EPIDEMIOLOGY AND MANAGEMENT OF XYLELLA FASTIDIOSA (XF) AND OTHER EXOTIC AND INVASIVE DISEASES AND INSECT PESTS
Location: Crop Diseases, Pests and Genetics
Title: Identification and characterization of proteomic expression of grapevines in response to Xylella fastidiosa infection.
Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: October 8, 2011
Publication Date: December 13, 2011
Citation: Lin, H., Yang, L., Walker, M.A. 2011. Identification and characterization of proteomic expression of grapevines in response to Xylella fastidiosa infection. CDFA Pierce's Disease Control Program Research Symposium, Dec 13-15, 2011, Sacramento, California. p. 210.
Xylella fastidiosa (Xf) is the bacterial causal agent of Pierce’s disease (PD) of grapevines, as well as of other economically important diseases in a number of agronomic, horticultural and ornamental plants. In this study, comparative proteomic analyses were carried out to identify proteins differentially expressed in Xf- infected grape stems from a pair of siblings of 9621-67 (highly resistant) and 9621-94 (highly susceptible) grapevines, cross of Vitis rupestris x V. arizonica. The identification of proteins and their expression pattern under given physiological conditions is of fundamental importance for functional analyses of cellular processes associated with PD development and resistance. The proteins were isolated from the stems of healthy and Xf-inoculated plants at 1, 6, and 12 weeks after inoculation. The total proteins were then separated by a 2D-PAGE system and the spots representing differentially expressed proteins were analyzed by an oMALDI-TOF-MS/MS Mass Spectrometry. Protein identification was performed using BLASTp and tBLASTn against NCBI non-redundant protein databases and EST databases. Ten proteins that were differentially expressed at different time points after inoculation were identified. A thaumatin-like protein and the pathogenesis-related protein 10 from both genotypes, and the 40S ribosomal protein S25 from the susceptible genotype were up-regulated in response to Xf-infection. Furthermore, the expression of the thaumatin-like protein increased sharply 12 weeks post-inoculation in the PD-resistant genotype only. Three heat shock proteins, 17.9 kDa class II, protein 18 and 21 were highly expressed in healthy tissues compared with those in tissues infected with Xf. In addition, a down-regulated putative ripening related protein was found in the Xf-inoculated PD-susceptible genotype. Glycoprotein and formate dehydrogenase were identified in the PD-resistant genotype and their expression was constant during plant development. A putative GTP-binding protein was down-regulated in the PD-susceptible genotype. The results revealed that differential expression of proteins in response to Xf-inoculation was genotype and tissue development stage dependent. The specific roles of these candidate proteins in alleviation or aggravation of this disease are under investigation. The information obtained in this study will aid in the understanding of the mechanisms related to the host-pathogen interactions involved in PD.