Abstract:

The molecular mechanisms involved in the regulation of potato tuber dormancy are complex, involving a variety of related genes and enzymes, which modulate multiple signaling pathways. Nuclear factor-Y (NF-Y) transcription factors (TFs) are widely found in eukaryotes and are involved in the regulation of plant embryonic development, seed germination, fruit ripening, and in response to biotic and abiotic stress. Previously, we found that StNF-YA8 gene expression was increasing with the release of potato tuber dormancy. In this study, it was found that StNF-YA8 overexpressed tubers broke dormancy earlier than non-transgenic (NT) and StNF-YA8 downregulated tubers. Changes in abscisic acid (ABA) and gibberellin (GA) content of different types of tubers at different dormancy periods confirmed that both GA and ABA hormones influenced the differences in dormancy time. This was confirmed by the expression of GA pathway genes StGA3ox1 and StGA20ox1 genes and ABA pathway genes StCYP707A2 and StPP2CA1 genes in different tubers. The four genes described above were further shown to be target genes of the StNF-YA8 TF, which transcriptionally activates the expression of these genes. In addition, we verified the involvement of StNF-YA8 in the tuber dormancy release process by the interacting proteins StNF-YB20 and StNF-YC5, which are able to bind to the StNF-YA8-B20-C5 module to activate the transcription of GA and ABA pathway genes. Our study reveals the StNF-YA8-C5 module activates the transcription of the StCYP707A2, StPP2CA1, StGA3ox1, and StGA20ox1 genes and alters GA and ABA content, accelerating the release of dormancy in potato tubers.