Establishment of SRLC: a multiplex genome editing technology for Saccharomyces cerevisiae and its application in metabolic engineering of malonyl-CoA pathway

The development of advanced genome engineering tools is crucial for optimizing metabolic pathways in Saccharomyces cerevisiae and achieving efficient biomanufacturing. This study proposes an enhancing multiplex genome editing strategy in S. cerevisiae by employing Escherichia coli-derived single-stranded annealing proteins (SSAPs) combined with S. cerevisiae-derived homologous recombinases (Rad51 and Rad52). The strategy utilizes an SSAP-Rad-Linearized CRISPR (SRLC) platform, which supports efficient simultaneous editing of multiple genomic loci without constructing complex multi-gRNA expression vectors. Co-overexpressing Rad51/Rad52 and E. coli SSAP proteins significantly enhances homologous recombination (HR), allowing precise multi-locus genome editing mediated by short homologous arms. Furthermore, SRLC employs a linearized CRISPR-Cas system to stimulate homologous recombination and enable counter-selection in S. cerevisiae, thereby improving precise multiplex genome editing efficiency. We applied SRLC to engineer the malonyl-CoA metabolic pathway in S. cerevisiae. Through a single round of editing and screening, we constructed a chassis strain with 9 targets simultaneously modification and achieved a 9.6-fold increase in intracellular malonyl-CoA. Using this chassis, 3-hydroxypropionic acid production increased 4.5-fold relative to wild-type S. cerevisiae. This platform offers a robust and scalable tool for S. cerevisiae manipulation and a practical pathway-engineering strategy for building for malonyl-CoA-derived factories.