Journal of Environmental Biology

Screening of novel microorganisms for biosurfactant and biocontrol activity against Phytophthora infestans

Sonica Tomar¹, B.P. Singh², Mehi Lal¹*, M.A. Khan¹, Touseef Hussain¹, Sanjeev Sharma², S.K. Kaushik¹ and Satish Kumar³

¹Central Potato Research Institute, Modipuram Campus, Meerut-250 110, India

²Central Potato Research Institute, Shimla -171 001, India

³Meerut College, C.C.S University, Meerut-250 001, India

*Corresponding Author E-mail: mehilalonline@gmail.com

Publication Data

Paper received:

14 March 2013

Revised received:

25 July 2013

Accepted:

05 October 2013

Abstract

In the present study, 95 isolates of bacteria were tested for their biosurfactant as well as biocontrol activity against Phytophthora infestans. The results revealed that only 15.8% isolates showed biosurfactant activity. The emulsification index ranged from 0-68% and 24.2% isolates showed positive reaction for biosurfactant properties. In emulsification assay and oil spreading test, 18.95% and 5.26% isolates, respectively scored positive for biosurfactant production. Among all, only five isolates were found effective against P. infestans, for biocontrol properties. Pseudomonas aeruginosa-1 showed 62.22% inhibition zone after 72 hrs while P. aeruginosa-3 showed 46.42%. Forty-eight hrs old culture supernatants were highly effective in food-poisoning test, tuber slice test and detached leaf method against P. infestans. In whole potato plant test, bacterial cell based formulation, culture supernatant and bacterial cell suspension of P. aeruginosa-1 showed 10.42%, 9.94% and 17.96% diseases severity respectively, as against 53.96% in control. This isolate holds promise as biological control agent against P. infestans in field. 

Key words

Bacteria, Biocontrol, Biosurfactant, Phytophthora infestans, Potato 

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