Investigating the endophytic bacterial community in special moss species is fundamental to understanding the microbial-plant interactions and discovering the bacteria with stresses tolerance. Thus, the community structure of endophytic bacteria in the xerophilous moss Grimmia montana were estimated using a 16S rDNA library and traditional cultivation methods. In total, 212 sequences derived from the 16S rDNA library were used to assess the bacterial diversity. Sequence alignment showed that the endophytes were assigned to 54 genera in 4 phyla (Proteobacteria, Firmicutes, Actinobacteria and Cytophaga/Flexibacter/Bacteroids). Of them, the dominant phyla were Proteobacteria (45.9%) and Firmicutes (27.6%), the most abundant genera included Acinetobacter, Aeromonas, Enterobacter, Leclercia, Microvirga, Pseudomonas, Rhizobium, Planococcus, Paenisporosarcina and Planomicrobium. In addition, a total of 14 species belonging to 8 genera in 3 phyla (Proteobacteria, Firmicutes, Actinobacteria) were isolated, Curtobacterium, Massilia, Pseudomonas and Sphingomonas were the dominant genera. Although some of the genera isolated were inconsistent with those detected by molecular method, both of two methods proved that many different endophytic bacteria coexist in G. montana. According to the potential functional analyses of these bacteria, some species are known to have possible beneficial effects on hosts, but whether this is the case in G. montana needs to be confirmed.

A Gram-staining-negative, rod-shaped, non-spore-forming bacterium, designated strain R27T, was isolated from the moss Grimmia montana, collected from Beijing Songshan National Nature Reserve, China, and characterized by using a polyphasic taxonomic approach. The predominant fatty acids of strain R27T were C18 : 1ω7c (33.6 %), C16 : 0 (16.3 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 15.8 %) and C17 : 0 cyclo (8.7 %) and its major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, three uncharacterized aminolipids and an unknown phospholipid. Strain R27T contained Q-8 as the dominant isoprenoid quinone and the G+C content of its genomic DNA was 64.6 mol%. On the basis of 16S rRNA gene sequence comparison, strain R27T showed 99.1 % similarity to the closest related type strain, Burkholderia zhejiangensis OP-1T, and 97.6 % similarity to Burkholderia glathei ATCC 29195T. However, the DNA–DNA relatedness between strain R27T and B. zhejiangensis CCTCC AB 2010354T and B. glathei ATCC 29195T was 10.2 and 14.9 %, respectively. Based on 16S rRNA and rpoB gene sequence similarities and phenotypic and chemotaxonomic data, strain R27T is considered to represent a novel species of the genus Burkholderia , for which the name Burkholderia grimmiae sp. nov. is proposed. The type strain is R27T ( = CGMCC 1.11013T  = DSM 25160T).