Evaluation of proposed amended names of several pseudomonads and xanthomonads and recommendations

In 1980, over 90% of all plant-pathogenic pseudomonads and xanthomonads wer e lumped into Pseudomonas syringae and Xanthomonas campestris, respectively , as pathovars. The term "pathovar" was created to preserve the name of pla nt pathogens, but has no official standing in nomenclature. Proposals to el evate and rename several pathovars of the genera Pseudomonas and Xanthomona s to the rank of species has caused great confusion in the literature. We b elieve the following changes have merit and expect to adopt them for public ation in a future American Phytopathological Society Laboratory Guide for I dentification of Plant Pathogenic Bacteria. Upon review of published data a nd the Rules of The International Code of Nomenclature of Bacteria, we make the following recommendations. We reject the proposal to change the name o f P. syringae pvs. phaseolicola and glycinea to P. savastanoi pvs. phaseoli cola and glycinea, respectively, because both pathogens are easily differen tiated phenotypically from pv. savastanoi and convincing genetic data to su pport such a change are lacking. We accept the elevation of P. syringae pv. savastanoi to the rank of species. We accept the reinstatement of X. oryza e to the rank of species with the inclusion of X, oryzicola as a pathovar o f X. oryzae and we accept the species X. populi. We agree with the elevatio n of the pvs. cassavae, cucurbitae, hyacinthi, pisi, and translucens to the rank of species but not pvs. melonis, theicola, and vesicatoria type B. We recommend that all type A X, vesicatoria be retained as X. campestris pv, vesicatoria and all type B X. vesicatoria be named X. exitiosa. We reject t he newly proposed epithets arboricola, bromi, codiaei (poinsettiicola type B), hortorum, sacchari, and vasicola and the transfer of many pathovars of X. campestris to X, axonopodis. The proposed pathovars of X. axonopodis sho uld be retained as pathovars of X. campestris.