Rice Research Institute,Guangdong Academy of Agricultural Sciences / Guangdong Key Laboratory of New Technology in Rice Breeding / Guangdong Rice Engineering Laboratory
The Investment Project of Department of Agriculture and Rural Affairs,Development and Reform Commission,Guangdong Province(2021),No.272，Agricultural Competitive Industry Discipline Team Building Project of Guangdong Academy of Agricultural Sciences (202101TD)，Research and Development Program in Key Areas of Guangdong Province (2020B0202090003)，Guangdong Provincial Natural Science Foundation (2019A1515011208, 2021A1515011226)，Project of Guangdong Key Laboratory (2020B1212060047)
Wx gene directly controls the synthesis of amylose in rice endosperm，and thus affects many cooking quality traits such as gel consistency，which is the major gene controlling the eating quality of rice. It can significantly improve the rice eating quality by moderately reducing amylose content（AC）. Jifeng B（JB） is a maintainer line of indica hybrid rice with high AC，which reduces the eating quality of the progeny. CRISPR/ Cas9 technology has been applied more and more in rice molecular breeding. In this study，four target sites were selected from the upstream sequence of coding region of Wx gene，and the editing vector was constructed and introduced into JB by Agrobacterium tumefaciens. A total of 9 transgenic lines，L1-L9，were obtained. Among them，L8 and L9 had a large fragment deletion mutation，in which the expression of Wx gene and AC were downregulated. The gel consistency and eating quality were also improved. There is a great difference in the appearance of brown rice between L8 and L9. L8 is similar to glutinous rice and L9 is similar to sticky rice. To sum up，we used CRISPR/Cas9 technology to edit the upstream untranslated region of Wx gene in order to reduce the AC in rice，and achieved success. These results provide a reference for the study of rice quality improvement.