Comparative transcriptome analysis reveals metabolic regulation of prodigiosin in Serratia marcescens

Abstract

Prodigiosin is a secondary metabolite mainly produced at 30 °C in Serratia marcescens, but it can hardly be synthetized at 37 °C or higher. In this study, we provide insight into the metabolic regulation of prodigiosin synthesis in response to temperature through transcriptome sequencing. The analysis of the function of differentially expressed genes suggested that temperature resulted in significant alteration of the metabolic pathways between 30 and 37 °C. Specifically, 30 °C favored transcriptional expression of the pig gene cluster. At the same time, the carbon flux was redistributed to pathways of pyruvate, proline, serine, especially homoserine, cystathionine, homocysteine, methionine, and s-adenosylmethionine metabolism, all involved in prodigiosin biosynthesis, and was finally increased towards the prodigiosin synthesis pathway in S. marcescens at 30 °C. Interestingly, results further confirmed increased transcriptional level of five regulators (LuxS, RpoS, Hfq, EepR, CRP), and decreased content of hexS through qPCR. Finally, successful co-overexpression of mmuM and metK, related to homocysteine, methionine, and s-adenosylmethionine metabolism, in the chromosome of JNB5-1 (JNB5-1/MK) resulted in increased prodigiosin titer up to 7.57 g/L in JNB5-1/MK at 30 °C, which was 41.2% higher than that in JNB5-1. Our transcriptome analysis provides further insight into the strain's response to temperature changes at the transcription level, which is of great significance for improving the production of prodigiosin.

Investigating the Role of OrbF in Biofilm Biosynthesis and Regulation of Biofilm-Associated Genes in Bacillus cereus BC1

“…The mutants were constructed using the method according to Sun et al [ 23 ], with slight modifications. For gene knockout, the upstream (containing 9 bp of the gene to be knocked out) and downstream (containing 20 bp of the gene to be knocked out) homology arms of the gene to be knocked out were amplified by PCR.…”

Recent Advances in Prodigiosin as a Bioactive Compound in Nanocomposite Applications

“…This TS activates under a variety of external stress conditions, such as the presence of metal ions with antimicrobial activity, pH changes and high temperatures (>37 °C), resulting in a down-regulation of the expression of prodigiosin and other by-products [ 63 , 64 , 65 , 66 ]. The molecular mechanism of action of this system relies in the detection of such stress factors by the CpxA protein, followed by the phosphorylation of aspartic acid residues located along the structure of the CpxR, allowing its attachment to gene promoters that encodes pig proteins, and impeding their transcription [ 64 , 67 ]. To avoid the effects of this TS, authors developed two transformed strains of S. marcescens JNB 5-1 with suppressed cpxA and cpxR genes, respectively, and evaluated their capability to enhance the prodigiosin synthesis in comparison with a wild strain.…”