Prospective of biosurfactant in management of fusarium wilt and early blight of Lycopersicon esculentum

Abstract

Biosurfactants are eco-friendly compounds, which exhibit low toxicity, high stability, and biodegradability, and cater multiple ecological services. To study the prospectus of biosurfactant in management of plant diseases, the present study was undertaken. Previously isolated and characterized three native biocontrol microbes, Pseudomonas aeruginosa Tr20, Bacillus subtilis BS6, and B. subtilis CS13, were screened for the ability to produce biosurfactant. Among three isolates, only P. aeruginosa Tr20 confirmed positive result for production of biosurfactant. The biosurfactant was extracted (yield 0.815 g/l) and characterized for functional groups present through FTIR. The biocontrol attribute of biosurfactant was screened under in-vitro condition at four different concentrations, i.e., 100, 200, 400, and 800 mg/L against pathogens Fusarium oxysporum f. sp. lycopersici (Fol) and Alternaria solani. The result obtained showed that the highest growth reduction of Fol and A. solani, the causal agent of fusrium wilt and early blight was 36.82 and 39.90%, respectively, at 800 mg/l of biosurfactant. To increase the activity spectrum of biosurfactant, a consortium of biosurfactant (200 mg/l) was prepared with a compatible strain of T. lixii TvR1, and the biocontrol activity was evaluated under in-vivo condition. The result obtained for pot experiment (90 days after transplantation) was observed to reduce fusarium wilt and early blight incidence by 27.21 and 29.43%, respectively. The study concluded that the biosurfactant is a sustainable option for management of fungal pathogens, and its consortium with compatible microbial strains can be formulated to amplify its biocontrol potential.