Serratia marcescens Quinoprotein Glucose Dehydrogenase Activity Mediates Medium Acidification and Inhibition of Prodigiosin Production by Glucose

Abstract

<jats:title>ABSTRACT</jats:title><jats:p><jats:named-content content-type="genus-species">Serratia marcescens</jats:named-content>is a model organism for the study of secondary metabolites. The biologically active pigment prodigiosin (2-methyl-3-pentyl-6-methoxyprodiginine), like many other secondary metabolites, is inhibited by growth in glucose-rich medium. Whereas previous studies indicated that this inhibitory effect was pH dependent and did not require cyclic AMP (cAMP), there is no information on the genes involved in mediating this phenomenon. Here we used transposon mutagenesis to identify genes involved in the inhibition of prodigiosin by glucose. Multiple genetic loci involved in quinoprotein glucose dehydrogenase (GDH) activity were found to be required for glucose inhibition of prodigiosin production, including pyrroloquinoline quinone and ubiquinone biosynthetic genes. Upon assessing whether the enzymatic products of GDH activity were involved in the inhibitory effect, we observed that<jats:sc>d</jats:sc>-glucono-1,5-lactone and<jats:sc>d</jats:sc>-gluconic acid, but not<jats:sc>d</jats:sc>-gluconate, were able to inhibit prodigiosin production. These data support a model in which the oxidation of<jats:sc>d</jats:sc>-glucose by quinoprotein GDH initiates a reduction in pH that inhibits prodigiosin production through transcriptional control of the prodigiosin biosynthetic operon, providing new insight into the genetic pathways that control prodigiosin production. Strains generated in this report may be useful in large-scale production of secondary metabolites.</jats:p>

Isolation, Characterization, and Growth Promotion of Phosphate-Solubilizing Bacteria Associated with Nicotiana Tabacum (Tobacco)

“…For example, gluconic acid is a major organic acid produced by many gram-negative bacteria during phosphate solubilization and is produced by several plant growth-promoting bacteria (PGPB) [27,42]. Our results also show that P solubilization was related to the secretion of organic acids.…”

Serratia marcescens Cyclic AMP Receptor Protein Controls Transcription of EepR, a Novel Regulator of Antimicrobial Secondary Metabolites

“…Mutation of genes involved in 3=-5=-cAMP production (cyaA) and the transcription factor that responds to cAMP (crp) confers robust phenotypes beyond catabolite repression, including increased prodigiosin production (18), elevated serratamolide pro-duction (19), increased biofilm formation through increased type I pili production (20), enhanced extracellular protease production (21), and a loss of flagellum-based motility (22). CRP similarly regulates motility, adhesion, and secondary metabolite production by such diverse bacteria as Salmonella enterica serovar Typhimurium and Streptomyces coelicolor (1)(2)(3)(4).…”

Identification of a methicillin-resistant Staphylococcus aureus inhibitory compound isolated from Serratia marcescens

“…S. marcescens was mutated using mariner transposon delivery vector pSC189 and mutations were mapped as previously described (Chiang and Rubin, 2002) (Fender et al, 2012). The plasmids used in the study were reported elsewhere (Shanks et al, 2009, 2013, 2012), except for pMQ262 noted below.…”