Efficient CRISPR-Cas genome editing in brown algae

Area of Science:

• Marine Biology
• Evolutionary Biology
• Genetics

Background:

• Brown algae are a unique lineage of complex multicellular organisms, distinct from plants and animals.
• Functional studies in brown algae have been hindered by a lack of efficient genome editing tools.

Purpose of the Study:

• To develop a robust, high-efficiency, and transgene-free CRISPR-based genome editing platform for brown algae.
• To enable functional genomics research in ecologically and biotechnologically important brown algal species.

Main Methods:

• Optimized a polyethylene glycol (PEG)-mediated ribonucleoprotein (RNP) delivery system in Ectocarpus.
• Demonstrated precise editing of the IMMEDIATEUPRIGHT (IMM) locus to recreate a known mutant phenotype.
• Utilized APT/2-fluoroadenine (2-FA) selection to enhance editing specificity.

Main Results:

• Achieved reproducible, transgene-free genome editing across multiple loci without specialized equipment.
• Successfully recreated the imm mutant phenotype, validating the platform's efficacy.
• Demonstrated the platform's transferability to other brown algal species, including kelps.

Conclusions:

• The developed CRISPR platform provides a powerful new tool for functional genomics in brown algae.
• This advancement will facilitate research into brown algal development, life cycle regulation, and the evolution of multicellularity.
• Enables deeper investigation into the independent evolution of complex traits in brown algae.