Dickeya aquatica sp. nov., isolated from waterways

Abstract

Pectinolytic Gram-negative bacteria were isolated from different waterways in the UK and Finland. Three strains (174/2T, 181/2 and Dw054) had the same 16S rRNA gene sequences which shared 99 % sequence similarity to species of the genus Dickeya , and a phylogeny of related genera confirmed attribution to this genus. Fatty acid profile analysis of all three strains found a high proportion of C16 : 1ω7c/C16 : 1ω7c and C16 : 0 fatty acids, and library profile searches found closest matches to Dickeya chrysanthemi . Production of a concatenated phylogeny using six loci, recA, gapA, atpD, gyrB, infB and rpoB, provided a high-resolution phylogeny which placed strains 174/2T and 181/2 as a distinct clade, separated from the other species of the genus Dickeya by a relatively long branch-length. DNA–DNA hybridization analysis with a limited number of reference species also supported the distinctiveness of strains 174/2T and 181/2 within the genus Dickeya . All three strains could be phenotypically distinguished from other species of the genus by fermentation of melibiose and raffinose but not d-arabinose or mannitol. The name Dickeya aquatica sp. nov. is proposed for the new taxon; the type strain is 174/2T ( = NCPPB 4580T = LMG 27354T).