Base Editors for Citrus Gene Editing

Area of Science:

• Plant Biotechnology
• Genome Editing
• Citrus Genetics

Background:

• Base editors offer precise genome editing without double-strand breaks, mitigating risks of genome instability.
• Previous precise gene editing in citrus using base editors had not been reported.
• Citrus canker and herbicide resistance are significant agricultural challenges.

Purpose of the Study:

• To adapt adenine base editors (ABE) and cytosine base editors (CBE) for precise gene editing in citrus species.
• To generate citrus plants resistant to citrus canker and herbicides using base editors.
• To develop transgene-free gene-edited citrus using CRISPR technology.

Main Methods:

• Adenine base editors (ABE) were used to modify the TATA box in the LOB1 promoter of grapefruit and sweet orange.
• Cytosine base editors (CBE) were employed to edit the acetolactate synthase (ALS) gene in citrus.
• CRISPR technology was utilized for gene editing, with subsequent analysis for transgene presence.

Main Results:

• ABE successfully edited the LOB1 promoter, conferring resistance to citrus canker pathogen Xanthomonas citri subsp. citri (Xcc).
• CBE successfully edited the ALS gene, resulting in herbicide resistance to chlorsulfuron.
• The ALS-edited citrus plants were confirmed to be transgene-free, marking a significant advancement in CRISPR technology application.

Conclusions:

• Base editors (ABE and CBE) are effectively adapted for precise genome editing in citrus.
• Gene-edited citrus plants exhibit enhanced resistance to diseases and herbicides.
• The development of transgene-free gene-edited citrus represents a breakthrough for agricultural applications.