CHIP-seq and transcriptomics reveal a new role of circadian-regulated StBBX24 protein in potato reproduction

Background The flowering and tuberization are controlled by common determinants that mediate the regulation of both processes. Among transcription regulators involved in light-dependent aspects of growth and development are B-box zinc finger proteins. To gain a better understanding of the StBBX24 role in flowering and tuber formation, we aimed to investigate the regulatory network of StBBX24 in apical shoot parts at different stages of development and in stolons at the hook stage of tuber formation in StBBX24 -silenced and -overexpressed lines using RNA-seq. In addition, we intended to identify StBBX24-targeted genes specific to the light-dark cycle and potentially involved in potato reproduction by performing CHIP-seq. Results The genome-wide analysis of StBBX24 binding sites identified numerous light- and dark-specific targets, among them those participating in the induction of flowering and floral development. RNA-seq analysis of the apical shoot parts of StBBX24 -silenced and -overexpressed lines revealed substantial modifications in the expression of genes functioning in the flowering process. Furthermore, hook-stage stolons transcriptomics of the transgenic lines revealed that the StBBX24 protein also affects the tuberization process through alteration of the expression of genes participating in stolon-to-tuber transition. Conclusions Altogether, these data reveal that StBBX24 is involved in potato flowering repression and impedes the formation of tubers. Our results provided a more comprehensive understanding of the molecular basis of potato reproduction and the participation of the StBBX24 protein in this process.