Screening and Verification of Transcriptional Regulators Interacted with Potato StSuSy4 Gene

Purpose To explore the transcriptional regulation mechanism of StSuSy4 gene, which is highly expressed in potato tuber.

Methods The promoter of StSuSy4 was cloned, the pAbAi-StSuSy4pro bait vector was constructed, and then transformed into yeast cell Y1HGold to obtain the bait yeast strain. Yeast one-hybrid (Y1H) screen was carried out based on the yeast library built by potato young tuber tissues.

Results Y1H screening yielded a potential transcription factor StBBX25. The open reading frame of StBBX25 was 774 bp, and it encoded a protein of 258 amino acids. Bioinformatic analysis showed that its N-terminal contained the characteristic domain B-box1 of the B-box proteins. Y1H was conducted with the candidate transcription factor and the protomer, and the results showed that under the condition of 200 ng/mL aureobasidin A, yeast cells in pGADT7-AD control group could not grow, while that in PGADT7-StBBX25 experimental group grew well, showing that StBBX25 and StSuSy4 gene promoter interacted. The expression pattern analysis indicated that both StBBX25 and StSuSy4 were highly expressed genes in potato tubers.

Conclusion StBBX25 interacts with StSuSy4 promoter, suggesting that StBBX25 may play a role in starch synthesis and yield formation in potato leaves and tubers. The results provide an important theoretical basis for further understanding of the regulatory network of potato starch synthesis.