Stable isotope labelling by amino acids in cell culture (SILAC) applied to quantitative proteomics of Edwardsiella tarda ATCC 15947 under prolonged cold stress.

Edwardsiella tarda poses a threat to human health and has resulted in enormous economic losses in aquaculture. Low temperatures are usually applied to contain the growth of this microorganism. In this study, stable isotope labelling by amino acids in cell culture (SILAC) was used to conduct comparative proteomic quantitation of E. tarda ATCC 15947 under cold stress for two weeks. We identified 1391 proteins, of which 898 were quantifiable. Of these, 72 proteins were upregulated and 164 were downregulated in response to cold stress. Even though E. tarda ATCC 15947 is not a psychrophile, several key proteins related to DNA synthesis and transcription were significantly upregulated. Additionally, proteins related to haemolytic activities and gluconeogenesis were upregulated, even though E. tarda ATCC 15497 is considered non-virulent in aquaculture. This study therefore delineated the specific proteomic response of this E. tarda ATCC 15947 to prolonged cold stress.