OsSPL13 controls grain size in cultivated rice

Area of Science:

• Plant genetics
• Agricultural science
• Molecular biology

Background:

• Genetic diversity is crucial for crop domestication.
• Natural variations in the rice genome influencing agronomic traits remain underexplored.
• Understanding these variations can improve rice breeding and yield.

Purpose of the Study:

• To identify genes controlling rice grain size using a diverse population.
• To functionally characterize the genetic basis of grain size variation.
• To explore the evolutionary history of important rice alleles.

Main Methods:

• Genome-wide association testing (GWAS) on a diverse rice population.
• Functional analysis of candidate genes related to grain size.
• Analysis of gene expression and regulatory elements (5' UTR tandem repeat).
• Introgression analysis to trace allele origins.

Main Results:

• A major quantitative trait locus, GLW7, encoding OsSPL13, was identified.
• OsSPL13 positively regulates grain hull cell size, increasing grain length and yield.
• A tandem repeat in the 5' UTR of OsSPL13 affects its expression.
• High OsSPL13 expression correlates with large grains in tropical japonica rice.
• The large-grain allele of GLW7 in tropical japonica rice originated from indica varieties via artificial selection.

Conclusions:

• New genes controlling important traits can be discovered using GWAS.
• OsSPL13 is a key regulator of rice grain size and yield.
• Artificial selection played a role in domesticating large-grain traits in rice.