alteration of hyphal morphology and suppression of sporangial production

Abstract

Abstract : The study was conducted with six bacterial strains namely, Delftia sp. strain BTLOOI, Pseudomonas aeruginosa strain BTL002, Pseudomonas sp. strain BTL004, Staphylococcus arlettae strain BTL006, Psseudomonas sp. strain BTL007 and Pseudomonas sp. BTL008, two isolates namely, BTL003 and BTL005 along with two reference strains, Lysobacter capsid 10.4.5 and L. oryzae Y6269 during 2012-2013. All these bacterial isolates and strains except the reference strains were derived from the rhizosphere of host and non host plants including both crops and weeds of seven different locations of Bangladesh. All of them exhibited antagonistic activity against P. capsici on PDA (Potato dextrose agar) medium in dual culture assay. They inhibited the growth of mycelia by producing a clear inhibition zone on PDA medium and exhibited distinct morphological alterations in P. capsid hyphae. Light microscopy analyses revealed that hyphal tips of growth inhibited area showed abnormal morphological features (such as curled, excessively branched and swelled) than those of unaffected hyphae in the control plate. Mycelial dry weight and formation of sporangia of P capsici zoospores were significantly reduced by the application of these bacteria. These results indicate that antagonistic bacteria isolated from Bangladesh could be used as an effective agent for biocontrol of late blight pathogen, P. capsici.