PHENOTYPIC AND GENOTYPIC CHARACTERIZATION OF Xanthomonas fragariae, CAUSAL AGENT OF THE ANGULAR LEAF SPOT ON STRAWBERRY IN MEXICO

Abstract

Xanthomonas fragariae is the causal agent of angular leaf spot in strawberry (Fragaria × ananassa Duch) in Mexico. The aim of this study was to characterize and identify isolated bacteria based on physiological, biochemical, morphological traits, as well as pathogenicity and genetic tests by PCR. Colonies of bacteria with similar morphology to that described for X. fragariae were isolated from leaf tissue of different strawberry genotypes in Cd. Guzmán, Jalisco, Mexico with symptoms of aqueous angular spots on the adaxial area of leaves, exudate in primary and secondary veins and necrotic spots. The results of the characterization of bacterial isolates identified them as X. fragariae, which was confirmed by genetic analysis through the amplification of the hrp gene, as well as the amplification and sequencing of the 16S rDNA gene. Inoculation of the X. fragariae-22 strain produced angular lesions and necrosis adjacent to the leaf vein on susceptible strawberry plants cv. Jacona.