One of the three PilY1 homologs of X.fastidiosa, which are involved in bacterial twitching motility as component of the filamentous type IV pili (T4P). Expression is not affected by calcium. Shows twitching motility, but the speed of the twitching movement is three times slower than wild-type on a glass surface against the flow direction of media. Mutant cells also move more sporadically with frequent stop intervals. Forms T4P (PubMed:17693510,PubMed:17322192). Not impaired in attachment to surfaces or biofilm formation (PubMed:25217013). Belongs to the PilY1 family.