Bacterial etiology of necrotic spots on leaves and shoots of grapevine (Vitis vinifera L.) in Poland

Abstract

Dark brown, spotted necrotic areas were observed on the leaves and young shoots of grapevine (Vitis vinifera) plants of cvs. Fanny and Muscat Bleu growing on plantations in Central Poland. From 35 samples of symptomatic leaf and young shoot tissues, 70 bacterial isolates were obtained, of which 16 induced HR on tobacco leaves, but only two showed pectolytic activity on potato tubers and CVP medium. Pathogenicity tests performed with seven selected isolates, including the two pectolytic isolates, on young leaves of grapes cv. Fanny resulted in similar symptoms to those of the plants from which they originated and inoculated bacteria could be re-isolated, confirming Koch's postulates. Using phenotypic tests, analysis of 16S rDNA, housekeeping genes sequences and PCR tests for syrB and syrD genes presence, five of the isolates were identified as Pseudomonas syringae pv. syringae, and the two pectolytic isolates as Xanthomonas arboricola.