GENOTIPIFICACIÓN Y PERFIL BIOQUÍMICO DE AISLADOS DE Xanthomonas albilineans EN VENEZUELA

Xanthomonas albilineans, the causal agent of leaf scald in sugarcane, is characterized by a great variability in its cellular morphology, biochemical and genetic profiles, which are key characteristics in its identification. To achieve the early diagnosis of this disease and to avoid losses of great magnitude, identification protocols should be established for the plant pathogen and its genetic diversity must be assessed. This paper aims to characterize isolated Venezuelan X. albilineans strains by microbiological, biochemical and molecular tests. Bacteria isolated from sugarcane plants cultivars V756, V781 and V99245 with leaf scald symptoms were subjected to differential growth on selective media, Gram staining, hydrolisis of starch, esculin and gelatin and, catalase and oxidase activity. In addition, molecular analysis was performed using DNA amplification with specific primers, as well as ERIC-PCR and REP-PCR analysis. The differential growth and biochemical profiles of Venezuelan isolates LMV08 and LMV02 match the X. albilineans control strain. DNA amplification with specific primers yielded the 288 bp specific band but other bands were obtained as well. With the analysis of dendrograms obtained with ERIC-PCR and REP-PCR, we observed that the isolates have a similitude of 50 and 30%, respectively. The diagnostic strategy employed corroborated the identity of LMV08 and LMV02 as X. albilineans, and also assessed their genetic relationship.