A brassinosteroid responsive miRNA-target module regulates gibberellin biosynthesis and plant development

Area of Science:

• Plant biology
• Molecular genetics
• Hormone signaling

Background:

• Plant growth and development are regulated by brassinosteroid (BR) and gibberellin (GA) hormones.
• The intricate relationship and signaling crosstalk between BR and GA pathways in rice remain largely unexplored.

Purpose of the Study:

• To elucidate the molecular mechanisms underlying the interaction between brassinosteroid and gibberellin signaling in rice.
• To identify key regulatory elements and pathways that connect BR and GA in coordinating plant growth.

Main Methods:

• Investigated the role of OsmiR159d and its target OsGAMYBL2 in BR and GA signaling.
• Utilized gene expression analysis, protein-protein interaction studies, and promoter binding assays.
• Examined the impact of BR and GA signaling components (OsGSK2, SLR1) on the OsmiR159d-OsGAMYBL2 module.

Main Results:

• Brassinosteroid (BR) suppresses OsmiR159d, leading to increased levels of its target OsGAMYBL2.
• The OsmiR159d-OsGAMYBL2 module regulates genes involved in BR signaling (BU1) and GA biosynthesis (CPS1, GA3ox2).
• BR signaling component OsGSK2 stabilizes OsGAMYBL2, while GA signaling component SLR1 inhibits its promoter binding; GA signaling promotes OsGAMYBL2 degradation, enhancing BR signaling.

Conclusions:

• A BR-responsive module (OsmiR159d-OsGAMYBL2) acts as a crucial link between BR and GA pathways in rice.
• This module connects BR signaling to GA biosynthesis, coordinating plant growth and development.
• The findings reveal a novel crosstalk mechanism essential for plant hormonal regulation.