Effects of Bio-organic Fertilizers Produced by Four Bacillus amyloliquefaciens Strains on Banana Fusarium Wilt Disease

Abstract

ABSTRACTContinuous planting of banana disrupts the micro-ecological balance, resulting in severe fusarium wilt disease caused by Fusarium oxysporum f. sp. cubense (FOC). In this study, fifty-eight antagonistic bacterial strains were isolated from the rhizosphere soils in fields with different soil types and cropping histories, four bacterial strains among which identified as Bacillus amyloliquefaciens, based on 16S rRNA analysis combining with morphological, physiological, and biochemical properties and possessing best survival and antibiotic abilities were further selected. Greenhouse experiments showed that these four bacterial strains were found to observably decrease the fusarium wilt incidence and promote the growth of banana plants when combined with organic fertilizers, demonstrating an effective management strategy. An in vitro assessment using cell-free extracts of liquid culture validated that the four Bacillus antagonists possessed the ability to produce antifungal compounds, including iturin, surfactin, fengycin, and bacillomycin families, all of which were identified by liquid chromatograph-mass spectrometer (LC-MS) analysis during the growth of the antagonists. In addition to lipopeptides, these bacterial strains could also produce volatile antifungal compounds with significant antagonistic effect against FOC. Thus, the work described herein highlights the possibility for using the novel bio-organic fertilizers to control fusarium wilt of banana in the field in the future.