Rapid Differentiation, by Polyamine Analysis, of Xanthomonas Strains from Phytopathogenic Pseudomonads and Other Members of the Class Proteobacteria Interacting with Plants

Abstract

A total of 58 strains belonging to phylogenetically assigned or unassigned species of the class Proteobacteria, which are mostly phytopathogenic or might interact with plants, were analyzed for polyamines. The strains of the genus Xanthomonas contained spermidine as the main polyamine. Putrescine was the main polyamine of phytopathogenic strains belonging to the Pseudomonas fluorescens complex, which represents the phylogenetically defined nucleus of the genus Pseudomonas. The genera Azotobacter and Azomonas, which include free-living diazotrophic bacteria that also belong to the P. fluorescens complex, had a polyamine pattern like that of the strains belonging to the P. jluorescens complex. Xylophilus ampelinus (formerly called Xanthomonas ampelina) and unassigned phytopathogenic pseudomonads phylogenetically allocated to the beta subclass of the Proteobacteria contained 2-hydroxyputrescine, the specific polyamine of this subclass. The main polyamine in Rhizobium, Bradyrhizobium, and Phyllobacterium strains and misnamed pseudomonads belonging to the alpha subclass of the Proteobacteria was sym-homospermidine, which was also present in "Azotomonas fluorescens."The status of the genus Xanthomonas has been controversial for decades (7, 20

Polyamine Patterns as Chemotaxonomic Markers for the Genus Xanthomonas

“…They also clearly belong to the genus Xanthomonas on the basis of their fatty acid compositions (33). This finding and the finding described above clearly confirmed the observation of Auling et al (2) that polyamine patterns are useful chemotaxonomic markers for rapid allocation of yellow-pigmented Xanthomonas strains to the genus. The presence of nonpathogenic yellow-pigmented Xanthomonas strains associated with olive leaves, tomato and pepper transplants, bean debris, citrus, soft rots of vegetables at retail markets, apple buds, and rice seeds has been reported previously (4, 1&15, 17, 18 (9).…”

“…The polyamine data confirmed the results of an extensive phenotypic analysis; LMG 962 clustered with X. campestris pathovars, whereas LMG 978, LMG 980, and LMG 981 grouped with X. maltophilia (26). Previously, the polyamine patterns of strains LMG 962 and LMG 978 have both been reported to match pattern I1 (2).…”

“…However, in our hands, X. campestris pv. pelargonii LMG 820 (= DSM 1350) produced a result different from the results of Auling et al (2) in that it did not produce cadaverine.…”

“…The value of polyamine patterns for confirming phylogenetic relationships among phytopathogenic bacteria and other members of the Proteobacteria has been demonstrated previously (1,2,8). In addition, the difficulties in identification of gram-negative, aerobic, yellow-pigmented bacteria which are not associated with plants can be easily overcome by determining polyamine patterns (2).…”

“…However, only six type strains and a few other Xanthomonas strains have been investigated previously, and spermidine was found to be the major polyamine in all strains. Three strains of X. maltophilia and one X. campestris strain (DSM 1350) had high cadaverine contents in addition to high spermidine contents, indicating the chemotaxonomic diversity of the genus Xanthomonas with regard to polyamine profiles (2). The reliability and potential use of polyamine contents as chemotaxonomic markers within the genus Xanthomonas suggested that a larger number of strains should be examined.…”