CHARACTERIZATION OF XANTHOMONAS-CAMPESTRIS PV PRUNI STRAINS FROM DIFFERENT HOSTS BY PATHOGENICITY TESTS AND ANALYSIS OF WHOLE-CELL FATTY-ACIDS AND WHOLE-CELL PROTEINS

Strains of Xanthomonas campestris pv. pruni obtained from Prunus armen iaca, P. domestica, P. persica and P. salicina in different geographic al areas were compared for pathogenicity, fatty acid and whole-cell pr otein analysis. Four strains, one per each host plant, were inoculated at the same time, on the foliage of P. armeniaca, P. avium, P. persic a and P. salicina cultivars. Mean content of fatty acids of X.c, pv. p runi strains were also compared with those of many strains of X.c. pv. campestris, pv. graminis, pv. hyacinthii, pv. pelargonii and pv. vasc ulorum. Strains showed a remarkable homogeneity in fatty acids content and whole-cell protein profiles and principal component and cluster a nalysis did not reveal any grouping according to original host or geog raphical origin. However, X.c. pv. pruni strains can be grouped apart from the other X. campestris pathovars. There appears to be no pathoge nic specialization among the strains tested, however, they varied in a ggressiveness to host plants and host plant in susceptibility. The mos t of the strains were able to cross-infect species other that from whe re they were originally isolated, although, P. avium did not show any symptom of disease. P. persica cv. Sentry and P. salicina cv. Globe Su n, recently Licensed as resistant to X.c. pv. pruni, were infected, al though to a lesser extent, by some strains.