- Volume 54, Issue 1, 2004

Bacterial blight is an emerging disease that affects primarily onion, but also garlic and Welsh onion. The present study was undertaken to characterize the causative xanthomonad(s) by a polyphasic approach using a worldwide collection of 33 bacterial strains. Analysis of 16S rRNA gene sequence similarities indicated that the causal agent belongs to the campestris core in the genus Xanthomonas, which is in agreement with results of phenotypic characterization (analyses of carbon source utilization and fatty acid methyl esters). However, DNA–DNA hybridization, thermal stability of DNA reassociation and fluorescent amplified fragment length polymorphism analysis allowed the causal agent to be identified as a pathovar of Xanthomonas axonopodis.

The 16S rRNA gene sequences for 34 strains, including 11 isolates, were determined to classify scab-causing Streptomyces spp. and relatives isolated from potato scab lesions collected in Jeju, Korea. The 16S–23S rDNA internally transcribed spacer (ITS) sequences were determined to investigate whether the 16S–23S ITS region is useful for analysing intra- and interspecific relationships in these bacteria. On the basis of phylogenetic analysis of 16S rRNA gene sequences, most of the isolates were classified as Streptomyces scabiei and Streptomyces acidiscabies. Isolate KJO61 was placed in an ambiguous taxonomic position between Streptomyces reticuliscabiei and Streptomyces turgidiscabies. 16S–23S ITS region sequence analysis showed that tRNA genes were not found in this region of Streptomyces spp. The 16S–23S ITS regions of Streptomyces spp. exhibited various lengths and highly variable sequence similarities (35–100 %) within strains as well as intra- and interspecies. It was revealed that Streptomyces europaeiscabiei could be clearly differentiated from Streptomyces scabiei. However, it was clarified that ITS regions are not useful in phylogenetic analysis of Streptomyces spp.

In the period from January 2001, at least 207 new names proposed in articles in the International Journal of Systematic and Evolutionary Microbiology or cited in Validation Lists are not in accordance with Rules 27(3) and 30 of the Bacteriological Code. The purpose of the present Request for an Opinion is to clarify the status of the names listed and to provide a solution whereby they may be considered to be validly published.

Strains now considered to represent the type strain of Arthrobacter ilicis, described as a pathogen of American holly, are not identical. The designated type strain does not represent this pathogen. However, one of the other strains sourced to the type strain of the pathogen does appear to be authentic, but is not a member of A. ilicis. It is proposed that A. ilicis is an unrelated species, not a pathogen of American holly. The nomenclature of A. ilicis can be rectified by emending the authority and by emending the species description to recognize this species as a novel species that is not a plant pathogen. The pathogen of American holly then becomes a novel pathovar, Curtobacterium flaccumfaciens pv. ilicis. The opinion of the Judicial Commission is sought.

Systematics is the process of characterizing and arranging bacterial diversity in an orderly manner, recognizing groups of similar organisms in a hierarchical scheme whose basic entity is the species. To allow the exchange of scientific knowledge, taxa have to be named. Taxa are not static entities since they are subject to evolution, the direction of which can be inferred by using a wide range of techniques targeting specific traits. However, it is not clear how this dynamism should be reflected in taxonomic nomenclature. In the present report, several considerations are presented that deal with the relationship between the evolution of taxa and their nomenclature; an example is given which concerns the nomenclature of the species Lactobacillus delbrueckii.