Generation of Novel High-Quality Small-Grained Rice Germplasm by Targeting the OsVIN2 Gene

Area of Science:

• Plant genetics
• Crop science
• Molecular biology

Background:

• Small-grained rice is crucial for mechanized production and desirable cooking qualities.
• Developing new rice varieties with small grains and enhanced nutritional/cooking traits is a key breeding goal.
• The OsVIN2 gene regulates carbohydrate metabolism and grain development in rice.

Purpose of the Study:

• To investigate the function of the OsVIN2 gene in rice grain characteristics.
• To utilize CRISPR/Cas9 gene editing to modify OsVIN2 in a high-quality rice restorer line (MH86).
• To assess the impact of OsVIN2 modification on grain size, weight, and quality attributes.

Main Methods:

• CRISPR/Cas9 gene editing was used to create frameshift mutations in the OsVIN2 gene.
• Quantitative analysis of seed dimensions (length, width), thousand-grain weight, amylose content, protein content, and chalkiness.
• Comparison of mutant lines with wild-type plants.

Main Results:

• Mutant seeds exhibited significantly reduced length (19.9%) and width (15.2%), decreasing thousand-grain weight by 39.2%.
• Improved quality traits were observed, including 16.6% less amylose, 11.0% more protein, and substantial reductions in chalkiness rate (77.5%) and degree (84.7%).
• Targeted OsVIN2 editing effectively altered grain morphology and quality.

Conclusions:

• Targeted editing of the OsVIN2 gene is an effective strategy for developing novel rice germplasm.
• This approach can yield small-grained rice varieties with superior nutritional and cooking qualities.
• OsVIN2 is a key target for breeding improved rice varieties for both production and consumption.