Chromobacterium subtsugae sp. nov., a betaproteobacterium toxic to Colorado potato beetle and other insect pests

Abstract

Strain PRAA4-1T, a motile, Gram-negative, violet-pigmented bacterium, was isolated from Maryland forest soil and found to be orally toxic to Colorado potato beetle larvae and other insects. Morphological, biological, biochemical and molecular characterization revealed that this strain was most similar to Chromobacterium violaceum, the type species and only currently recognized member of the genus Chromobacterium. DNA–DNA hybridization with C. violaceum ATCC 12472T was 27 %. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain PRAA4-1T and Chromobacterium violaceum form a monophyletic clade, with the closest ancestral taxon Vogesella indigofera within the Betaproteobacteria. On the basis of phenotypic, genotypic and phylogenetic analyses, strain PRAA4-1T (=NRRL B-30655T=DSM 17043T) is proposed as the type strain of a novel species of the genus Chromobacterium, Chromobacterium subtsugae sp. nov.