A Novel OsMPK6-OsMADS47-PPKL1/3 Module Controls Grain Shape and Yield in Rice

Area of Science:

• Plant Biology
• Genetics
• Molecular Biology

Background:

• Grain shape is crucial for rice yield and quality.
• Understanding the genetic regulation of grain shape is essential for crop improvement.
• The complex interactions controlling rice grain morphology are not fully elucidated.

Purpose of the Study:

• To identify and characterize novel regulatory factors controlling rice grain shape.
• To elucidate the molecular mechanism underlying the regulation of grain shape by OsMADS47.
• To establish an integrated regulatory pathway for rice grain shape.

Main Methods:

• Investigated the function of the MADS-box transcription factor OsMADS47 in rice.
• Analyzed the effects of OsMADS47 overexpression and knockout on grain morphology.
• Examined the phosphorylation of OsMADS47 by OsMPK6 and dephosphorylation by PPKL1/3.
• Assessed the transcriptional repression activity of OsMADS47 on target genes GS3 and GW8.

Main Results:

• OsMADS47 overexpression leads to slender grains; knockout results in short, small grains.
• OsMADS47 acts downstream of the OsMKKK10-OsMKK4-OsMPK6 pathway and is phosphorylated by OsMPK6.
• Phosphorylation by OsMPK6 stabilizes OsMADS47 and enhances its repression of GS3 and GW8.
• Dephosphorylation by PPKL1/3 destabilizes OsMADS47 and releases repression on target genes.
• Genetic manipulation of components in this pathway partially rescues phenotypic alterations.

Conclusions:

• A novel regulatory axis involving OsMADS47, OsMPK6, and PPKL1/3 controls rice grain shape.
• OsMADS47 acts as a hub gene integrating upstream signaling to regulate downstream targets.
• This pathway provides a potential target for breeding rice with improved grain appearance quality.