Identification Of A New Strain Of Xanthomonas Translucens Pv. Unduolsa Parasitizing On Wheat Crop

Abstract

Current study aimed to detect the spreading and virulence of leaf streak disease on wheat in some sites of Najaf province during 2020 season. Pathogenicity test, morphological, chemo-biological and molecular identification of the pathogenic bacteria was conducted. Results of field survey and the spreading of the disease were varied as the percentage of infection in was estimated between 24 and 49%, disease severity between 23.14% and 46.13%. The outcome of pathogenicity test indicated that among 47 isolates tested, 19 showed same symptoms of leaf streak disease and varied in their pathogenicity as the isolate 3 was exceeded other Xanthomonas translucens isolates and reached 46.13%. Identification tests were confirmed that the 19 isolates grown on the specific medium XTS were pale yellow with a dark brown pigment, gram negative and can grow on NA medium as the colonies appeared yellow and glossy opaque. The chemo biological tests showed that isolates were positive to KOH solubility, Aesculin hydrolysis, Catalase, Gelatin and Motility tests and negative to Hydrolysis of starch and Oxidase tests. The identification of bacteria was confirmed by PCR and based on 16S rRNA when new strain of X. translucens was registered in GenBank (NCBI) under the accession number OK287049. Results of current study were beneficial to highlight the spread of bacterial leaf streak disease on wheat in Iraq.