A gene-targeting system in Trichosporon asahii JCM2466 by Agrobacterium tumefaciens-mediated transformation

Abstract Trichosporon asahii is a pathogenic fungus that causes severe, deep-seated fungal infections in neutropenic patients. The complete genome information of T. asahii JCM2466 (CBS2479), a standard type strain widely used in research, is publicly available, but a gene-targeting system for T. asahii JCM2466 has not yet been developed. Here we generated gene-deficient mutants of T. asahii JCM2466 by Agrobacterium tumefaciens-mediated transformation (ATMT). A gene-deficient mutant lacking the ku70 gene, which encodes the Ku70 protein involved in non-homologous end-joining repair of DNA double-strand breaks, was generated by ATMT. The ku70 gene-deficient mutant exhibited higher gene-targeting efficiency than the wild-type strain for generating a mutant lacking the cnb1 gene, which encodes the beta-subunit of calcineurin. In the ku70 gene-deficient mutant used as a parent strain, cnb1 gene-deficient mutants were generated by ATMT. The cnb1 gene-deficient mutants exhibited sensitivities to high temperature and several stress-inducing compounds. These results suggest that the combination of the ku70 gene-deficient mutant and ATMT is a useful method for generating gene-deficient mutants of T. asahii JCM2466.