Disclosed is a new technology that enables the transgenic modification of a mushroom-forming fungus to confer a transgenic genotype and/or phenotype. According to the invention herein, one can manipulate the fruiting body of a fungus conferring an altered phenotype, but a wild-type genotype. The fruiting body itself is devoid of any cognate transgene, and Applicants have discovered a new mechanism of protein synthesis and accumulation in fungi and a technique to independently control the genotype and phenotype of the fruiting body.