Isolation of endophytic bacteria from bryophytes and study of their morphological, biochemical and biofilm formation properties

Abstract

Aim: To isolate an endophytic bacterial community associated with bryophytes, which were collected from various locations in Mount Abu, Rajasthan, and to characterise their morphological, biochemical, and biofilm development properties. Methodology: Different bryophytes were selected from various regions of Mount Abu, Rajasthan. On an R2A agar plate, colonies with various morphologies were isolated. Biofilm development of bacterial isolates was done on a glass surface and visualised through scaning electron microscopy. Biochemical test, such as indole test, catalase test, urease test, MR and VP tests, citrate utilization test, gelatine and nitrate test, etc., were determined as per Berge’s Manual of Determinative Bacteriology for characterization of endophytic bacteria. Salkowski's technique was also used for estimating IAA production by endophytic bacteria. Results: The results confirmed that isolates belonged to two phyla groups, Firmicutes and γ-proteobacteria with predomination of Firmicutes. Scanning electron microscopy showed that among all the isolates, rod-shaped bacteria dominated. The metabolic properties of endophytic bacteria showed that most bacterial isolates metabolised glucose, maltose and sucrose, however, only few bacterial endophytes metabolized lactose. Some isolates produced IAA growth hormones, which were analysed through Salkowski's technique. Interpretation: The findings indicate that bryophytes have associated bacterial diversity. The morphological and biochemical characterization of bacteria revealed that they are members of the Firmicutes and γ-proteobacteria phyla. SEM confirmed that bacterial isolates can form biofilm on glass surfaces and produce a distinct amount of IAA in a tryptophan-supplemented medium, essential for the growth and development of bryophytes. Key words: Bryophytes, Biofilm, Endophytic bacteria