Isolation and identification of endophytic bacteria from banana fusarium wilt resistant strains and their inhibitory and growth-promoting effects

Objective To screen and identify endophytic bacteria that can inhibit Fusarium oxysporum f. sp. cubense (Foc) isolated from roots, bulbs and pseudostems of wilt-resistant strains of Williams banana, and study their inhibitory and growth-promoting effects.

Method Through 16S rRNA gene sequence and physiological and biochemical tests, species identification and phylogenetic analysis of endophytic bacteria in banana fusarium wilt resistant strains were carried out. The plate confrontation test was carried out to detect the antibacterial ability of strain and explore the types of antibacterial related active substances secreted by antagonist. The biocontrol and growth-promoting functions of endophytic bacteria in banana resistant strains to wilt disease were analyzed by pot experiment. The endophytes with good biocontrol and growth promoting effects were selected and verified in field.

Result Thirteen representative strains were isolated, among which, there were 8 strains with antibacterial activity against Foc 1 and 7 strains with antibacterial activity against Foc 4. Three biocontrol strains with high inhibitory activity and growth promotion ability were selected by the comprehensive results of biocontrol and growth promoting effects in pot and field experiments, including Bacillus velezensis XG1028, Klebsiella mutans XQJ0301 and Bacillus siamensis XG0103.

Conclusion Three screened strains can enrich the germplasm resources of microorganisms resistant to banana wilt disease, and provide a reference for finding the new safe and environmentally friendly biological control agents controlling banana wilt disease.