Bacterial diseases of wheat caused by Xanthomonas sp. in the Southern Ural: Identification issues

Abstract

The identification of pathogenic agents isolated from infected wheat seeds and plants, collected in the Southern Ural and characterized by an atypical manifestation of bacterial infection (yellow leaf tips), has been carried out by direct microbiological and molecular methods. In addition, an indirect identification by the hypersensitive reaction (HR) approach has been performed simultaneously with the pathogenicity assessment of isolates using an indicator plant Plectranthus australis R. Br. Isolated samples have been microbiologically identified as Xanthomonas sp. According to the results of the PCR identification with species-specific primers, isolated samples represent Xanthomonas translucens; the reliability of the obtained results is corroborated by the hypersensitive reaction approach used also to assess the pathogenicity of isolates. Winter wheat, especially cv. Pionerskaya 23, where both X. translucens and Pantoea agglomerans were found, suffered more severe symptoms than spring wheat that was only affected by strains of X. translucens. To improve the reliability of the primary diagnostics of a bacterial character of seed infection, the provoking of the pathogen development by temperature or pH stress is proposed.