SDS-PAGE: a tool to discriminate Xylella fastidiosa from other endophytic grapevine bacteria

There is a real risk of introducing Xylella fastidiosa into the EPPO region where this quarantine pest has not yet been found and constitutes a serious threat to the Mediterranean grapevine industry. Direct isolation of endophytic bacteria from imported propagation material, combined with one-dimensional SDS-PAGE of the total soluble proteins of the bacterial cell envelope, can be considered as a test to be used in grapevine certification schemes. The gel electrophoretic pattern of Xylella fastidiosa is characterized by a constant distribution of 14 major diagnostic bands. Even without gel scanning, this relatively simple technique allows discrimination between grapevine strains of X. fastidiosa and other xylem-inhabiting, slow-growing bacteria.