Abstract:
【Objective】 To screen
sgRNAs with high targeted mutagenesis for specific genes in cotton by designing vectors carrying
sgRNA expressing cassettes based on TRV virus delivery system to rapidly detect editing efficiency.
【Methods】 The
sgRNA cassettes were assembled into the TRV viral vector using the infusion reaction, transiently expressed in
Cas9-
OE transgenic cotton leaves. Mutageneses for targeted genes were verified by RE-PCR and Sanger sequencing.
【Results】 Different
sgRNA delivery systems carrying cotton
CLA1 and
COR27 gene targeted
sgRNA respectively were expressed in
Cas9-
OE transgenic cotton, and results indicated the frequency of mutations reached more than 65% for all the four systems. All plants showed mutations in the gene with nucleotide deletions being more frequent than insertions or replacements. The editing frequency of delivery system driven by GhU6 promoter was higher (80% or more) than that driven by AtU6 promoter (60%-70%). Moreover, delivery systems with tRNA-gRNA-tRNA (PTG) cassette had slightly higher editing efficiency than those of the other delivery systems.
【Conclusion】 TRV virus-mediated
sgRNA delivery systems are functional for gene editing in cotton and act as tools for highly efficient detection of mutations induced by targeted gene
sgRNA. The TRV-GhU6:: PTG-
sgRNA delivery system has more utility value than others as a tool for high-throughput screening of targeted gene
sgRNA.