GENES REQUIRED FOR TYPE IV PILI FORMATION AND TWITCHING MOTILITY IN XYLELLA FASTIDIOSA

• Author(s): Burr, Thomas; Galvani, C.; Hao, G.; Hoch, Harvey; Li, Y.; Meng, Yizhi;
• Abstract: Xylella fastidiosa (Xf) (Temecula isolate), an important phytopathogen causing Pierces disease (PD) of grapevine, was recently shown to possess both type I and type IV pili. It was also shown that the bacteria exhibit type IV pili-mediated twitching motility on modified PW agar, and possess the ability to migrate preferentially against a flowing current. The EZ::TN transposome system was used to develop twitching-defective mutants. Cloning and sequencing analysis revealed seven associated genes residing in three pil gene clusters, including the pilX cluster (fimT and pilX and pilY1), pilQ cluster (pilQ and pilO) and pilA cluster (pilB and pilR). The fimT, pilX, pilQ, pilO, pilB and pilR mutants lack the twitching phenotype, while the pilY1 mutant colony exhibited significantly reduced twitching. Transmission electron microscopy revealed that no type IV pili were present on the non-twitching mutants, although type I pili were present. Both types of pili are present at one pole of wild type cells. The results suggest that the pil genes disrupted in this study are required for type IV pili formation and twitching motility in Xf.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium