Compositions and methods for helper strain-mediated fungal genome modification

A method for homologous recombination of a donor DNA with a genomic locus in a fungal cell, the method comprising:

• (a) generating a heterokaryon between a helper fungal strain and a target fungal strain, wherein the helper fungal strain comprises an expression construct that silences the non-homologous end joining (NHEJ) mechanism;
• (b) introducing a donor DNA into the heterokaryon, wherein the donor DNA comprises a region of homology to a genomic locus in the target strain sufficient for homologous recombination at the genomic locus;
• (c) generating and plating spores from the heterokaryon cells of (b);
• and,
• (d) identifying cells from the plated spores in which (i) the donor DNA has integrated into the genome by homologous recombination at the genomic locus, and (ii) the expression construct that silences the non-homologous end joining (NHEJ) mechanism is not present.