The Arginine Repressor ArgR2 Controls Conjugated Linoleic Acid Biosynthesis by Activating the cla Operon in Lactiplantibacillus plantarum

Xin-Xin Liu; Lei Liu; Xin Song; Guang-Qiang Wang; Zhi-Qiang Xiong; Yong-Jun Xia; Lian-Zhong Ai

doi:10.1128/spectrum.02619-21

Microbiology Spectrum (Jun 2022)

The Arginine Repressor ArgR2 Controls Conjugated Linoleic Acid Biosynthesis by Activating the cla Operon in Lactiplantibacillus plantarum

Xin-Xin Liu,
Lei Liu,
Xin Song,
Guang-Qiang Wang,
Zhi-Qiang Xiong,
Yong-Jun Xia,
Lian-Zhong Ai

Affiliations

Xin-Xin Liu: Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
Lei Liu: Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
Xin Song: Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
Guang-Qiang Wang: Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
Zhi-Qiang Xiong: Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
Yong-Jun Xia: Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
Lian-Zhong Ai: Shanghai Engineering Research Center of Food Microbiology, School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China

DOI: https://doi.org/10.1128/spectrum.02619-21
Journal volume & issue: Vol. 10, no. 3

Abstract

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ABSTRACT CLA (conjugated linoleic acid) has attracted substantial attention due to its physiological functions, including regulating immunity, reducing obesity, and contributing to cancer suppression. In Lactiplantibacillus plantarum, CLA oleate hydratase (CLA-HY), CLA short-chain dehydrogenase (CLA-DH), and CLA acetoacetate decarboxylase (CLA-DC) catalyze the biotransformation of linoleic acid (LA) to CLA. However, the underlying transcriptional regulation mechanism of this pathway remains largely unknown. In this study, the potential transcriptional regulators that might bind to the cla promoter of L. plantarum AR195 were investigated by DNA pulldown. Interestingly, ArgR2, the transcriptional regulator of arginine metabolism, was identified as a potential regulator involved in the regulation of CLA biotransformation. Electrophoretic mobility shift assay (EMSA) and molecular interaction results demonstrated the specific binding of ArgR2 to the regulatory region of the cla operon. The knockout of argR2 led to the downregulation of cla-dh and cla-dc by 91% and 34%, respectively, resulting in a decline in the CLA yield by 14%. A segmental EMSA revealed that ArgR2 bound to three distinct sites in the cla regulatory region, and these binding sites were highly conserved and rich in AT. The regulatory mechanism of ArgR2 on CLA biosynthesis further expanded our knowledge of the regulatory mechanism of CLA biosynthesis in L. plantarum and laid the theoretical foundation for the production and application of CLA. IMPORTANCE CLA (conjugated linoleic acid) has received extensive attention owing to its important physiological functions. CLA from natural sources is far from meeting people’s demands. Lactic acid bacteria can efficiently synthesize cis-9,trans-11-CLA and trans-10,cis-12-CLA, which possess physiological activities. However, little is known about the regulatory mechanism. In this study, we identified that the biosynthesis of CLA in L. plantarum AR195 was transcriptionally regulated by the arginine biosynthesis regulatory protein ArgR2. The regulation mechanism of ArgR2 on CLA biosynthesis lays a theoretical foundation for the regulation of CLA synthesis and industrial production.

Published in Microbiology Spectrum

ISSN: 2165-0497 (Online)
Publisher: American Society for Microbiology
Country of publisher: United States
LCC subjects: Science: Microbiology
Website: https://journals.asm.org/journal/spectrum

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