Multiplex genomic edition in Ashbya gossypii using CRISPR-Cpf1

The CRISPR/Cas technologies constitute an essential tool for rapid genome engineering of many organisms, including fungi. The CRISPR/Cas9 system adapted for the industrial fungus Ashbya gossypii enables the efficient genome editing for the introduction of deletions, insertions and nucleotide substitutions. However, the Cas9 system is constrained to the existence of an specific 5-NGG-3 PAM sequence in the target site.\n\nHere we present a new CRISPR/Cas system for A. gossypii that expands the molecular toolbox available for microbial engineering of this fungus. The use of Cpf1 nuclease from Lachnospiraceae bacterium allows to employ a T-rich PAM sequence (5-TTTN-3) and facilitates the implementation of a multiplexing CRISPR/Cpf1 system adapted for A. gossypii. The system has been validated for the introduction of large deletions into five different auxotrophic marker genes (HIS3, ADE2, TRP1, LEU2 and URA3). The use of both crRNA and dDNA arrays in a multi-CRISPR/Cpf1 system was demonstrated to be an efficient strategy for multiplex gene deletion of up to four genes using a single multi-CRISPR/Cpf1 plasmid. Our results also suggest that the selection of the target sequence may significantly affect to the edition efficiency of the system.