ISOLATION AND IN-VITRO SCREENING OF POTENTIAL ANTAGONISTIC RHIZOBACTERIA AGAINST PYTHIUM DEBARYANUM

Abstract

A number of rhizobacterial isolates were isolated from the rhizospheric soil that was collected from infected chilli fields during survey. Main objective of the study was to identify the antagonistic bacterial isolates which have potential to restrict or suppressed the growth of Pythium debaryanum, the cause of chilli damping off. Thirty seven bacterial isolates were identified by their colony morphology and biochemical identification tests. Duel culture technique was applied to check the antagonistic behaviour of bacterial isolates. Among thirty seven bacterial isolates in which eleven isolates were shown significance antagonism towards the pathogenic fungal organism. Thirteen bacterial isolates (RB-17,RB-20,RB-21,RB-23,RB-25,RB-26,RB-27,RB-28,RB-31,RB-32,RB-34,RB36,RB-37) rendered between 77 and 96% inhibition while twenty four isolates rendered between 6 and 40%. Maximum inhibition was calculated in case of RB-37 (96%) and RB-34 (77%). Molecular identification was made by isolating bacterial DNA and amplification with 16SrRNA universal primers. PCR products were sequenced and phylogenetic analysis was done. Bacillus subtilis and Pseudomonas fluorescence were finally identified as potential antagonists against P.debaryanum.