Pectobacterium aroidearum sp. nov., a soft rot pathogen with preference for monocotyledonous plants

Abstract

Several pectolytic bacterial strains, mainly isolated from monocotyledonous plants and previously identified as Pectobacterium carotovorum , were thought to belong to a novel species after several taxonomic analyses including DNA–DNA hybridization. In 16S rRNA gene sequence analyses, these strains had a similarity of >97.9 % to the 16S rRNA gene sequence of strains representing six other pectobacterial species and subspecies. These strains, represented by strain SCRI 109T, also showed some unique chemotaxonomic features and quantitative differences in polar lipids, lipoquinones and fatty acids. A specific feature of strain SCRI 109T was the presence of DMK-8 lipoquinone, while the dominant fatty acids were the summed feature 3 (iso-C15 : 0 2-OH/C16 : 1ω7c), the unsaturated fatty acid C18 : 1ω7c and straight chain fatty acids, mainly C16 : 0. The DNA G+C content of strain SCRI 109T was 50.2 mol%. The taxonomic status of strain SCRI 109T and related strains in 16S rRNA gene sequence, chemotaxonomic, and physiological analyses was corroborated by the distinct clustering of these strains in multi-locus sequence analyses. It is proposed that these strains represent a novel species for which the name Pectobacterium aroidearum sp. nov. is proposed; the type strain is SCRI 109T ( = NCPPB 929T = LMG 2417T = ICMP 1522T).