A dose-sensitive miR164e-WRKY50-JAZ7 module fine-tunes grain size in rice

Area of Science:

• Plant Biology
• Genetics
• Evolutionary Biology

Background:

• Polyploidization enhances crop traits like yield through genetic variation.
• Tetraploid rice has larger grains, suggesting potential for yield increase, but its genetic regulation is poorly understood.

Purpose of the Study:

• To construct the first comprehensive mRNA and microRNA atlas during tetraploid rice grain development.
• To elucidate the regulatory mechanisms controlling grain size in polyploid rice.

Main Methods:

• Comparative transcriptomic analysis of tetraploid and diploid rice during grain development.
• Integrated mRNA and microRNA analysis to build regulatory networks.
• Functional validation of key genes and microRNAs using mutation and DAP-seq.

Main Results:

• Identified dose-sensitive transcription factors and hormone signaling genes in tetraploid rice grain development.
• Constructed a microRNA-target network revealing dose-sensitive miRNAs regulating grain size.
• Validated the miR164e-WRKY50-JAZ7 module, showing miR164e negatively regulates WRKY50, which activates JAZ7, impacting grain weight.

Conclusions:

• Established a dose-sensitive regulatory network controlling polyploid rice grain size.
• Uncovered the novel miR164e-WRKY50-JAZ7 module as a key mechanism for polyploid advantage in grain development.
• Provided valuable genetic insights and resources for improving rice yield through polyploidy.