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A conditional marker gene allowing both positive and negative selection in plants.
Nature Biotechnology
|April 17, 2004
Summary
A novel marker gene, dao1, encoding D-amino acid oxidase (DAAO), offers versatile positive or negative selection in transgenic plants. This DAAO marker provides rapid, unambiguous results for plant transformation and selection.
Area of Science:
- Plant Biotechnology
- Molecular Biology
- Biochemistry
Background:
- Selectable markers are crucial for identifying transformed plant cells.
- Existing markers are typically categorized as positive (selective advantage) or negative (selective disadvantage).
Discussion:
- The D-amino acid oxidase (DAAO) gene (dao1) functions as a versatile selectable marker.
- DAAO metabolizes D-amino acids, with selection dependent on substrate toxicity and metabolite effects.
- This allows for both positive and negative selection strategies using a single marker gene.
Key Insights:
- D-alanine and D-serine are detoxified by DAAO, enabling positive selection.
- D-isoleucine and D-valine are converted to toxic keto acids by DAAO, facilitating negative selection.
- The dao1 marker gene has been successfully implemented in Arabidopsis thaliana.
Outlook:
- This versatile marker accelerates the selection process in plant transformation.
- Unambiguous results are obtained rapidly, even immediately after germination.
- Potential applications in crop improvement and genetic engineering research.