Screening of Upstream Transcript Factors of IbMYB1-1 by Yeast One-hybrid in Purple-fleshed Sweet Potato

Transcription factors IbMYB1-1 had been identified involving anthocyanins biosynthesis in purple-flesh sweet potato. However, the upstream transcription factors on PIbMYB1-1 involed in anthocyanin biosynthesis had rarely been reported. In this study, the upstream transcription factors on PIbMYB1-1 were screened by yeast one-hybrid screening in purple-fleshed sweet potato storage roots. The results indicated that IbJOX4, IbWRKY1, IbSCF and IbEIN3-2 had been identified as the upstream transcription factors of PIbMYB1-1 to regulated anthocyanin biosynthesis in purple-fleshed sweet potato. The interaction between the promoters and upstream transcription factors were verified by yeast one-hybrid and luciferase reporter assays. Subcellular localization analysis indicated that IbWRKY1, IbSCF and IbEIN3-2 were nuclear proteins and functioned as transcription factors to regulate expression of downstream genes. IbWRKY1, IbSCF and IbEIN3-2 had been identified as the upstream transcription factors of PIbMYB1-1 involved in anthocyanin biosynthesis in purple-fleshed sweet potato. The results provided a possible underlying mechanism of anthocyanin biosynthesis and a potential understanding of the regulatory network in purple-fleshed sweet potato.