Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/18/2006
Publication Date: 7/7/2006
Citation: Janisiewicz, W.J., Pereira, I.B., Almeida, M.S., Roberts, D.P., Wisniewski, M.E., Kurtenbach, E. 2006. Biocontrol activity of recombinant Pichia pastoris constitutively expressing pea defensin against blue mold of apple. Phytopathology. 96:S53. Interpretive Summary:
Technical Abstract: A peptide (Psd1) isolated from pea seeds has been shown to have strong antifungal activity against a variety of fungi. The gene for this peptide was identified, and a recombinant peptide (46 residues) with activity similar to the original one was produced. We used a binary vector pGAPZalphaC containing this gene under a constitutive GAP promoter to transform Pichia pastoris strains X 33 and GS 115. Both strains transformed well and expressed the rPsd1 peptide. Untransformed strain X 33 grew better than GS 115 in Golden Delicious apple wounds, so biocontrol tests focused on X 33 transformants. The incidence of blue mold decay caused by Penicillium expansum on apples treated with the fungus alone or in combination with the parent strain, a transformant with the empty pGAPZaC vector or a transformant with the plasmid containing rPsd1 gene was 100%, 56%, 33%, and 11%, respectively, after 5 days incubation at 24 C. The consistency of this control still must be established.