Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/7/2015
Publication Date: 11/1/2015
Citation: Lee, S.A., Rogers, E.E. 2015. Identification of novel secreted virulence factors from Xylella fastidiosa using a TRV expression system. Phytopathology. 105:S4.80.
Technical Abstract: Xylella fastidiosa is a bacterium that causes leaf scorch diseases of agriculturally important crops including grapevines and almonds. Little is known about virulence factors that are necessary for X. fastidiosa to grow and cause disease in the xylem vessels of a plant host. Any protein secreted by the bacterium has the potential to interact with the plant host and affect disease. The objective of this study was to identify novel secreted proteins that play a role in the virulence of X. fastidiosa. The X. fastidiosa genome was screened to identify proteins with putative secretion signal sequences. Fifty-eight proteins were identified, cloned in the tobacco rattle virus (TRV) expression system, and screened for pathogenesis in Nicotiana benthamiana. Eight of the fifty-eight proteins conferred increased virulence in N. benthamiana. Expression of these eight proteins in E. coli revealed that four proteins were secreted. Knockout mutants of the four secreted proteins have been constructed and inoculated to grapevines. In vitro assays such as cellular aggregation, surface attachment, and sensitivity to chemical stresses are being performed to phenotypically characterize these proteins. Identification of the full repertoire of virulence factors improves understanding of leaf scorch diseases caused by X. fastidiosa.