title: Visualization of Twitching Motility and Characterization of the Role of the PilG in Xylella fastidiosa.
abstract: Xylella fastidiosa is a Gram-negative non-flagellated bacterium that causes a number of economically important diseases of plants. The twitching motility provides X. fastidiosa a means for long-distance intra-plant movement and colonization, contributing toward pathogenicity in X. fastidiosa. The twitching motility of X. fastidiosa is operated by type IV pili. Type IV pili of Xylella fastidiosa are regulated by pilG, a chemotaxis regulator in Pil-Chp operon encoding proteins that are involved with signal transduction pathways. To elucidate the roles of pilG in the twitching motility of X. fastidiosa, a pilG-deficient mutant XfΔpilG and its complementary strain XfΔpilG-C containing native pilG were developed. A microfluidic chambers integrated with a time-lapse image recording system was used to observe twitching motility in XfΔpilG, XfΔpilG-C and its wild type strain. Using this recording system, it permits long-term spatial and temporal observations of aggregation, migration of individual cells and populations of bacteria via twitching motility. X. fastidiosa wild type and complementary XfΔpilG-C strain showed typical twitching motility characteristics directly observed in the microfluidic flow chambers, whereas mutant XfΔpliG exhibited the twitching deficient phenotype. This study demonstrates that pilG contributes to the twitching motility of X. fastidiosa. The microfluidic flow chamber is used as a means for observing twitching motility.
authors.affiliation: Department of Plant Science, University of California, Davis.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Shi
authors.affiliation: Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, United States Department of Agriculture; Hong.Lin@ars.usda.gov.
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D018441:Biofilms; D002633:Chemotaxis / Q000502:physiology; D010861:Fimbriae, Bacterial / Q000502:physiology*; D056656:Lab-On-A-Chip Devices; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D009068:Movement / Q000502:physiology; D009876:Operon; D010935:Plant Diseases / Q000382:microbiology; D044167:Xylella / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins