Xanthomonas axonopodis pv. dieffenbachiae (Xad) is the causal agent of anthurium bacterial blight and listed as an A2 quarantine organism by EPPO. In support of plant health policies, QBOL generated barcodes for rapid identification of regulated Xanthomonas, including Xad. Xad strains as well as strains from closely related pathovars were collected, consisting of pathotype and well characterized strains from different hosts, geographic origin and isolation year. Strains named as Xad did not represent a single biological entity and were further examined using a polyphasic approach including multilocus sequence analysis (MLSA), DNA-DNA hybridization (DDH), calculations of average nucleotide identity (ANI) values, FAME, Biolog and pathogenicity tests on five aroid hosts. MLSA of seven genes showed Xad strains to cluster into three phylogenetic groups (PG I, II and III) that largely correspond with host from which isolated. Based on ANIb values, DDH data, and phenotypic characteristics, the three PGs each belong to a different species. Taxonomic proposals involve: emendations of existing species and the description of X. dieffenbachiae sp. nov. as a new species, resulting in the classification of Xad strains from PG I, II and III, as X. citri pv. aglaonemae pv. nov., X. euvesicatoria pv. philodendri pv. nov., and X. dieffenbachiae pv. dieffenbachiae sp. nov. comb. nov., respectively. Whole-genome comparative analysis for virulence related factors did not reveal the pathogenic variation among strains observed after host inoculations. The proposed new classification has consequences for several quarantine organisms on the EPPO list.
|Titel||Xanthomonas Genomics Conference|
|Plaats productie||Universidad de los Andes, Bogota, Colombia|
|Publicatiestatus||Gepubliceerd - 8-jul-2015|
|Evenement||5th Xanthomonas Genomics Conference - Bogota, Colombia|
Duur: 7-jul-2015 → 11-jul-2015