Creation of Waxy allelic mutants of the rice Waxy gene using CRISPR/Cas9 technology
In this study,CRISPR/Cas9 gene editing technology was used to design four knockout targets located in the promoter region,5'UTR region and exons 2 and 3 of the granule bound starch synthase gene(Waxy,Wx)in the japonica rice variety"Jiahua 1".We then obtained four different types of T1 generation homozygous edited-mutants without transgene to investigate their quality and agronomic traits.Compared to the wild type"Jiahua 1",the amylose content(AC)of the wxpro mutants in the promoter region decreased to 14.09%,while the wxutr mutants in the 5'UTR region decreased to 11.76%,with a loose arrangement of starch grains.The wxex2 and wxex3 mutants in the exon regions had an AC of to less than 2%,similar to that of glutinous rice.In summary,all stable-inherited homozygous wx mutants,with varying AC,not only enrich the Wx allelic mutant genes in rice,but also provide valuable genetic and breeding materials for improving rice eating quality.