S. P. KAMALA NALINI P, P. SARA VANAN A. ARUMUGAM AND D. LALITHAKUMARI
Abstract
The application of chemical pesticides has come to be a dominant form of pest control, but the emergence of pesticide resistant strains and environmental problems have limited the use of traditional chemical strategies for disease control. In recent years there is a swing to use ecologically safe and "environment friendly" methods of protecting crops from pests and pathogens. The improvement and commercialization of biocontrol agents depends in understanding and exploiting the mechanisms involved in antagonistic interactions among bacteria, pathogens and their plant hosts. Pseudomonas chlororaphis, a soil bacterium, exhibiting versatile antifungal activity, with aggressive spermosphere and rhizosphere colonizing ability - a competitive advantage for biocontrol was isolated. In the current study, the chemotaxis and colonization ability of P. chlororaphis towards seed exudates of paddy, chilli and tomato and its colonization ability on seeds and roots was investigated. The study suggests that P. chlororaphis exhibited positive chemotaxis 'towards plant exudates, which contributes to their rapid colonization in the spermosphere and rhizosphere. This ability in addition to the antagonistc potential makes the pseudomonad a potential biocontrol bacterium.