Modified Liquid Dual Culture Methodology for Screening Bacterial Endophytes Against Fungal Pathogens

摘要

A modified methodology for screening bacterial endophytes against fungal pathogens was developed. This method is modified form of liquid dual culture assay which can provide rather appropriate information of antagonistic activity of the endophyte. Results indicated that the endophytes have shown significant suppression of pathogens by multiple mechanisms in the mixed culture. In this study, the modified methodology was compared with routinely followed screening methods in two soil borne pathogens Rhizoctonia solani and Sclerotium rolfsii of tomato. In modified method, lowest Rhizoctonia solani biomass (54.47mg) was observed from 6TH4b inoculation as compared to 218.52 mg in control. In Sclerotium rolfsii also, lowest biomass (18.84mg) was observed from 6TH4b inoculation as compared to 334.07 mg in control. Dual plate assay has shown maximum suppression of 70.81 per cent of Rhizoctonia solani and 78.02 per cent of Sclerotium rolfsii by endophyte 2PR9b. Host tissue extract enhanced the antagonistic potential of bacterial endophytes and the effect was pronounced in 3 A, where pathogen biomass suppressed by 26.51 mg as compared to that of 130.43 mg without host tissue extract. Isolates 3A, 6TH4b, 1TH16, 4R4 AND 4PR19 performed poorly in routine dual culture assay but found to have excellent suppression of pathogens by modified method. This modification can be effectively used for primary screening of endophyte bacteria for biological control.