Biological control of red rot in sugarcane by native pyoluteorin-producing Pseudomonas putida strain NH-50 under field conditions and its potential modes of action.
BACKGROUND
Rhizobacteria have a good potential to suppress soilborne diseases, but their efficacy against sugarcane pests is rarely reported. Bacterial strains isolated from the rhizosphere of sugarcane were evaluated for their potential to suppress red rot disease on two susceptible varieties, Co-1148 and SPF-234, under field conditions. The strains were also characterised for the production of secondary metabolites associated with their antagonistic activity.


RESULTS
One out of four strains, the Pseudomonas putida strain NH-50 (EU627168), reduced disease severity by 44-60% in different field trials. This potent antagonistic strain produced pyoluteorin antibiotic, as confirmed by high-performance liquid chromatography (HPLC). The PltB gene involved in pyoluteorin synthesis was amplified from the P. putida strain NH-50 and sequenced. The extracellular metabolites and volatile and diffusible antibiotics secreted by the tested strains inhibited mycelial growth of Glomerella tucumensis (Speg.) Arx & E Mull in vitro by 7-55%.


CONCLUSION
The pyoluteorin-producing bacteria P. putida strain NH-50 significantly reduced disease severity on both sugarcane varieties, irrespective of fungal inoculation, i.e. either inoculated through stem or through soil. This strain also possesses other plant growth characteristics and can be used as a biopesticide for sugarcane crop.
['Hassan|Muhammad N|MN|', 'Afghan|Shahid|S|', 'Hafeez|Fauzia Y|FY|']
D000900:Anti-Bacterial Agents D010572:Pest Control, Biological D010636:Phenols D020081:Phyllachorales D010935:Plant Diseases D016958:Pseudomonas putida D011758:Pyrroles D058441:Rhizosphere D031786:Saccharum D012988:Soil Microbiology
red rot sugarcane Pseudomonas putida pyoluteorin biocontrol