Maize is a valuable raw material for feed and food production. Healthy seed germination is important for improving the yield and quality of maize. However, the molecular mechanisms that regulate maize seed germination remain unclear. In this study, multi-omics was used to reveal the molecular mechanism of seed germination induced by gibberellin (GA) in maize. The results indicated that 25,603 genes were differentially expressed (DEGs) and annotated in the GO database, of which 2515 genes were annotated in the KEGG database. In addition, 791 mature miRNAs with different expression levels were identified, of which 437 were known in the miRbase database and 354 were novel miRNAs. Integrative analysis of DEGs and miRNAs suggested that carbohydrate, lipid, amino acid, and energy metabolisms are the primary metabolic pathways in maize seed germination. Interestingly, a lipid metabolism-related gene named ZmSLP was found to negatively regulate maize germination. We transformed this gene into Arabidopsis thaliana to verify its function. The results showed that the germination rate of transgenic Arabidopsis seeds was obviously decreased, and the growth of seedlings was weaker and slower than that of WT plants, suggesting that this gene plays an important role in promoting seed germination. These findings provide a valuable reference for further research on the mechanisms of maize seed germination.

Maize is an important food and feed crop. Under limited arable land area, the cultivation of high-density-tolerance crops is a key factor in promoting yield improvement. Leaf width and stalk strength are important influences on density tolerance in maize. However, no comprehensive transcriptomic analysis has focused on maize’s leaf width and stalk strength formation mechanisms. In this study, comparative transcriptomic analyses demonstrated that significant transcriptome changes occurred regarding leaf width and stalk strength of narrow-leaved and wide-leaved maize inbred lines, with a total of 5001 differentially expressed genes (DEGs) identified. Enrichment analysis showed that phenylpropanoid biosynthesis, starch and sucrose metabolism, phytohormone signaling, amino acid metabolism, and brassinosteroid biosynthesis were significantly correlated with the formation of maize leaf shape and stalk strength and that the genes in these pathways were primarily involved in cell wall formation. Weighted gene co-expression network analysis identified 2 modules significantly correlated with leaf width and stalk strength, from which 11 hub genes were further identified. The 11 leaf and stem development genes in different pathways were validated using qRT-PCR. These findings can provide a theoretical basis for the mechanism of narrow-leaf and high-strength stalk formation in high-density-tolerance maize and contribute to the proposal of a breeding strategy for yield improvement.