Fine-tuning quantitative agronomic traits by manipulating gene copy number in rice

Area of Science:

• Plant genetics
• Crop science
• Molecular biology

Background:

• Pan-genome studies reveal extensive copy number variations (CNVs) in plants.
• The phenotypic impact of CNVs on crucial agronomic traits is largely unknown.

Purpose of the Study:

• To investigate the phenotypic consequences of manipulating gene copy number in rice.
• To explore the potential of gene copy number manipulation as a crop improvement strategy.

Main Methods:

• Utilized CRISPR/Cas9 gene editing to create rice lines with varying OsMADS18 gene copy numbers (1-3 tandem copies).
• Employed quantitative PCR (qPCR) and sequencing for precise copy number determination.
• Assessed OsMADS18 transcript levels and associated agronomic traits.

Main Results:

• Successfully generated rice lines with one to three tandem copies of the OsMADS18 gene.
• Demonstrated a direct correlation between increased OsMADS18 copy number, elevated transcript levels, and enhanced agronomic trait values.
• Observed stepwise increases in quantitative traits corresponding to gene copy number increments.

Conclusions:

• Gene copy number is a critical factor influencing quantitative agronomic traits in rice.
• OsMADS18 copy number manipulation offers a viable strategy for fine-tuning crop performance.
• This approach presents a novel breeding method for enhancing crop improvement and yield potential.