| Popis: |
Aquaculture farming practices in India and other countries are facing a lot of economic loss due to luminescent vibriosis.Ecological and cost-effective practices may have been warranted to combat this tricky disease. A total of 57 morphologicallydifferent marine bacterial isolates were isolated from samples collected at different aquaculture ponds in Marakkanam, Tamil Nadu,India and screened for their antibacterial potential against luminescent vibriosis causing bacteria Vibrio harveyi. All marine bacterialisolates were screened for antibacterial activity by cross streak method against two different isolates V. harveyi GNC01 and V.harveyi GNC03. Secondary screening of antagonistic isolates by dual culture plate method and agar well diffusion method leads tothe identification of antagonistic isolates. The antagonistic isolates were characterized by molecular taxonomy (16S rRNA genesequence) and phylogeny and identified as Neobacillus niacini (GNC04), Bacillus halotolerans (GNC06), Bacillus amyloliquefaciens(GNC16), Lacticaseibacillus paracasei (GNC23) and Lactiplantibacillus plantarum (GNC24). The minimum inhibitory concentrationof all these selected bacterial crude secondary metabolites against both Vibrio harveyi isolates GNC01 and GNC03 ranged between0.062 to 0.50 mg/mL. The GC-MS profiling of the ethyl acetate extract revealed the presence of antibacterial compounds such asOxime-,methoxy-phenyl (26.63%), 2,3-Dihydroxybutane (9.52%), Phosphite, menthyldimethyl- (2.83%), Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl)- (2.07%). The results of this study suggest that Lactiplantibacillus plantarum (GNC24) is apotential source for antagonistic secondary metabolites against luminescent vibriosis causing bacteria Vibrio harveyi. Further,biological control formulation with these isolates and their metabolites will be a reward for the integrated pest management inthe aquaculture sector. |
