Expression of tachyplesin gene in yeast Pichia pastoris

Tachyplesin gene was designed and chemically synthesized with codon usage bias. The stop codon TAG and some restriction sites convenient for further cloning were added to this gene. The synthesized gene cloned into yeast expression vector pPIC9 (with ex-secretion signal) was transformed into host strain GS115 by electroporation. The tachyplesin expressed from recombinants Y-PIC27 and Y-PIC42 showed an inhibition activity against the germination of the spores of Magnaporthe grisea. Southern blot performed with chromosome genome of the two recombinants indicated a single copy of the expression cassette was integrated at the chromosomal AOX1 locus by which the genomic AOX1 gene was functionally disrupted and Northern blot showed the presence of transcripts of the tachyplesin gene.