The OsMAPK6-OsWRKY72 module positively regulates rice leaf angle through brassinosteroid signals

Area of Science:

• Plant Biology
• Molecular Genetics
• Agronomy

Background:

• Leaf angle is a key determinant of rice plant architecture, impacting yield and photosynthetic efficiency.
• Brassinosteroids (BRs) and MAPK signaling pathways are implicated in leaf angle regulation, but molecular mechanisms remain unclear.

Purpose of the Study:

• To elucidate the role of the OsWRKY72 gene in regulating rice leaf angle.
• To investigate the molecular mechanisms underlying OsWRKY72's function in BR signaling and plant architecture.

Main Methods:

• Phenotypic analysis of OsWRKY72 mutants and overexpression lines.
• Histological examination of lamina joint development.
• Analysis of OsWRKY72 binding to the OsBRI1 promoter.
• Investigation of OsWRKY72 interaction and phosphorylation by OsMAPK6.

Main Results:

• OsWRKY72 positively regulates rice leaf angle, affecting lamina joint development.
• OsWRKY72 mutants show reduced leaf angles and BR insensitivity; overexpression lines show enlarged angles and BR hypersensitivity.
• OsWRKY72 directly binds and activates the OsBRI1 promoter, enhancing BR signaling.
• OsWRKY72 interacts with and is phosphorylated by OsMAPK6, boosting its activity.

Conclusions:

• OsWRKY72 is a crucial transcription factor regulating rice leaf angle through BR signaling and lamina joint growth.
• OsMAPK6, OsWRKY72, and OsBRI1 function in a coordinated pathway to control leaf angle.
• This study provides insights into the molecular networks governing rice plant architecture.