensus-PCR clustering. The isolates phylogenetically belonged to 35 species in the Phyllobacterium, Ensifer, Rhizobium, Microvirga, Sphingomonas, Paracoccus, Mycobacterium, Paenibacillus, Cohnella, Sporosarcina, Bacillus, Staphylococcus, Brevibacterium, Xenophilus, Erwinia, Leclercia, Acinetobacter, and Pseudomonas genera. Phylogenetic nodA sequence analysis showed higher similarity to Sinorhizobium meliloti with strains related to the Rhizobium, Sinorhizobium, and Acinetobacter genera. Sequence analysis of the nifH gene revealed that the strains belonging to Xenophilus, Acinetobacter, Phyllobacterium, and Rhizobium had genes similar to those of Mesorhizobium and Sinorhizobium. The results indicated that horizontal gene transfer could have occurred between rhizobia and non-rhizobial endophytes. Canonical correspondence analysis revealed that altitude and host plant species contributed more to the bacterial endosymbiont separation than other ecological factors. This study provided valuable information on the interactions between symbiotic bacteria, non-symbiotic bacteria and their habitats, and thus provided knowledge on their genetic diversity and ecology.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Life Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China; Institute of Agricultural and Biological Technology, Hexi University, Zhangye, Gansu 734000, China; Key Laboratory of Western China's Resources and Environment Chemistry, Hexi University, Zhangye, Gansu 734000, China. Electronic address: xulinsjfnubi@163.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.affiliation: Institute of Agricultural and Biological Technology, Hexi University, Zhangye, Gansu 734000, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Life Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Life Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Life Sciences, Northwest A & F University, Yangling, Shaanxi 712100, China. Electronic address: weigehong@nwsuaf.edu.cn.
authors.forename: Gehong
authors.initials: G
authors.lastname: Wei
mesh_terms: D000531:Altitude; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D002681:China; D060026:Endophytes / Q000145:classification*; D007887:Fabaceae / Q000382:microbiology*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D053204:Root Nodules, Plant / Q000382:microbiology*
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Altitude; Diversity; Endophytes; Phylogeny; Rhizobia