Antifungal activity of some non-fluorescent Pseudomonas bacteria isolated from Phaseolus vulgaris L. rhizosphere
Slimane Mokrani, Lakhder Belabid, El-hafid Nabti
Biological control is an alternative of synthetic chemicals that have secondary and harmful effects on environment. In this context, 10 non-fluorescent Pseudomonas isolated from bean rhizosphere were characterized for PGP traits and antifungal activities against various phytopathogenic fungi. Characterizations of biosurfactants produced by the non-fluorescent Pseudomonas revealed particularly Rhamnolipid production by (P2, P3, P5, P6 and P7). They showed a surface tension reduction varying from 35.04 % to 64.75%. All strains produced salicylic acid in quantities of 3.1 mg/ml to 16.9 mg/ml. Only two strains P10 Pseudomonas cepacia and P7 Pseudomonas plantarii produced HCN (134.64 ppm and 87.12 ppm), respectively. Study of Antifungal activities of the non- fluorescent Pseudomonas showed that all isolates exerting very highly significant inhibition of mycelium growth of Fusarium, Penicillium, Aspergillus and Mucor. Percentages inhibition observed ranged from 32.42 % to 100%. The combination of Pseudomonas pseudo mallei and Pseudomonas cichorii showed the best result of fungal inhibition. The less active bacteria, was isolate P10 Pseudomonas cepacia. Thus, non-fluorescent Pseudomonas endowed with PGP traits could have a potential inhibition of various phytopathogenic fungi.