Role of endophytic Penicillium species and Pseudomonas monteilii in inducing the systemic resistance in okra against root rotting fungi and their effect on some physiochemical properties of okra fruit.

AIMS:The efficacy of three isolates of endophytic Penicillium species that have shown significant suppressive effect on root rotting fungi in our previous study were further evaluated in pots and field plot experiments for their effect on root diseases of okra, induction of systemic resistance and physiochemical properties of okra fruit. METHODS AND RESULTS:Aqueous suspensions of endophytic Penicillium and Pseudomonas monteilii were applied in pots and field plots using okra as test plant. Data on the fungal infection of roots, plant growth, plant resistance markers like polyphenol, salicylic acid and antioxidant status of plant were determined. These isolates significantly suppressed root diseases and induced systemic resistance via increasing level of resistance markers, polyphenol and salicylic acid besides improving antioxidant activity of Penicillium and P. monteilii-treated plants as compared to control plants. GC-MS analysis of n-hexane extract of mycelium of P. nigricans revealed the presence of 15 different volatile compounds. CONCLUSIONS:Endophytic Penicillium and P. monteilii have potential against root-infecting fungi of okra and can improve plant growth and yield. SIGNIFICANCE AND IMPACT OF THE STUDY:Endophytic Penicillium species and P. monteilii can suppress root rotting fungi by direct mechanism or induction of systemic resistance in plants.