Identification and characterization of Xanthomonas arboricola pv. corylina causing bacterial blight of hazelnut: a new disease in Poland.

Abstract

In the years 2007 and 2009 leaf spots and cankers were observed on different hazelnut cultivars grown in one orchard in central Poland. In both years yellow colony-forming bacteria were isolated from the margin of diseased and apparently healthy tissue. Fifteen isolates tested positive in a PCR assay using primers X1 and X2 specific for bacteria belonging to the genus Xanthomonas. Results of most of the physiological and biochemical features determined in our study agreed with those given in the EPPO standard PM 7/22, but some of them (utilization of L-arabinose, maltose, glycerol, D-xylose, lactose and raffinose) differed. However, they were identical with those of the reference strain Xanthomonas arboricola pv. corylina (Xac) LMG 688. The 15 isolates tested were also identified as Xac on the basis of cellular fatty acid content converted to methyl esters (FAME) as well as in gyrB gene sequence analysis. All isolates showed pathogenic ability on young leaves of potted hazelnut plants cv. Webb’s Prize Cob in a greenhouse test and could be re-isolated from symptomatic tissues. In rep-PCR (BOX, ERIC and REP-PCR) all isolates showed patterns very similar to reference Xac strains (LMG 688, CFBP 1159). Peculiarly, a slight difference in the rep-PCR patterns of isolates recovered in 2007 and 2009 was found. This is the first time that Xac and hazelnut blight are found in and reported from Poland.