Abstract:［Objective］ ArgR，coded by the argR gene from Corynebacterium crenatum AS 1.542，acts as a negative regulator in arginine biosynthetic pathway. However，the effect of argR on transcriptional levels of the related biosynthetic genes has not been reported． Here，we constructed a deletion mutant of argR gene: C. crenatum AS 1.542ΔargR using marker-less knockout technology，and compared the changes of transcriptional levels of the arginine biosynthetic genes between the mutant strain and the wild-type strain.［Methods］We used marker-less knockout technology to construct C. crenatum AS 1. 542ΔargR and analyzed the changes of the relate genes at the transcriptional level using real-time fluorescence quantitative PCR.［Results］C. crenatum AS 1. 542ΔargR was successfully obtained and the transcriptional level of arginine biosynthetic genes in this mutant increased significantly with an average of about 162.1 folds.［Conclusion］ The arginine biosynthetic genes in C crenatum are clearly controlled by the negative regulator ArgR. However，the deletion of this regulator does not result in a clear change in arginine production in the bacteria.