Determination of the Anti-bacterial potency of Allium sativum (Garlic) extract against Agrobacterium tumefaciens causing Crown Gall Disease

Abstract

The isolated crown galls (a bacterial plant disease) from Pongamia pinnata leaf were investigated to identify the causative agent. The SEM analysis revealed that the causative agent in crown gall appeared to be a slender, pink and rod-shaped bacterium. The morphological, cultural, biochemical and tumorogenesis analyses were performed to identify causative organisms in the crown gall disease. The isolate was negative for Indole, MR and VP tests, but positive for Citrate, TSI, Urease, Catalase and Oxidase tests. The causative organism also developed a tumor-like sport during the potato disc assay after 3rd week of incubation. The causative agent in crown gall was identified as Agrobacterium tumefaciens. The ethanolic extract of Allium sativum produced an inhibitory zone of 15 mm against this isolate. The current study proved that ethanolic extract of garlic can be effectively used to treat crown gall disease in the economically valuable dicot plant of Pongamia pinnata.