Rep-PCR fingerprinting of Xanthomonas arboricola strains isolated in Chile from Corylus avellana symptomatic plants

In Xanthomonas genus, which includes Gram-negative bacteria mainly phytopathogenic against various host plants, the Xanthomonas arboricola species has a high genetic variability and, among the current 9 pathovars, pv. corylina causes the halzenut bacterial necrosis which is the main disease present in all hazelnut cultivation areas. In this study, 19 X. arboricola and 21 X. arboricola pv. corylina strains isolated in Chile, during 2018, from Corylus avellana symptomatic plants were characterised by Rep-PCR analysis (ERIC, BOX, REP). The genetic profiles of all strains were transformed into binary matrices which were processed by UPGMA method in single or concatenated way using Jaccard similarity coefficient. Thirteen X. arboricola reference strains belonging to the pathovars celebensis, pruni, juglandis and populi were used as controls, while the DISTAL 9081 strain of X. axonopodis pv. vitians was used as outgroup. The UPGMA cluster analysis of Rep-PCR fingerprints divided the 51 X. arboricola strains into 5 statistically significant groups corresponding to the relative pathovars: pruni, corylina, juglandis, celebensis and populi. The X. arboricola pv. corylina strains showed a high genetic variability (approx. 45%). The Rep-PCR fingerprints of the X. arboricola strains isolated from symptomatic hazelnut shoots and leaves gave similar results with a similarity value of approx. 50% among strains which were included in the corylina pathovar