Abstract
Sinoacutine synthetase (SinSyn) is one of the key enzymes in the biosynthesis pathway of sinomenine (SIN), an effective pharmacological component in Sinomenium acutum. However, the transcriptional regulation mechanism of this gene in the SIN synthesis pathway has not been studied. In this study, a 1520 bp upstream promoter sequence and three 5' terminal truncations were used to drive the GUS reporter gene to test their activities in transiently expressed tobacco and stable transgenic Arabidopsis. Both the full-length promoter and the truncated promoters can initiate GUS expression. As the 5' end is removed, their activity is different. The results of GUS histochemical staining showed that − 956 bp ~ -622 bp was an important position of SinSyn gene promoter. In addition, bioinformatics analysis revealed that various regions of the SinSyn promoter were distributed with some abiotic stress and plant hormone activation. Through transgenic Arabidopsis thaliana verification, it was confirmed that the SinSyn gene promoter could respond to methyl jasmonate (MeJA), auxin (NAA, IBA), drought, and NaCl. The MeJA response elements were located at -1520 bp ~ -956 bp, the auxin response elements were located at -622 bp ~ -395 bp, the drought response elements were located at -395 bp ~ -1 bp and the NaCl response elements were located at -956 bp ~ -1 bp. In general, our study provides a theoretical reference for the application of pSinSyn in biological stress resistance, the functional verification of the SinSyn gene, and the regulation of SIN synthesis in Sinomenium acutum.