Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2015
Publication Date: 11/1/2015
Citation: Burbank, L. P., Stenger, D. C. 2015. The importance of cold shock proteins in Xylella fastidiosa virulence. Phytopathology. 105:S4.21.
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, and expression is strongly induced by cold temperature. Additionally, CSPs can contribute to cell survival under osmotic stress, and during stationary phase. A putative CSP homolog (Csp1) with conserved cold shock and nucleic acid binding domains was identified in Xf strain Stag’s Leap. As compared with the wild type, a deletion mutant of Csp1 ('csp1) had a decreased rate of survival at 4°C in vitro. Notably, 'csp1 was significantly less virulent in grapevine, as compared with wild type, under normal summer growing conditions. Reduced virulence in the absence of cold stress suggests a broader function of Csp1 in Xf during plant colonization beyond cold tolerance. Further study of the role of CSPs in Xf survival and virulence in planta will lead to a better understanding of pathogen survival under changing environmental conditions, and interaction with the host plant.