Metabolome response to temperature-induced virulence gene expression in two genotypes of pathogenic Vibrio parahaemolyticus.
BACKGROUND
Vibrio parahaemolyticus is a main causative agent of serious human seafood-borne gastroenteritis disease. Many researchers have investigated its pathogenesis by observing the alteration of its virulence factors in different conditions. It was previously known that culture conditions will influence the gene expression and the metabolic profile of V. parahaemolyticus, but little attention has been paid on the relationship between them. In this study, for the first time, the metabolomics response in relation to the expression of two major virulence genes, tdh and trh, induced at three temperatures (4, 25 and 37 °C) was examined in two genotypes of pathogenic Vibrio parahaemolyticus (ATCC33846 (tdh+/trh-/tlh+) and ATCC17802 (tdh-/trh+/tlh+)).


RESULTS
Reverse transcription real-time PCR (RT-qPCR) analysis illustrated that the expression levels of tdh and trh induced at 25 °C in V. parahaemolyticus were significantly higher than those induced at 4 and 37 °C. Principal components analysis (PCA) based on the UPLC & Q-TOF MS data presented clearly distinct groups among the samples treated by different temperatures. Metabolic profiling demonstrated that 179 of 1,033 kinds of identified metabolites in ATCC33846 changed significantly (p <0.01) upon culturing at different temperatures, meanwhile 101 of 930 kinds of metabolites changed (p <0.01) in ATCC17802. Pearson's correlation analysis highlighted the correlation between metabolites and virulence gene expression levels. At the threshold of | r | = 1, p <0.01, 12 kinds of metabolites showed extremely significant correlations with tdh expression, and 4 kinds of metabolites significantly correlated with trh expression. It is interesting that 3D, 7D, 11D-Phytanic acid showed the same trend with pyrophosphate, whose derivative could activate the degradation of phytanic acid. Several metabolites could be sorted into the same class by the method of chemical taxonomy, by assuming that they are involved in the same metabolic pathways.


CONCLUSIONS
This research can help to find biomarkers to monitor virulence gene expression, and can further help laboratory and clinical research of V. parahaemolyticus from the perspective of metabolomics.
College of Food Science and Technology, Shanghai Ocean University, No. 999 Hu Cheng Huan Road, Shanghai, China.
Bo
B
Feng
College of Food Science and Technology, Shanghai Ocean University, No. 999 Hu Cheng Huan Road, Shanghai, China.
Zhuoran
Z
Guo
College of Food Science and Technology, Shanghai Ocean University, No. 999 Hu Cheng Huan Road, Shanghai, China.|Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China.|Laboratory of Quality & Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai, China.
Weijia
W
Zhang
College of Food Science and Technology, Shanghai Ocean University, No. 999 Hu Cheng Huan Road, Shanghai, China.|Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China.|Laboratory of Quality & Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai, China.
Yingjie
Y
Pan
College of Food Science and Technology, Shanghai Ocean University, No. 999 Hu Cheng Huan Road, Shanghai, China. yzhao@shou.edu.cn.|Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China. yzhao@shou.edu.cn.|Laboratory of Quality & Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai, China. yzhao@shou.edu.cn.
Yong
Y
Zhao
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D055442:Metabolome; D025341:Principal Component Analysis; D013696:Temperature; D014736:Vibrio parahaemolyticus / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D037521:Virulence Factors
Metabolic profiling; Pearson’s correlation analysis; Relative virulence gene expression; Vibrio parahaemolyticus