CRISPR/Cas9-mediated gene targeting in Arabidopsis using sequential transformation

Area of Science:

• Plant biotechnology
• Molecular biology
• Genetics

Background:

• Homologous recombination (HR)-based gene targeting is crucial for precise genome editing.
• Gene targeting in plants, especially the model plant Arabidopsis thaliana, faces significant challenges.
• Existing methods lack efficiency for routine genetic manipulation in plants.

Purpose of the Study:

• To develop an improved method for gene targeting in Arabidopsis thaliana.
• To enhance the efficiency and reliability of homologous recombination-mediated genome modification in plants.
• To enable routine and precise genetic manipulation in the Arabidopsis thaliana model system.

Main Methods:

• A sequential transformation method was employed for gene targeting in Arabidopsis.
• Parental lines expressing the bacterial Cas9 endonuclease under an egg cell- and early embryo-specific promoter (DD45) were generated.
• Single-guide RNA (sgRNA)-directed homologous recombination was utilized for gene knock-ins and sequence replacements at endogenous loci.

Main Results:

• The Cas9-DD45 promoter system significantly improved the frequency of gene knock-ins and sequence replacements via homologous recombination.
• Heritable gene targeting events were successfully achieved at multiple endogenous sites in the Arabidopsis genome.
• Targeted modifications were readily identifiable using standard Polymerase Chain Reaction (PCR) techniques.

Conclusions:

• The developed sequential transformation method enhances gene targeting efficiency in Arabidopsis.
• Utilizing Cas9 under tissue-specific promoters facilitates precise and heritable genome modifications.
• This approach establishes a robust platform for routine genetic engineering in Arabidopsis thaliana.