Pseudomonas viridiflava in imported carrot seeds

Abstract

In 2005, a sample of carrot seeds var. Kikuyo imported from Japan was submitted to the Instituto Biológico for bacteriological phytosanitary certification. Circular, convex and creamy colored colonies were obtained. These isolates produced a green fluorescent pigment on King's B medium and incited a hypersensitivity reaction in tobacco leaves. They were oxidase and arginine dihydrolase negative, did not produce levan but caused soft rot in potato slices and were identified as Pseudomonas viridiflava. Artificial inoculations by infiltration of bacterial suspensions at the crown area or by placing a drop of bacterial suspension on this area and pricking with a sterile needle, produced light to dark brown areas around the injured points 5 days after inoculation. The bacterium was then re-isolated. Although this bacterium could be an opportunistic pathogen and was isolated from asymptomatic samples, eventual losses in the field and post-harvest storage is possible. © 2012 Australasian Plant Pathology Society Inc.