ARS | Publication request: Identification of Proteomic Expression of Grapevines in Response to Xylella fastidiosa

Submitted to: American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2007
Publication Date: July 28, 2007
Citation: Yang, L., Lin, H., Takahashi, Y., Walker, A.M. 2007. Identification of Proteomic Expression of Grapevines in Response to Xylella fastidiosa. American Phytopathology Society. 97(7):127

Technical Abstract: Xylella fastidiosa (Xf) is the xylem-limited plant pathogen that causes grape Pierce’s disease (PD) as well as other economically important diseases in a number of fruit and ornamental plants. The objective of this research is to identify differentially expressed proteins in grapevines that are involved in disease development and/or defense responses to Xf infection. We developed a comparative proteomic analysis approach to characterize differentially expressed protein profiles. Total proteins were isolated from stem, leaf and xylem sap of highly susceptible (9621-94) and highly resistant (9621-67) grape genotypes in control and infected treatments at 1, 6, and 12 weeks post-inoculation. Proteins were separated on 2D-PAGE system. Spots representing differentially expressed proteins were excised, digested with trypsin, and detected by oMALDI/TOF/MS and LC/MS/MS. Protein identification was performed by BLAST search of peptide masses and peptide sequences against grape protein databases translated from the available grape EST databases in NCBI. Three up-regulated proteins, thaumatin-like protein, heat shock protein STI (stress-induced protein) and lipoxygenase were identified in the resistant genotype only. The level of differential expression sharply increased for thaumatin-like protein as the disease progressed. In contrast, a putative GTP-binding protein was down-regulated in the susceptible genotype only. In addition, a putative ripening-regulated protein, superoxide dismutase [Cu-Zn], enolase, and three heat shock protein (17.9 kDa, 18.6 kDa and protein 26) were highly expressed in the resistant genotype compared to susceptible genotype. Our findings indicate that the differentially expressed proteins in response to Xf infection are genotype, tissue type and developmental stage dependent. The characterization of these candidate proteins is in progress.