Objective The interaction and expression of 7 upstream transcription proteins (IbERF1, IbPDC, IbPGP19, IbSCF, IbWRKY1, IbJOX4 and IbEIN3-2) of purple-fleshed sweet potato IbMYB1 were analyzed to further elucidate the regulatory network of anthocyanin synthesis and accumulation in specific time and space.

Method Yeast two-hybrid and BiFC experiment were used to detect the interactions between the 7 upstream transcription regulators. RT-qPCR was used to analyze the gene expression traits of an thocyanin synthesis regulation and upstream regulators in purple-fleshed sweet potato and white-fleshed sweet potato at roots different developmental stages.

Result IbERF1 interacted with IbSCF and IbWRKY1. BiFC experiment confirmed the results of yeast two-hybrid experiment. The expression level of IbERF1 gene in purple-fleshed sweet potato roots was lower than that in white-fleshed sweet potato at different periods, and the expression level decreased gradually with the accumulation of anthocyanin in root. The expression levels of IbWRKY1 and IbSCF genes in the roots of purple-fleshed sweet potato and white-fleshed sweet potato at different developmental stages showed no significant positive or negative correlation with anthocyanin accumulation.

Conclusion The upstream regulatory proteins IbERF1 can form a complex with IbSCF and IbWRKY1, respectively to co-regulate the expression of IbMYB1 in the form of a transcription complex. It is speculated that IbERF1 may negatively regulate anthocyanin synthesis, and IbSCF and IbWRKY1 may be involved in the synthesis and regulation of anthocyanin in purple-fleshed sweet potato.