Six New Species are Delineated Within Erwinia chrysanthemi

Abstract

After the recent genus reclassification of pectolytic Erwinias into Pectobacterium and Brenneria (1), a taxonomical reclassification of 68 strains belonging to the former E. chrysanthemi species was undertaken using DNA: DNA quantitative hybridization, and phenotypical characterization such as carbon sources for growth, enzyme productions and serological O-typing by immunofluorescence (2). Six genomic species were delineated that were compared to the biovars already described (3, 4). The biovar 1, 7 and 9 strains (isolates from Dahlia, Dianthus, Cichorium, Cynara, Kalanchoe, Lycopersicum, and Solanum) belonged to E. (P.) dianthicola. The biovar 2 strains (isolates from Diejfenbachia, Lycopersicum, and Musa) belonged to E. (P.) dieffenbachiae. The biovar 4 strains (isolates from Musa paradisiaca and Zed) belonged to E. (B.) paradisiaca. The biovars 5 (isolates from Cichorium, Chrysanthemum, Helianthus and Lycopersicum) and 6 (isolates from Cynara, Parthenium, and Philodendron) belonged to E. (P.) chrysanthemi. The biovar 3 was divided into three groups. A group of 20 strains (isolated from 9 sources) including the pathotype zeae strain belonged to E. (P.) zeae. A second group of 16 strains (isolated from 7 sources) formed another new species E. (P.) dadanti, and two strains isolated from Ananas and sugarcane remained unclassified. Criteria are proposed to distinguish between all of the species except between E. zeae and E. dadanti.