EFFECT OF SECONDARY METABOLITES PRODUCED BY PSEUDOMONAS AERUGINOSAON ROOT ROT DISEASE IN MUNG BEAN [VIGNA RADIATA (L.) WILCZEK] GROWN ONSALINIZED SOIL

摘要

Rhizobacteria play important roles in the overall growth of plants, influencing it in several ways. The present study was aimed to assess the ability of rhizobacterium Pseudomonas aeruginosa as biocontrol agent and plant growth promoter under both biotic and abiotic stresses. It was observed that the isolated bacterium could tolerate NaCl up to 1.4 M and displayed inhibition of phytopathogen (Rhizoctonia solani) in the presence of up to 400 mM NaCl. The exopolysaccharides and biosurfactant produced by P. aeruginosa showed antifungal activity in presence of NaCl upto 400 mM. The antifungal activity of EPS and biosurfactant against Rhizoctonia solani was about 72% and 63%, respectively, at 100 mM concentration of NaCl, when compared with control (without NaCl). Mutant of P. aeruginosa wereisolated after chemical mutagenesis (2-amino purine treatment), exhibited reduced production of EPS and biosurfactant than the wild type. Besides less production of secondary metabolites, mutant strain DMl"def alsoshowed reduced antimicrobial and salt tolerance property. Extracted biosurfactant and EPS were characterized by FTIR analysis. The present findings demonstrated the role of secondary metabolites (EPS and biosurfactant) of P. aeruginosa against the attackof phytopathogens and salinity stress in Vigna radiata plant.