CcpA-Dependent Carbon Catabolite Repression Regulates Fructooligosaccharides Metabolism in Lactobacillus plantarum

Abstract

Fructooligosaccharides (FOSs) metabolism in Lactobacillus plantarum is controlled by two gene clusters, and the global regulator catabolite control protein A (CcpA) may be involved in the regulation. To understand the mechanism, this study focused on the regulation relationships of CcpA toward target genes and the binding effects on the catabolite responsive element (cre). First, reverse transcription-PCR analysis of the transcriptional organization of the FOS-related gene clusters showed that they were organized in three independent polycistronic units. Diauxic growth, hierarchical utilization of carbohydrates and repression of FOS-related genes were observed in cultures containing FOS and glucose, suggesting carbon catabolite repression (CCR) control in FOS utilization. Knockout of ccpA gene eliminated these phenomena, indicating the principal role of this gene in CCR of FOS metabolism. Furthermore, six potential cre sites for CcpA binding were predicted in the regions of putative promoters of the two clusters. Direct binding was confirmed by electrophoretic mobility shift assays in vitro and chromatin immunoprecipitation in vivo. The results of the above studies suggest that CcpA is a vital regulator of FOS metabolism in L. plantarum and that CcpA-dependent CCR regulates FOS metabolism through the direct binding of CcpA toward the cre sites in the promoter regions of FOS-related clusters.

The local transcriptional regulators SacR1 and SacR2 act as repressors of fructooligosaccharides metabolism in Lactobacillus plantarum

“…Moreover, six LacI-family local transcriptional factors and a TetR-family regulator were identified as presumptive local repressors of arabino-oligosaccharide (AOS) utilization in Bifidobacterium species [43]. According to our previous studies and the present work, FOS metabolism is regulated both globally and locally in L. plantarum [11,12]. CcpA-mediated CCR.…”

“…5b [11]. Specifically, CcpA, a GalR-LacI family protein, is a vital regulator of FOS metabolism in L. plantarum [12]. Previously, we predicted that two local regulators, SacR1 and SacR2, are also involved in the regulation of these two FOS metabolism-related clusters [12],…”

“…CcpA-mediated CCR. This latter process is also the cause of the diauxic growth phenomenon, in which cells resume growing and enter a second growth phase fueled by FOS as the carbon source once glucose is depleted [12]. However, the actual mechanism of regulation may be more complex, as these local regulators are also activated or repressed by CcpA [10,12].…”

“…Subsequently, we demonstrated that CcpA is a vital regulator of FOS metabolism in L. plantarum [12]. However, the mechanism by which FOS metabolism is regulated via local regulators in L. plantarum remains unclear.…”

“…Fructooligosaccharides (FOS) are non-digestible food ingredients that can selectively stimulate the growth and activity of beneficial intestinal microbiota and are considered an established type of prebiotic [4,8,9]. Several studies have demonstrated that L. plantarum can effectively utilize FOS [10][11][12].…”