Genetic diversity of culturable endophytic bacteria in the roots of wild and greenhouse Cymbidium faberi

Abstract

Cymbidium faberi is a representative species of Cymbidium with high ornamental and economic value. Investigating the diversity of C. faberi’s endophytic bacteria not only enriches endophytic bacterial resources, but also provides basic data on orchid-microbe interactions. We investigated the genetic diversity of culturable endophytic bacteria in the roots of wild C. faberi from Tianmu Mountain, Zhejiang Province and C. faberi grown in a greenhouse for one year. Culture-dependent methods were used to isolate endophytic bacteria from the roots of C. faberi. The diversity of these bacteria was investigated using 16S rRNA gene partial sequence analysis. A total of 97 strains were isolated from the interior of wild C. faberi roots. Based on 16S rRNA gene sequences, the 97 isolates were affiliated with 13 genera of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Firmicutes. The dominant group was Gammaproteobacteria (86.60%), and the dominant genus was Lelliottia (26.80%). A total of 52 endophytic strains were isolated from the roots of C. faberi grown in the greenhouse. Based on 16S rRNA gene sequences, the 52 isolates were grouped into 9 genera of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Actinobacteria. The dominant group was Betaproteobacteria (48.08%), and the dominant genus was Herbaspirillum (34.62%). The strain ehR17 was identified as a potential novel species. For C. faberi, the diversity of culturable endophytic bacteria was higher from the wild Tianmu Mountain population than from plants grown in the greenhouse for one year. Community structure of endophytic bacteria was closely related to plant growth environment. 62 生 物 多 样 性 Biodiversity Science 第 23卷