摘要
Cytosine and adenosine base editors(CBEs and ABEs)are novel genome-editing tools that have been widely utilized in molecular breeding to precisely modify single-nucleotide polymorphisms(SNPs)critical for plant agronomic traits and species evolution.However,conventional BE editors are limited to achieve C-to-T and A-to-G substitutions,respectively.To enhance the applicability of base editing technology in watermelon,we developed an efficient CGBE editor(SCGBE2.0)by removing the uracil glycosylase inhibitor(UGI)unit from the commonly used hA3A-CBE and incorporating the uracil-DNA glycosylase(UNG)component.Seven specific guide RNAs(sgRNAs)targeting five watermelon genes were designed to assess the editing efficiency of SCGBE.The results obtained from stably transformed watermelon plants demonstrated that SCGBE2.0 could efficiently induce C-to-G mutations at positions C5–C9 in 43.2%transgenic plants(with a maximum base conversion efficiency of 46.1%)and C-to-A mutation at position C4 in 23.5%transgenic plants(with a maximum base conversion efficiency of 45.9%).These findings highlight the capability of our integrated SCGBE2.0 editor to achieve C-to-G/A mutations in a site-preferred manner,thus providing an efficient base editing tool for precise base modification and site-directed saturated mutagenesis in watermelon.
基金
supported by the National Youth Talent Program(A279021801)
Earmarked Fund for China Agriculture Research System(CARS-25)
Key-Area R&D Program of Guangdong Province(2022B0202060001)
Key R&D Program of Shaanxi province(2023-YBNY-008)
the Natural Science Foundation of Shaanxi Province(2022JM-112)
the Fundamental Research Funds for the Central Universities(2452022111)
the Science and Technology Innovation Team of Shaanxi(2021TD-32).
