Isolation and Characterization of diazotrophic endophyte, Asaia bogorensis from Mangifera indica

摘要

During a survey of endophytes in different plants, endophytic bacteria associated with mango ( Mangifera indica ) plants were isolated and identified by studying morphological, physiological and biochemical characteristics. They were tested for the ability to fix nitrogen, produce indole acetic acid (IAA), and solubilize phosphate (P). Plant growth promotion was evaluated through a bioassay using maize ( Zea mays ) as a test plant. The identification of a potent isolate, designated as M6, was authenticated by 16S rDNA nucleotide sequencing and it was identified as Asaia bogorensis . Eleven Gram-negative, aerobic, rod shaped and motile isolates were obtained from different varieties of mango. The isolate M6 reduced acetylene when acetylene reduction assay was performed. This supports its nitrogenase activity. Seven isolates produced IAA. The maximum production of IAA was in the liquid LGI medium supplemented by tryptophan (110 μg/ml). Growth and IAA production was increased by shaking. Four isolates demonstrated phosphate solubilizing ability. Inoculation of the isolate M6 significantly increased roots and shoots biomass of maize after 45 days of growth. This is the first report of the isolation of A. bogorensis from mango plants. The studies indicate that A. bogorensis M6 isolated from mango fruits is beneficial to plant growth.