Multi-scale analysis of seed dormancy in Lonicera maackii and functional identification of LmABI5 in promoting...

Lonicera maackii is a valuable medicinal shrub whose propagation is hindered by deep seed dormancy. Research on L. maackii seeds has been limited to dormancy classification and release methods, with little attention given to biochemical indices, systematic omics, or molecular mechanisms. In this study, we showed that seed dormancy in L. maackii can be effectively released through cold stratification treatment. Furthermore, using hyperspectral imaging technology, we established a non-destructive method for identifying the dormancy status of L. maackii seeds. Ultrastructural observations revealed that dormancy release involved lipid droplet degradation and nucleolar enlargement, indicative of activated metabolism. Biochemical indices showed that dormancy-released seeds exhibit enhanced metabolic activity. In addition, target hormones contents indicated a decline in abscisic acid (ABA) and a rise in gibberellic acid (GA) upon dormancy termination in this species. Moreover, transcriptomic analyses demonstrated that differentially expressed genes (DEGs) were primarily enriched in plant hormone signal transduction pathways, among which we identified LmABI5 as a gene markedly induced during dormancy compared to its expression upon dormancy release. Subsequently, subcellular localization analysis revealed that LmABI5 is localized in the nucleus. To further investigate its biological function, we generated and selected LmABI5-overexpressing (LmABI5-OE) transgenic Arabidopsis lines. Germination assays revealed that the seeds of LmABI5-OE plants exhibited significantly stronger dormancy than those of the wild-type (WT). This study deepens our understanding of regulatory network and provides a theoretical foundation for molecular breeding strategies in L. maackii.