Antimicrobial activity of bacterial endophytes from Chirata (Swertia chirata Wall.) and Datura (Datura stramonium L.)

Background Exploration of biocides in microbial system becomes increasingly interesting. Among the different microbial systems, the study of endophytes becomes an important field of research because of their agricultural as well as pharmaceutical importance. Bacterial endophytes from two medicinal plants from North Easter states of India had been studied for their potential antibacterial and antifungal properties. Results Bacterial endophytes from two medicinal plant species abundantly available in North Eastern states of India, Chirata (Swertia chirata) and Datura (Datura stramonium), had been isolated and studied for their anti-bacterial and anti-fungal activities. Six bacterial endophytes were isolated from Chirata and 5 from Datura. All these bacterial isolates were initially isolated by observing their colony morphology, and then 9 morphologically distinct bacterial isolates were identified at molecular level by their 16s rRNA sequencing. Among the identified isolates, 5 were found to be belonged to genus Staphylococcus, 2 Bacillus, and one each belonged to Rhodococcus and Cupriavidus. Antibacterial study was carried out against 2 plant pathogenic bacteria, viz., Xanthomonas oryzae and Ralstonia solanacearum. Antifungal study was carried out against 2 plant pathogenic fungi, viz., Fusarium oxysporum and F. solani. Out of 6 bacterial isolates from Chirata, one showed antibacterial as well as antifungal properties, and another one showed antifungal properties only. Likewise, out of 5 bacterial isolates from Datura, one found to have both antibacterial and antifungal properties, and another one has only antifungal properties. Conclusion Few bacterial endophytes isolated from S. chirata and D. stramonium L., abundantly available in North Eastern part of India, had potential antibacterial as well as antifungal properties. This could be considered as the baseline information on potential antibacterial and antifungal agents from bacterial endophytes. Further investigations are required to assess their efficacy against several other bacterial and fungal diseases of economic importance.