Late blight of potato caused by the Phytophthora infestans; is well known across the world for its Irish famine in 1845. Whilst chemical pesticides are better in management of late blight, but they are also burden for environment and native microbes. However, unless pathogen co-evolution occurs, resistant varieties play little role in minimising damage caused by late blight. The present study aims at addressing these two issues by isolation of native endophytic bacteria that can provide a new strategy in management of late blight of potato.The dual culture assay revealed that endophytic P. aeruginosa NM314 had strong anti-oomycete activity against P. infestans. Phenazine-1-carboxylic acid was produced by P. aeruginosa NM314 in the zone of inhibition might have a key role in anti-oomycete action. Further, phylogenetic analysis revealed the evolutionary relationship of P. aeruginosa NM314 with 31 strains of P. aeruginosa. Based on these results, the indigenous potato endophyte P. aeruginosa NM314 can be explored an alternative for chemical pesticides to control the late blight of potato.

Phytophthora infestans, Phenazine-1-carboxylic acid, biocontrol; Pseudomonas aeruginosa, NM314, endophyte

In dual culture assay, P. aeruginosa NM314 exhibited various biomolecules when cultured alone and in combination with P. infestans. During di-trophic interaction, it produced PCA, which is a very important antibiotic plays important role in anti-oomycete action. Additionally, the phylogenetic tree construction using neighbor-joining method revealed its close relationship with other P. aeruginosa strains like P. aeruginosa YB01 (China) and formed a separate cluster. At this stage, little is known about the complete mechanisms exhibited by P. aeruginosa NM314 against P. infestans. Evaluation of P. aeruginosa NM314 under field conditions is further required for its effective deployment as a potential biocontrol agent against P. infestans.

K. Mahendra, S. Nakkeeran, T. Raguchander, K. Angappan, U. Sivakumar and L. Arul (2022). Mining the Biomolecules of Pseudomonas aeruginosa Reveals the Anti-oomycetes Nature Against Phytophthora infestans, the incitant of Late Blight of Potato. Biological Forum – An International Journal, 14(2): 645-650.