Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 11/17/2014
Publication Date: 12/3/2014
Citation: Burbank, L.P., Stenger, D.C. 2014. Role of cold shock proteins in Xylella fastidiosa virulence. CDFA Pierce's Disease Research Progress Reports. p. 91.
Technical Abstract: Xylella fastidiosa (Xf), causal agent of Pierce’s Disease (PD) of grapevine, is mainly prevalent in warmer climates. Subjecting Xf-infected grapevines to cold temperatures can, in many cases, effectively eliminate the bacterial population, a phenomenon known as cold curing. However, very little is known regarding the physiological response of Xf to cold temperatures. Cold shock proteins (CSPs), a family of nucleic acid binding proteins, are known to be an important component in the response of bacteria to temperature downshift. Genes encoding CSPs are often present in multiple copies; expression is strongly induced by cold temperature or in stationary phase as part of a general stress response. In some cases, bacterial CSPs are recognized by the plant host as an elicitor of the basal defense response. Two putative CSP homologs (Csp1 and Csp2) with conserved cold shock and nucleic acid binding domains were identified. A deletion mutant of Csp1 ('csp1) in Xf strain Stag’s Leap had a decreased rate of survival at 4°C, as compared with wild type. Wild type survival rates at 4°C were partially restored in 'csp1 by complementation with the predominant CSP of Escherichia coli (CspA), or the CspA homolog of Xanthomonas campestris. Most notably, 'csp1 was significantly less virulent in grapevine, as compared with wild type. Further study of the role of CSPs in Xf survival and virulence in planta will lead to a better understanding of the cold curing phenomenon observed in PD affected grapevines and interactions of Xf with the plant host.