Dickeya colocasiae sp. nov. isolated from wetland taro, Colocasia esculentum

Bacterial pathogens identified as Dickeya sp. have recently been associated with a corm rot of wetland taro on Oahu, Hawaii, but the species designation of these strains was unclear. A Gram-negative, pectinolytic bacterial strain PL65 T isolated from an infected taro corm was subjected to polyphasic analysis to determine its genomic and phenotypic characteristics. Multi-locus sequence analyses (MLSA) based on five housekeeping genes ( dnaA, gapA, gyrB, atpD , and purA ) revealed that Dickeya zeae and D. oryzae , were the closest relatives. Phylogenetic analysis based on 463 core gene sequences clearly showed two potentially new species within Dickeya oryzae. In silico DNA– DNA hybridization value of strain PL65 T with 12 Type strains of Dickeya species was <68%. Average nucleotide identity (ANI) analysis revealed that PL65 T was at the margin of the species delineation cut-off values with a 96% ANI value. The metabolic profile of strain PL65 T using BIOLOG differentiated it from the type strains of all other known species of Dickeya . Based on the results of genome-to-genome comparisons and phenotypic data presented in this report, we propose establishment of a new species, Dickeya colocasiae sp. nov. with strain PL65 T as the type strain (ICMP 24361 T ).