LAUSR

Biological control with bacterial bioagents is a cost-effective method for the management of foliar diseases of cut flowers under protected conditions. The antagonistic microflora in Lilium ecosystem was exploited and its potential against Botrytis cinerea was assessed for its management. However, the bacterial antagonist Ochrobactrum ciceri has not been explored for management of B. cinerea, a pathogen causing leaf blight of Lilium. In the present study, 42 bacterial antagonists were tested for their antifungal activity against B. cinerea. Among them, the growth of B. cinerea was suppressed up to 46% by O. ciceri (MM17) in vitro. GC/MS analysis of crude metabolites of O. ciceri (MM17) co-cultured with cell wall of B. cinerea produced four antifungal non-volatile metabolites when compared with the solely cultured bacterium. Similarly, gas chromatography/mass spectometry-thermal desorption (GC/MS-TD) analysis of the volatile metabolites of O. ciceri (MM17) indicated that the bacterium produced growth promoting compounds upon interaction with the cell wall of B. cinerea apart from the antibacterial compounds. However, no growth promoting compounds were produced when the bacterium was cultured separately. Further, qRT-PCR analysis revealed an increase in the expression profile of PAL (34.49 folds), PR 10 (4.02 folds) and ascorbate peroxidase (APX) (15.55 folds) transcripts when treated with O. ciceri (MM17), challenged against B. cinerea (SEL). Further, the efficacy of antagonist bacterial strains was assessed for the management of Botrytis leaf blight under protected conditions. Foliar application of O. ciceri (MM17) under protected conditions suppressed leaf blight by 77% and increased the stem yield. This study highlights the potential of O. ciceri (MM17) for the management of Lilium leaf blight under protected cultivation.