Biochemical, physiological, and molecular characterization of Dickeya dianthicola (formerly named Erwinia chrysanthemi) causing potato blackleg disease in Japan

摘要

The taxonomic assignment of Japanese potato blackleg isolates of Dickeya spp. has not been confirmed after the changes in their former name, Erwinia chrysanthemi. Therefore, we investigated and identified 23 representative isolates of Dickeya spp. from symptomatic stems of potatoes in Japan, with biochemical tests and phylogenetic sequence analysis using recA, dnaX, rpoD, gyrB, and 16S rDNA sequences. Results of our biochemical tests showed that all isolates can be assigned to phenon 5 and biovar 1, which are associated with D. dianthicola. Based on the recA, dnaX, rpoD, gyrB, and 16S rDNA sequences, all isolates are in the same clade with D. dianthicola and were clearly distinguished from D. chrysanthemi, D. dadantii, D. dadantii subsp. dieffenbachiae, D. solani, D. zeae, and D. paradisiaca. Therefore, we conclude that Dickeya spp. isolated from potatoes with blackleg symptoms in Japan are D. dianthicola.