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

## TL;DR

Scientists used gene editing to create small-grained rice with better quality, including less chalkiness and more protein, without affecting plant growth.

## Contribution

A novel method for breeding high-quality small-grained rice by targeting the OsVIN2 gene with CRISPR/Cas9.

## Key findings

- Editing OsVIN2 reduced grain size by 19.9% in length and 15.2% in width.
- The edited rice showed 11.0% higher protein and 77.5% less chalkiness.
- Plant growth and seed-setting were unaffected by the gene modification.

## Abstract

Small-grained rice is valuable for hybrid seed production and food markets, but developing high-quality small-grained varieties is challenging. This study aimed to use the CRISPR/Cas9 gene-editing technique to modify the OsVIN2 gene in rice variety MH86, hoping to reduce grain size while improving quality. We successfully edited OsVIN2, resulting in rice grains that were shorter and narrower than normal. The edited rice also had better quality: less chalkiness, more protein (11.0%), and optimized cooking texture. Importantly, other plant traits like growth and seed-setting remained unaffected. This method provides an effective way to breed high-quality small-grained rice, which can lower hybrid seed production costs and meet consumer demand for better-tasting rice.

Small-grained rice varieties are highly valued in hybrid seed production and food markets because of their unique advantages in mechanized seed production and cooking qualities. Developing new varieties combining small grain size with high nutritional and cooking quality represents an important breeding objective. The OsVIN2 gene has been identified as a key regulator involved in carbohydrate metabolism and grain development in rice. In this study, a CRISPR/Cas9-mediated gene-editing approach was employed to precisely modify the OsVIN2 gene in the restorer line MH86 of high-quality rice varieties. Compared with the wild-type plants, the frameshift mutant seeds showed a significant reduction in length and width by 19.9% and 15.2%, respectively, leading to a 39.2% decrease in thousand-grain weight. Notably, the mutant exhibited improved quality traits, including a decrease of 16.6% in amylose content, an increase of 11.0% protein, and a 77.5% and 84.7% decrease in chalkiness rate and chalkiness degree, respectively. These results demonstrate that targeted editing of OsVIN2 is a promising approach for creating novel small-grained rice germplasm with superior quality attributes.