RG介导KAR/SL调控种子萌发的分子机制探究

Karrikins (KARs) share the butenolide structure with strigolactones (SLs) and similarly possess the ability to promote seed germination. However, the molecular mechanisms by which KAR and SL signaling regulate seed germination remain unclear. Previous studies identified that the Arabidopsis gene AtDRG is homologous to the rice pre-harvest sprouting gene OsSDR4. Phenotypic observations of the drg smax1 double mutant revealed a restoration of the strong germination phenotype seen in the smax1 mutant, indicating that DRG is a key downstream factor in the Karrikin pathway regulating seed germination, though its precise molecular mechanism requires further investigation. Therefore, this study employed yeast two-hybrid, luciferase complementation assay, bimolecular fluorescence complementation, and GST-pull down interaction experiments to demonstrate that DRG can interact with KAI2 and D14 in a hormone molecule-independent manner. Further analysis revealed that the interaction of KAI2 and D14 with DRG enhances DRG\'s transcriptional repression activity, thereby regulating seed germination. This research lays the foundation for elucidating the molecular mechanism by which DRG responds to KAR signaling, transduces the signal to downstream targets, and ultimately influences seed germination.