Identification of walnut (Juglans regia) leaf spot agent by its production of species-specific phytotoxin

Abstract

Aim. For the purpose of correct species and internal identification of isolated strains of bacteria that cause walnut leaf spotting, molecular biological and genetic detection of their ability to synthesize the phytotoxin syringomycin have been carried out. Methods. It has been used microbiological and molecular genetic (PCR) methods. Results. The presence of syringomycin (syrD) phytotoxin secretion genes was established in isolated strains of walnut leaf spot pathogen and the typical strain of Pseudomonas syringae pv. syringae UCM B-1027Т. Biotesting of the ability to synthesize syringomycin by these strains revealed the similarity of the antagonistic action of the strains isolated from walnut and the typical strain of Pseudomonas syringae pv. syringae UCM B-1027T, which indicates their ability to synthesize lipodepsinopeptide phytotoxin – syringomycin. Conclusions. Based on the results of the previous researches and presented in this work, strains isolated from walnut were identified as a members of species Pseudomonas syringae pv. syringae.