Lactic acid bacteria (LAB) as plant growth promoting bacteria (PGPB) for the control of wilt of tomato caused by Ralstonia solanacearum

Bacterial wilt caused by Ralstonia solanacerum is one of the production constraints of tomato (Lycopersicon esculentum Mill). A study was conducted to evaluate the potential of Lactic acid Bacteria (LAB) to suppress the development of wilt pathogen and their role as Plant Growth Promoting Bacteria (PGPB) in tomato. R. solanacerum was isolated from infected tomato plants and their soil samples on triphenyl tetrazolium chloride (TZC) medium. In the in vitro screening, two LAB strains showed maximum inhibition against wilt pathogen. Seed treatment with LAB strains significantly improved the quality of seed germination and seedling vigour. Efficacy of both the strains were evaluated under green house conditions in suppressing incidence of bacterial wilt disease and promoting plant growth in susceptible tomato plant varieties. The disease incidence was significantly reduced by about 63% in plants raised from seed treatment and soil drench method. The present work demonstrates the ability of LAB to act as plant growth promoting bacteria and biocontrol agent against R. solanacearum in vivo.