A Multipurpose Toolkit to Enable Advanced Genome Engineering in Plants.

Area of Science:

• Plant Molecular Biology
• Genome Engineering
• Biotechnology

Background:

• Efficient and precise genome engineering tools are crucial for plant research and crop improvement.
• Existing methods often face limitations in multiplexing and efficiency for diverse plant species.

Purpose of the Study:

• To develop and validate a comprehensive toolkit for targeted genome modification in monocot and dicot plants.
• To enhance the efficiency and versatility of genome engineering through novel reagent design and delivery systems.

Main Methods:

• Utilized transcription activator-like effector nucleases (TALENs) and CRISPR/Cas9 systems with modular cloning vectors.
• Integrated geminivirus-based vectors for precise gene editing via homologous recombination.
• Employed Csy4 and tRNA processing enzymes for simultaneous expression of multiple guide RNAs (gRNAs), and Trex2 exonuclease for enhanced mutagenesis.

Main Results:

• Demonstrated efficient single or multiple gene knockouts and large chromosomal deletions.
• Achieved targeted deletions in up to six genes by expressing 12 gRNAs from a single transcript using Csy4/tRNA systems.
• Showcased enhanced mutagenesis (2.5-fold) with Trex2 exonuclease and comparable gene targeting frequencies with Cas9 nickases on geminivirus replicons.
• Validated the toolkit in tomato, tobacco, Medicago truncatula, wheat, and barley.

Conclusions:

• The developed toolkit provides a robust and efficient platform for diverse genome engineering applications in plants.
• The novel strategies for multiplexed gRNA expression and enhanced mutagenesis significantly improve genome editing efficiency.
• This resource facilitates accelerated functional genomics studies and crop trait development.