With rapid progress in DNA synthesis and sequencing, strain engineering starts to be the rate-limiting step in synthetic biology. Here, we report a gRNA-tRNA array for CRISPR-Cas9 (GTR-CRISPR) for multiplexed engineering of Saccharomyces cerevisiae . Using reported gRNAs shown to be effective, this system enables simultaneous disruption of 8 genes with 87% efficiency. We further report an accelerated Lightning GTR-CRISPR that avoids the cloning step in Escherichia coli by directly transforming the Golden Gate reaction mix to yeast. This approach enables disruption of 6 genes in 3 days with 60% efficiency using reported gRNAs and 23% using un-optimized gRNAs. Moreover, we applied the Lightning GTR-CRISPR to simplify yeast lipid networks, resulting in a 30-fold increase in free fatty acid production in 10 days using just two-round deletions of eight previously identified genes. The GTR-CRISPR should be an invaluable addition to the toolbox of synthetic biology and automation.

Targeted genome disruptions and single-nucleotide conversions with the CRISPR/Cas system have greatly facilitated the development of gene therapy, basic biological research, and synthetic biology. With vast progress in this field, there are still aspects to be optimized, including the target range, the ability to multiplex, the mutation efficiency and specificity, as well as the requirement of adjusting protospacer adjacent motifs (PAMs). Here, we report the development of a highly efficient genome disruption and single-nucleotide conversion tool with a gRNA-tRNA array and SpCas9-NG (GTR 2.0). We performed gene disruptions in yeast cells covering all 16 possible NGN PAMs and all 12 possible single-nucleotide conversions (N to N) with near 100% efficiencies. Moreover, we applied GTR 2.0 for multiplexed single-nucleotide conversions, resulting in 66.67% mutation efficiency in simultaneous generation of 4 single-nucleotide conversions in one gene, as well as 100% mutation efficiency for simultaneously generating 2 single-nucleotide conversions in two different genes. GTR 2.0 will substantially expand the scope, efficiency, and capabilities of yeast genome editing, and will be a versatile and invaluable addition to the toolbox of synthetic biology and metabolic engineering.