Evaluation of plant growth-promoting activities of endophytic bacteria of Musa acuminata and their characterization

The study was conducted with an aim of isolating and identifying bacterial endophytes associated with Musa acuminata and assessing their plant growth-promoting properties. Endophytic bacteria show mutualistic relationship with plants and help them in alleviating several biotic and abiotic stress without showing any apparent negative effect to the host plant. In the present study, explants samples from different parts of M. acuminata plant such as root, stem, and leaves were collected and cultured. A total of 33 bacterial isolates were obtained and screened for their biotechnological potential for promoting plant growth. From which, 19 isolates were selected for further analysis based on their in vitro plant growth-promoting activities that include indole-3-acetic acid production, phosphate solubilization, nitrogen fixation, ammonia production, hydrogen cyanide (HCN) production, and siderophore production. In addition, these isolates also evaluated for the antagonist activity against Fusarium oxysporum and Macrophomina phaseolina. Among them, five isolates were sequenced, on the basis of 16S rRNA gene sequencing homology of the representative strains was identified EMS1 and EMS4 as Bacillus cereus , EMS13, 14, and 18 as Enterobacter cloacae, and EMS16 as Enterobacter hormaechei. Phylogenetic tree indicated evolutionary relationship of these bacteria to their closely related species. The result of this study demonstrated that based on growth-promoting competencies, all isolated strains have ability that influence the growth of host plants and have potential to be used as effective growth promoting bioinoculant for M. acuminata .