IDENTIFICATION OF Xylella fastidiosa subsp. fastidiosa IN CULTIVATED AND WILD PLANTS IN PARRAS, COAHUILA, MEXICO

Abstract

Xylella fastidiosa is a Gram negative bacterium that infects vine plantations (Vitis vinifera L.) in the municipality of Parras, Coahuila, México. This research aimed to identify the subspecies of X. fastidiosa and determine its association with different species of cultivated and wild plants in the municipality. During Summer and Autumn 2018, 83 samples of fruit trees (n = 36), including vine, forest trees (n = 4), ornamental plants (n = 2) and wild plants (n = 41) were collected from two sites in the municipality of Parras. For bacterial identification, partial sequences of the gyrB, HL, and 16S rRNA genes were amplified by PCR, as well as the housekeeping genes (MLST) leuA, petC, malF, cysG, holC, nuoL and gltT, in addition to the pilU adherence to surface gene. Phylogenetic reconstruction showed that the amplified sequences corresponded to X. fastidiosa subsp. fastidiosa. Clade X. fastidiosa subsp. fastidiosa and that the concatenated sequences of the MLST genes were grouped with the sequences ST1, ST2 and ST3, and those of the pilU gene with ST1. Results confirmed the presence of X. fastidiosa subsp. fastidiosa in the cultivated species of Carya sp., Cydonia sp., Ficus carica, Olea europaea and V. vinifera, and in the wild species Celtis pallida, Baccharis sp., Phragmites sp. and Rubus sp. Only in Cydonia sp., O. europaea, Phragmites sp. and V. vinifera scalding symptom was registered on the leaves, a characteristic of X. fastidiosa. Results show the presence of recurrent infections in the municipality of Parras, Coahuila, that represent a source of inoculum of the bacteria for the vineyards, the main crop in the region. This is the first report of X. fastidiosa subsp. fastidiosa in Cydonia sp., which is proposed as a new host for the bacterium.