A research team led by Dr. LI Yunhai from Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences has uncovered a novel genetic mechanism that controls grain size and yield in rice, offering promising strategies to enhance global food production.
Published in
PNAS (
https://doi.org/10.1073/pnas.2419464122) by a collaborative team from Chinese Academy of Sciences and Hainan University, the research reveals how three critical components—OsMED23, OsJMJ703, and OsWOX3A—work together to influence rice grain development.
The Genetic Trio Behind Bigger Grains
Grain size is a major factor determining crop yield, yet the molecular pathways regulating it remain poorly understood. The team discovered that OsMED23, a component of the cellular “Mediator” complex that helps regulate gene activity, partners with a histone demethylase (OsJMJ703) and a transcription factor (OsWOX3A) to form a molecular trio. This trio acts as a repressor, dialing down the activity of two key genes, GW2 and OsLAC, which are known to limit grain growth. By reducing levels of a specific epigenetic marker (H3K4me3) at these genes, the trio effectively silences them, allowing grains to grow larger and heavier.
From Lab to Field: Boosting Yield
Experiments showed that disabling OsMED23 or OsJMJ703 led to smaller and lighter grains, while overexpressing these genes produced the opposite effect—plumper, heavier grains. Field trials confirmed the practical impact: rice plants with extra OsMED23 or OsJMJ703 delivered significantly higher yields compared to conventional varieties. This highlights the trio’s potential as a genetic lever for crop improvement.
A New Path for Crop Engineering
The discovery bridges a critical gap in our understanding of how epigenetic regulation and transcription factors collaborate to shape grain traits. Unlike previous studies focusing on individual genes, this work reveals a coordinated network, offering multiple targets for precision breeding.
Implications Beyond Rice
While the study focused on rice, the mechanism may apply to other staple crops like wheat and maize, which share similar homologs. The findings also underscore the untapped potential of epigenetic editing—adjusting chemical markers on DNA—to fine-tune crop traits.
In summary, this research not only solves a long-standing puzzle in plant biology but also opens doors to smarter and sustainable farming. By harnessing the power of OsMED23, OsJMJ703 and OsWOX3A, scientists are one step closer to breeding crops that feed more people with fewer resources.
The Mediator subunit OsJMJ703-OsMED23-OsWOX3A controls grain size and yield in rice. (Image by IGDB)
Contact:
Dr. LI Yunhai
Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences
Email: yhli@genetics.ac.cn
CAS
中文
.png)
