Increased Agrobacterium‐mediated transformation of Saccharomyces cerevisiae after deletion of the yeast ADA2 gene

Agrobacterium tumefaciens is the causative agent of crown gall disease and is widely used as a vector to create transgenic plants. Under laboratory conditions, the yeast Saccharomyces cerevisiae and other yeasts and fungi can also be transformed, and Agrobacterium‐mediated transformation (AMT) is now considered the method of choice for genetic transformation of many fungi. Unlike plants, in S. cerevisiae, T‐DNA is integrated preferentially by homologous recombination and integration by non‐homologous recombination is very inefficient. Here we report that upon deletion of ADA2, encoding a component of the ADA and SAGA transcriptional adaptor/histone acetyltransferase complexes, the efficiency of AMT significantly increased regardless of whether integration of T‐DNA was mediated by homologous or non‐homologous recombination. This correlates with an increase in double‐strand DNA breaks, the putative entry sites for T‐DNA, in the genome of the ada2Δ deletion mutant, as visualized by the number of Rad52‐GFP foci. Our observations may be useful to enhance the transformation of species that are difficult to transform.