The GW5-WRKY53-SGW5 module regulates grain size variation in rice

Area of Science:

• Plant genetics
• Molecular biology
• Agronomy

Background:

• Grain size is a critical factor influencing rice yield, quality, and domestication.
• Understanding the genetic regulation of grain size is essential for crop improvement.

Purpose of the Study:

• To identify novel quantitative trait genes (QTGs) controlling natural variation in rice grain size.
• To elucidate the molecular mechanisms and genetic interactions underlying grain size regulation.

Main Methods:

• Map-based cloning was employed to identify the novel QTG SGW5.
• Analysis of gene expression, near-isogenic lines, and gene knockout was performed.
• Investigated cis-element variation and transcription factor interactions.

Main Results:

• SGW5 was identified as a positive regulator of grain width, affecting cell division and size in spikelet hulls.
• Differential SGW5 expression in near-isogenic lines led to a 12.2% increase in grain yield.
• A cis-element variation in the SGW5 promoter impacts WRKY53 binding, causing differential gene expression and grain size variation.
• GW5 interacts with WRKY53 to suppress SGW5 expression.

Conclusions:

• A novel regulatory pathway, the GW5-WRKY53-SGW5 module, controlling rice grain size was elucidated.
• This study provides insights into QTG interactions and genetic diversity for important crop traits.