[Secretory expression of an antifungal protein in the mold Trichoderma viride].

AFP (antifungal protein) secreted by the filamentous fungi Aspergillus giganteus MDH18894 is a strong basic protein (pI>10.65). Its mRNA has an 430 bp open reading frame encoding the 94 amino acids' precursor of AFP. The precursor of AFP is processed to form the mature AFP of 51 amino acids by a putative two-step processing. A 285 bp AFP-like gene (i.e. AFP cDNA) lacking introns was reported to exist in the genome of Trichoderma viride, another species of filamentous fungi, but the gene was silent. In order to investigate whether the genomic AFP gene from A. giganteus could be expressed in T. viride, an expression plasmid with the open reading frame of AFP gene fused between the promoter and terminator of trpC gene was constructed and was transformed into T. viride. SDS-PAGE and Western blot analysis showed that AFP was expressed and secreted into the culture supernatant of the transformant of T. viride. Our study provides a basis for further secretory expression of heterologous eukaryotic genes of important value in the system of T. viride.