Control Of Fusarium Wilt Disease In Cowpea Plant (Vigna Unguiculata L.). Using Secondary Metabolites Produced In Bradyrhizobium Japonicum
- Cowpea, Rhizobium, Biocontrol, PGPR and Secondary Metabolites.
Rhizobium known for its nitrogen fixation and plant growth promoting capabilities which is symbiotically associative with legume plants. So forth Rhizobium used as biofertilizers in the agriculture. The ability of controlling plant diseases by using Rhizobium produced secondary metabolites as biocontrol agent is the current open area in the agriculture research. The nodules inhabited Rhizobium strains were selected for the production of secondary metabolites and the ability of controlling Fusarium was evaluated preliminarily by agar well diffusion assay. Four different Rhizobium were isolated, among that S1 cannot showed any inhibition, whereas S2, S3 and S4 were showed 11, 15 and 19mm of inhibition respectively.Among that S4 selected further and DNA isolated and identified using 16S rDNA gene sequencing. The sequences were submitted in genbank and got accession number MH165175. This organism was found to be Bradyrhizobium japonicum and mass cultured for compound extraction using organic solvents. The extracted secondary metabolite were purified using different chromatography techniques. The purified fractions were analyzed for the biocontrol of Fusarium sp., isolated from infected cowpea and results showed fraction 4
showed 21mm zone of inhibition. Further the selected fractions were analytically characterized to know the compounds present. Finally the purified compounds were evaluated for its biocontrol behavior against Fusaium sp., and plant growth promotion in in vitro conditions.