Genotypic Characterization Based on 16S rDNA Sequencing and Antimicrobial Properties of Bacterial Endophytes from Garcinia pedunculata

Abstract

Endophytic microorganisms residing within unique environmental niches of medicinal plants are increasingly recognized as significant producers of diverse secondary metabolites with pharmaceutical potential. Garcinia pedunculata, a medicinally important plant of Assam, is traditionally utilized in the tteatment of various ailments such as dysentery, diarrhoea, and jaundice; still its endophytic potential remains largely unexplored. This study framed to isolate and characterize endophytic bacteria associated with G. pedunculata and evaluate their antimicrobial properties. Antimicrobial screening revealed that isolates PDGB-6 and PDGB-7 possessed broad-spectrum activity, exhibiting the highest zones of inhibition (28 mm and 27 mm, respectively) against Klebsiella pneumoniae. Minimum inhibitory concentrations (MIC) were determined for the most potent strains, ranging from 125 µg/ml to 500 µg/ml. The potent isolates PDGB-6 and PDGB-7 were identified as Klebsiella sp. (Accession number KU710415) and Bacillus pumilus (Accession number KU710416), respectively based on molecular identification via 16S rDNA sequencing and phylogenetic analysis using Neighbor-Joining method. Optimization studies indicated distinct temperature and pH requirements for maximum metabolite production. These findings confirm that G. pedunculata harbours novel endophytic bacteria capable of producing potent antimicrobial agents, validating the ethnopharmacological importance of the host plant