OsSPL18 controls grain weight and grain number in rice

Area of Science:

• Plant Biology
• Genetics
• Agricultural Science

Background:

• Grain yield in rice is determined by grain weight and grain number.
• The regulatory mechanisms governing these crucial traits are not fully understood.
• OsSPL18's role in rice development requires further investigation.

Purpose of the Study:

• To elucidate the biological function of OsSPL18 in rice grain and panicle development.
• To identify the molecular mechanisms through which OsSPL18 influences yield-related traits.
• To uncover novel regulatory pathways impacting rice yield.

Main Methods:

• Gene knockout (KO) of OsSPL18 and phenotypic analysis.
• Cytological analysis of spikelet hull development.
• Gene expression analysis using qRT-PCR and GUS staining.
• Transcription factor activity assays and promoter binding studies (yeast one-hybrid, dual-luciferase).
• RNA analysis (5' RLM-RACE) to investigate microRNA interactions.

Main Results:

• OsSPL18 KO mutants showed reduced grain size, panicle length, and grain number, with increased tillers.
• OsSPL18 regulates spikelet hull development by influencing cell proliferation.
• OsSPL18 acts as a transcription factor, positively regulating DEP1 expression.
• OsSPL18 is targeted by OsmiR156k, indicating a microRNA-mediated regulatory mechanism.

Conclusions:

• A novel OsmiR156k-OsSPL18-DEP1 regulatory pathway controlling rice grain number has been identified.
• OsSPL18 plays a critical role in rice yield by modulating grain number and panicle development.
• Understanding this pathway offers potential targets for improving rice breeding strategies.