RESUMO
BACKGROUND: Cavendish (AAA) banana plant (Musa spp.) worldwide cultivated crop harbors many endophytic bacteria. Endophytic bacteria are those that live inside plant tissues without producing any visible symptoms of infection. RESULTS: Endophytic bacterium (MRH 11), isolated from root tissue of Musa spp.was identified as Achromobacter xylosoxidans (ON955872) which showed positive effects in IAA production, phosphate solubilization, catalase production. A. xylosoxidans also showed in vitro antagonism against Curvularia lunata causing leaf spot disease of Cavendish (AAA) banana (G-9 variety). The GC-MS analysis of culture filtrate of A. xylosoxidans (ON955872) confirmed this finding. GC-MS analysis was carried by using two solvent etheyl acetate and chloroform and it showed several antifungal compounds. The identification of these bioactive secondary metabolites compounds was based on the peak area, retention time, molecular weight, molecular formula and antimicrobial actions. GC-MS analysis result revealed the presence of major components including Cyclododecane, 1-Octanol, Cetene, Diethyl phthalate. In vivo test to banana plants was carried out in separate field as well as in potted conditions. Appearance of leaf spots after foliar spray of spore of pathogen and reduction in leaf spots after application of bacterial suspension was found. CONCLUSION: The present study has highlighted the role of endophytic bacterium as antagonist to the pathogen Curvularia lunata.