Generation of Two-Line Restorer Line with Low Chalkiness Using Knockout of <i>Chalk5</i> through CRISPR/Cas9 Editing
Gucheng Fan,
Jiefeng Jiang,
Yu Long,
Run Wang,
Famao Liang,
Haiyang Liu,
Junying Xu,
Xianjin Qiu,
Zhixin Li
Affiliations
Gucheng Fan
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, China
Jiefeng Jiang
Ningbo Academy of Agricultural Science, Ningbo 315101, China
Yu Long
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, China
Run Wang
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, China
Famao Liang
Yichang Academy of Agricultural Sciences, Yichang 443004, China
Haiyang Liu
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, China
Junying Xu
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, China
Xianjin Qiu
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, China
Zhixin Li
Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, College of Agriculture, Yangtze University, Jingzhou 434025, China
Chalkiness is an important grain quality trait in rice. Chalk5, encoding a vacuolar H+-translocating pyrophosphatase, is a major gene affecting both the percentage of grains with chalkiness (PGWC) and chalkiness degree (DEC) in rice. Reducing its expression can decrease both PGEC and DEC. In this study, the first exon of Chalk5 was edited in the elite restorer line 9311 using the CRISPR/Cas9 system and two knockout mutants were obtained, one of which did not contain the exogenous Cas9 cassette. PGWC and DEC were both significantly reduced in both mutants, while the seed setting ratio (SSR) was also significantly decreased. Staggered sowing experiments showed that the chalkiness of the mutants was insensitive to temperature during the grain-filling stage, and the head milled rice rate (HMRR) could be improved even under high-temperature conditions. Finally, in the hybrid background, the mutants showed significantly reduced PGWC and DEC without changes in other agronomic traits. The results provide important germplasm and allele resources for breeding high-yield rice varieties with superior quality, especially for high-yield indica hybrid rice varieties with superior quality in high-temperature conditions.
