Objective PqMYB113 transcription factor, a key gene promoting anthocyanin synthesis that gives leaves the red color, and the upstream regulatory mechanism of Paeonia qiui were studied.

Methods A yeast one-hybrid cDNA library was constructed using the Gateway technology. Promoter of PqMYB113 of P. qiui leaves was cloned and verified. 3-amino-1,2,4-triazole (3-AT) was added to the amino acid-deficient medium to self-activate and screen concentration of the promoter. Upstream regulatory factors binding on the promoter were identified using yeast one-hybrid technology.

Results The self-activation inhibition concentration of PqMYB113 was 90mmol·L⁻¹ 3-AT. The constructed cDNA expression library had a capacity of 5.5×10⁶ cfu·mL⁻¹ and a total clone number of 1.1×10⁷ cfu. Through the yeast one-hybrid experiments, 93 upstream regulatory factors of PqMYB113 were screened. They included two transcription factors, one chromatin remodeling factor interaction factor, and one chromatin remodeling factor. The promoter contained environmental response elements on light and stress, hormone response elements on abscisic acid, jasmonic acid, and ethylene, and multiple binding sites for transcription factors, such as MYB and MYC.

Conclusion A yeast one-hybrid cDNA library for P. qiui was constructed. The functional elements on the promoter in the identified upstream regulatory factors of PqMYB113 were predicted. The results provided for further studies on the regulatory mechanism of anthocyanin synthesis and breeding of superior P. qiui varieties.