Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Abstract only
Publication Acceptance Date: 10/26/2013
Publication Date: 12/16/2013
Citation: Rogers, E.E., Lee, S.A. 2013. Identification of novel secreted virulence factors from Xylella fastidiosa. In: Proceedings of the Pierce's Disease Research Symposium, December 16-18, 2013, Sacramento, California. pp.174. Interpretive Summary:
Technical Abstract: Xylella fastidiosa is a bacterium that causes Pierce’s disease (PD) of grapevine and other leaf scorch diseases of agriculturally important crops. 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 pathogen virulence and/or recognition. Fifty-eight X. fastidiosa proteins with putative secretion signals were identified, cloned into a tobacco rattle virus (TRV) expression vector, and tested for effects on the pathogenesis of TRV in Nicotiana benthamiana. Eight proteins conferred increased pathogenicity to TRV. These proteins are annotated as proteins of unknown function or having a metabolic role suggesting that these proteins may have multiple functions in X. fastidiosa pathogenicity. An E. coli expression system was used to determine protein localization and confirm secretion for the majority of identified proteins. Phenotypic analyses of the identified putative virulence factors are being performed. Additionally, mutations have been constructed in most of the 8 genes, and disease assays in grapevine are underway. Understanding the functions and mechanisms of virulence factors will aid in the development of control strategies for PD.