The Differential Expression Of Serratias P.CM01 Protein Under Chromium (Ⅵ) Pressure And Mechanism Of Chromium (Ⅵ) Tolerance

Objective: The results of protein differential expression between wild strain and domesticated strain of Serratia sp. CM01 under Cr(Ⅵ)stress were compared,and explore the response of microorganisms to environmental pollution pressure at the molecular level.Methods: The iTRAQ technique was utilized to investigate the different protein patterns related to the Cr(Ⅵ)-resistance in wild CM01(wCM01)and domesticated CM01(dCM01).RT-qPCR was used to verify the expression levels of several functional genes.The cell surface hydrophobicity and self-aggregation was determined by UV spectrophotometer.The glucose content,total SOD activity and T-GSH content was determined by he intracellular glucose content,total SOD activity and T-GSH content in CM01 were detected by corresponding kits.Results: 2630 proteins were detected and identified in CM01.Compared with wild CM01(wCM01),the iTRAQ results of 646 proteins were found to be significantly different in domesticated CM01(dCM01).RT-qPCR results showed that the expression level of seven genes were consistent with their iTRAQ proteomics data.The cell surface hydrophobicity,self-aggregation,intracellular glucose content,total SOD activity and GSH content of d CM01 cultured with 140 mg/LCr(Ⅵ)were significantly higher than those without Cr(Ⅵ).Conclusion: CM01 displayed a complex biological network to cope with Cr(Ⅵ)stress,which may be attributed to the following:(a) CM01 reduced the consumption of glucose by inhibiting the metabolism of carbohydrates,which is an energy-saving survival mode.(b)Inositol phosphate pathway may play an important role in CM01 tolerance Cr(Ⅵ).(c)Overexpression of oxidative stress proteins enhanced the adaptability.(d)The overexpression of hydrophobic amino acids in CM01 and its self aggregation play a role together.(e)Several key systems and proteins,such as UvrABC system,Lon protease,porin Omp C,also may play an important role.