<i>Xanthomonas albilineans</i> (Ashby) Dowson: Study of Its Genetic Variability in Sugarcane Samples in Cuba

Four isolates of the phytopathogenic bacterium Xanthomonas albilineans (Xa) from samples taken in commercial fields of different Cuban provinces and two from the cultivar L55-5, artificially infected in the Camagüey and Matanzas Experimental Stations, were used for the extraction of total nucleic acids according to the CTAB protocol. They were amplified by PCR using four primer combinations: A: P1-M1, B: P1-M2, C: P2-M1 and D: P2-M2. Direct sequencing of the PCR products was performed on all samples and the nucleotide sequences were used to generate partial consensus of 16-23S rRNA, which were analyzed with the BLASTn program. In all the isolates evaluated, the presence of a common band at the height of 620 bp was visualized and the AFLP profile showed that there is homology when comparing the sequences corresponding to the 16-23S rDNA of X. albilineans of the different isolates; the phylogenetic analysis reflected a grouping of the isolates of the species, regardless of its geographical origin, different from others of the genus Xanthomonas. The comparison of the Cuban isolates with eight strains published in GenBank, showed marked similarity with them, with 100% nucleotide identity and percentage of coverage with a genome fragment of the GPE PC73 strain from Guadalupe, KO905 from the United States and a strain from Brazil. The predominance of the generalized circulation in Cuba of a single serovar is presumed.