Determination of the regulatory network and function of the lysR-type transcriptional regulator of Lactiplantibacillus plantarum, LpLttR

BACKGROUND: Lactiplantibacillus plantarum has various healthcare functions including the regulation of immunity and inflammation, reduction of serum cholesterol levels, anti-tumor activity, and maintenance of the balance of intestinal flora. However, the underlying metabolic and regulatory mechanisms of these processes remain unclear. Our previous studies have shown that the LysR type transcriptional regulator of L. plantarum (LpLttR) regulates the biotransformation of conjugated linoleic acids (CLAs) through the transcriptional activation of cla-dh (coding gene for CLA short-chain dehydrogenase) and cla-dc (coding gene for CLA acetoacetate decarboxylase). However, the regulatory network and function of LpLttR have not yet been characterized in L. plantarum. RESULTS: In this study, the regulatory role of LpLttR in various cellular processes was assessed using transcriptome analysis. The deletion of LpLttR had no evident influence on the bacterial growth. The transcriptome data showed that the expression of nine genes were positively regulated by LpLttR, and the expression of only two genes were negatively regulated. Through binding motif analysis and molecular interaction, we demonstrated that the regulatory region of the directly regulated genes contained a highly conserved sequence, consisting of a 15-base long box and rich in AT. CONCLUSION: This study revealed that LpLttR of L. plantarum did not play a global regulatory role similar to that of the other transcriptional regulators in this family. This study broadens our knowledge of LpLttR and provides a theoretical basis for the utilization of L. plantarum.