Genetic Diversity of Xylella fastidiosa in Mexican Vineyards.

Xylella fastidiosa is a xylem-inhabiting phytopathogenic bacterium that affects diverse agriculturally relevant crops. In Mexico, X. fastidiosa has been reported in the states of Baja California, Coahuila, and Querétaro. In order to determine the genetic diversity of this bacterium in Mexico, 408 grapevine samples were collected from the main producing states in México. For X. fastidiosa identification, real-time PCR and three-loci end-point PCR were employed. The genotyping of the subspecies was carried out using multilocus sequence typing and analysis, based on seven housekeeping genes: leuA, petC, malF, cysG, holC, nuoL, and gltT. The resulting sequences were compared with those present in extant databases. The presence of X. fastidiosa subsp. fastidiosa in the states of Baja California (sequence type 1), Coahuila (sequence type 1), and Querétaro was confirmed. The isolates from northern Mexico bear high similarity to grapevine isolates from the United States. However, the isolates from Querétaro showed significant differences with currently known sequences, showing that there is genetic variability among the X. fastidiosa subsp. fastidiosa populations from grapevines in northern and central Mexico.