Characterization of Xanthomonas campestris pv. pruni strains from different hosts by pathogenicity tests and analysis of whole‐cell fatty acids and whole‐cell proteins

Abstract

Strains of Xanthomonas campestris pv. pruni obtained from Prunus armeniaca. P. domestica, P. persica and P. salicina in different geographical areas were compared for pathogenicity, fatty acid and wholecell protein analysis. Four strains, one per each host plant, were inoculated at the same time, on the foliage of P. armeniaca, P. avium, P. persica and P. salicina cultivars. Mean content of fatty acids of X.c. pv. pruni strains were also compared with those of many strains of X.c. pv. campestris, pv. graminis, pv. hyacinthii, pv. pelargonii and pv. vasculorum. Strains showed a remarkable homogeneity in fatty acids content and whole‐cell protein profiles and principal component and cluster analysis did not reveal any grouping according to original host or geographical origin. However, X.c. pv. pruni strains can be grouped apart from the other X. campestris pathovars. There appears to be no pathogenic specialization among the strains tested, however, they varied in aggressiveness to host plants and host plant in susceptibility. The most of the strains were able to cross‐infect species other that from where they were originally isolated, although, P. avium did not show any symptom of disease. P. persica cv. Sentry and P. salicina cv. Globe Sun, recently licensed as resistant to X.c. pv. pruni. were infected, although to a lesser extent, by some strains.

Transcriptome reprogramming of resistant and susceptible peach genotypes during Xanthomonas arboricola pv. pruni early leaf infection

“…The source of inoculum for the artificial infections was Xap NCPPB 2588, which was isolated from P . persica in South Africa in 1974, and it is virulent to peach after artificial inoculation [ 40 ]. For inoculum preparation, bacteria were cultured on glucose-yeast extract-calcium carbonate agar plates at 26°C for 48h and suspended in sterile saline (0.85% of NaCl in distilled water) to a concentration of 1–2 × 10 8 colony-forming units (c.f.u.)…”

“…ml -1 . Eight trees of each cultivar (two plants per time point and two control plants) were inoculated on the abaxial side of leaves as described elsewhere [ 40 ] using a high-pressure pumping system to allow the inoculum to penetrate the mesophyll. Control plants were inoculated with sterile saline solution as a mock treatment.…”

Basis for a predictive model ofXanthomonas arboricolapv.prunigrowth and infections in host plants

“…Nevertheless, Xap strains isolated from peach were the most virulent on peach leaves. Despite the fact that the virulence of strains varied, these results confirmed the existence of non-pathogenic specialization and the possibility of crossinfection among hosts (Scortichini et al, 1996).…”

Xanthomonas arboricola pv. pruni

“…‘Friar’, ‘Laroda’, ‘Frontier’, ‘Angeleno’, ‘Black Star’, ‘Shiro’ (Bazzi et al ., 1990; Simeone, 1990). Differences in aggressiveness have been observed among some strains after inoculation in several host plants (Du Plessis, 1988, Scortichini et al ., 1996).…”