The accumulation of chlorophyll and antinutritional glycoalkaloids in potato tubers resulting from exposure to light has been widely recognized as a cause of unpredictable quality loss of potato tuber. While transcriptional regulation of light-induced chlorophyll and glycoalkaloids accumulation has been extensively investigated, the mechanisms of post-transcriptional regulation through miRNA remain largely unexplored. An experimental model, the tubers of Solanum chacoense, were used to identify light-responsive miRNA–target interactions (MTIs) related to tuber greening and glycoalkaloid biosynthesis by employing multi-omics approaches (miRNA-seq and degradome-seq). A total of 732 unique mature miRNAs have been identified in S. chacoense. In total, 6335 unique target transcripts were cleaved by 489 known miRNAs and 153 novel miRNAs. The results revealed that light-responsive miRNAs can be grouped into eight temporally related clusters and play important roles in various physiological processes such as plant growth, stress responses, and primary and secondary metabolism. Multi-omics analyses have revealed that the modulation of transcript abundance of MYB59, HSPs, and EBF1/EBF2 by light-responsive miRNAs is pivotal for their function in cross-tolerance responses to both abiotic and biotic stresses. Furthermore, our findings suggest that many light-responsive miRNAs are crucial regulators in various biosynthetic pathways, including tetrapyrrole biosynthesis, suberin biosynthesis, and steroid biosynthesis. These findings highlight the significant role of light-responsive miRNAs in secondary metabolic pathways, particularly in isoprenoid, terpenoid, and glycoalkaloid biosynthesis, and have implications for the precise manipulation of metabolic pathways to produce new potato varieties with improved resistance to greening and lower glycoalkaloid levels.

Background: Basic (region) leucine zippers (bZIPs) make up one of the largest families and are some of the most prevalent evolutionarily conserved transcription factors (TFs) in eukaryotic organisms. Plant bZIP family members are involved in seed germination, vegetative growth, flower development, light response, and various biotic/abiotic stress response pathways. Nevertheless, a detailed identification and genome-wide analysis of the bZIP family genes in broomcorn millet have not been conducted. Methods: In this research, we performed genome-wide identification, phylogenetic analysis, cis-elements analysis, and expression pattern analysis. Results: 144 bZIP transcription factors were identified from the P. miliaceum genome and classified into eleven subfamilies using a phylogenetic analysis. Motif and bZIP domain sequence alignment analyses indicated that the members in each subfamily were relatively conserved. Furthermore, a promoter analysis revealed that bZIP transcription factor family genes were responsive to multiple hormones and environmental stresses. Additionally, cis-element MYB binding sites were identified in the promoters of most PmbZIP genes. A gene expression analysis showed that 18 PmbZIP genes were differentially expressed during seed germination in salt stress, with 7 being significantly downregulated and 11 upregulated, thus suggesting that these PmbZIP genes may play an important role in the salt stress response and seed germination. Conclusions: Current research provides valuable information for further functional analyses of the PmbZIP gene family and as a reference for future studies on broomcorn millet’s stress response.