Expansion of the Host Range of : First Occurrence in Sunflower in Bulgaria.

Sunflower is a short-season crop of the Asteraceae family and the Helianthus genus and is the fourth most important oilseed crop in the world. During a field campaign, unusual symptoms (necrosis and longitudinal cracking of the petiole) were observed in a sunflower crop grown in the region of Kavarna (Dobrich district, Bulgaria) and strains of the genus Xanthomonas were isolated. Results based on phylogenetic and phylogenomic analyses showed that they clustered with Xanthomonas euroxanthea CPBF 424T species, a pathogenic strain isolated from walnut buds in Portugal and responsible for causing walnut bacterial blight (WBB).