Liu Xin-Xin, Liu Lei, Song Xin, Wang Guang-Qiang, Xiong Zhi-Qiang, Xia Yong-Jun, Ai Lian-Zhong
Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China.
Microb Cell Fact. 2022 Apr 20;21(1):65. doi: 10.1186/s12934-022-01774-9.
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.
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.
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.
植物乳杆菌具有多种保健功能，包括调节免疫和炎症、降低血清胆固醇水平、抗肿瘤活性以及维持肠道菌群平衡。然而，这些过程潜在的代谢和调控机制仍不清楚。我们之前的研究表明，植物乳杆菌的LysR型转录调节因子（LpLttR）通过转录激活cla-dh（共轭亚油酸短链脱氢酶的编码基因）和cla-dc（共轭亚油酸乙酰乙酸脱羧酶的编码基因）来调节共轭亚油酸（CLA）的生物转化。然而，LpLttR在植物乳杆菌中的调控网络和功能尚未得到表征。
在本研究中，使用转录组分析评估了LpLttR在各种细胞过程中的调控作用。LpLttR的缺失对细菌生长没有明显影响。转录组数据表明，九个基因的表达受到LpLttR的正调控，只有两个基因的表达受到负调控。通过结合基序分析和分子相互作用，我们证明直接调控基因的调控区域包含一个高度保守的序列，由一个15个碱基长的富含AT的框组成。
本研究表明，植物乳杆菌的LpLttR并不发挥与该家族其他转录调节因子类似的全局调控作用。本研究拓宽了我们对LpLttR的认识，并为植物乳杆菌的利用提供了理论基础。
