XANTHOMONAS TRANSLUCENS FROM SMALL GRAINS - DIVERSITY AND PHYTOPATHOLOGICAL RELEVANCE

Sixty-eight presumptive Xanthomonas translucens strains isolated from 15 small grains or grass species were studied by pathogenicity tests o n barley, bread wheat, oat, and bromegrass species, and also by AFLP, analysis of fatty acid methyl eaters (FAME), and sodium dodecyl sulfat e-poly acrylamide gel electrophoresis of protein extracts. The X. tran slucens strains were divided into three pathogenicity types based on d ifferences observed on barley and bread wheat. Two unspeciated strains producing atypical symptoms formed a fourth pathogenicity type. Patho genicity on oat and bromegrass species varied within these types. Clus terings observed by AFLP analysis and, to a lesser extent, by FAME ana lysis were consistent with these pathogenicity groupings. The current results, as well as those of previous restriction fragment length poly morphism analyses of the same strains, support the recent reclassifica tion of X. translucens pv. translucens and X. translucens pv. hordei a s true synonyms. X. translucens pv. cerealis, X. translucens pv. trans lucens, and X. translucens pv. undulosa cluster in different groups by AFLP and FAME analyses. Even though distinction by simple biochemical tests is not clear-cut, the data indicate that the pathovars cerea[is , translucens, and undulosa correspond to true biological entities.