Related Experiment Video
Updated: Sep 18, 2025
In Vitro Directed Evolution of a Restriction Endonuclease with More Stringent Specificity
Published on: March 25, 2020
Engineering Adenine Deaminase TadA for Precise and PAM-Flexible Point Mutagenesis and Gradient-Tuning Endogenous
Kangli Sun1, Si Cheng2, Nan Chai3
1Rice Research Institute, Guangdong Academy of Agricultural Sciences, Key Laboratory of Genetics and Breeding of High-Quality Rice in Southern China (Co-construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Rice Science and Technology, Guangdong Rice Engineering Laboratory, Guangzhou, 510640, China.
Engineered base editors achieve precise dual-base editing (A-to-G and C-to-T) with a PAM-flexible SpRY nickase. This technology enables gradient-tuned agronomic traits in plants, such as rice, by modifying key genes like OsBadh2.
Area of Science:
- Molecular Biology
- Plant Biotechnology
- Genome Editing
Background:
- Base editing offers precise nucleotide substitutions but suffers from bystander editing, limiting accuracy.
- Point mutagenesis is crucial for fine-tuning protein function and generating diverse plant phenotypes for various environmental and consumer needs.
Purpose of the Study:
- To engineer novel plant base editors with enhanced precision and PAM flexibility.
- To develop a dual-base editor capable of simultaneous A-to-G and C-to-T conversions.
- To apply these editors for targeted mutagenesis in rice to modulate key agronomic traits.
Main Methods:
- Fusion of optimized TadA variants (TadA9, TadA-LM, TadA-dual) with a PAM-flexible SpRY nickase (SpRYn).
- Development of the TadA Dual-Base Editor (TadDBE) for A-to-G and C-to-T conversions within a 1-3 nucleotide window.
- Application of TadDBE for point mutagenesis of the OsBadh2 gene in rice.
Main Results:
- Engineered base editors demonstrated A-to-G, C-to-T, and dual-base conversions with a condensed active window.
- The TadDBE achieved robust dual-base editing efficiencies (2.3%–61.4%) with minimal off-target effects.
- Mutagenesis of OsBadh2 using TadDBE generated rice lines with gradient-tuned aromatic profiles and altered 2-AP and GABA levels.
Conclusions:
- The developed TadA-derived editors provide a precise and PAM-flexible platform for base editing in plants.
- This technology offers a versatile strategy for generating genome-edited plants with tailored agronomic traits.
- The engineered base editors significantly improve accuracy and efficiency compared to existing methods.
