DECIPHERING THE BIOCONTROL MECHANISM OF BACILLUS AMYLOLIQUEFACIENS IIHR BA2: DETECTION OF NEMATICIDAL, FUNGICIDAL AND BACTERICIDAL LIPOPEPTIDES

摘要

Rhizobacteria such as Bacillus spp. have shown great potential as biological interventions against multiple phytopathogenic microbes and nematodes. This investigation was carried out to evaluate the anti nematode and antimicrobial activity of B. amyloliquefaciens IIHR BA2 against root knot nematode; Meloidogyne incognita and a multitude of plant pathogenic fungi and bacteria. The results revealed that the cell free culture filtrates of B. amyloliquefaciens IIHR BA2 recorded 80.82% inhibition in egg hatching of M. incognita and 88.34% mortality of infective juveniles (12) after 72 h. In dual cultures, it caused significant reduction in growth of pathogenic microbes viz., Phytophthora capsici (72.50%), Fusarium oxysporum (65.20%), Sclerotinia sclerotiorum (47.50%), Rhizoctonia solani (45.30%) and Ralstonia solanacearum (52.40%). Several antibiotic genes viz., iturin-A, iturin-C, iturin-D, bacilycin BacD, bacilycin BacAB, surfactin and nematicidal purL gene were detected in its genome. Bioassays on its crude antibiotic extract showed significantly higher J2 mortality, greater suppression in nematode egg hatching and inhibition in growth of the pathogenic microbes. Thus the present study deciphered the antagonistic activity of B. amyloliquefaciens IIHR BA2 through the presence of antibiotic genes and production of secondary metabolites.