Phytopathology 96 (2), pp. 164-170
Genetics and Resistance
Cloning and Characterization of a Putative Antifungal Peptide Gene (Pm-AMP1) in Pinus monticola. A. K. M. Ekramoddoullah, J.-J. Liu, and A. Zamani. Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, B.C. V8Z 1M5 Canada. Phytopathology 96:164-170. Accepted for publication 21 September 2005. Copyright 2006 Her Majesty the Queen in right of Canada, Natural Resources Canada, Canadian Forest Service.
We have been working on proteins that are involved in the defense response of
western white pine (WWP) (Pinus monitcola) to the blister rust fungus
Cronartium ribicola. Our objective was to identify candidate genes that
could be used for improving resistance of WWP to this rust pathogen. During
proteomic analysis of bark proteins extracted from WWP trees exhibiting slow-canker-growth
(SCG) resistance, a 10.6-kDa peptide, termed Pm-AMP1, was found to be enriched
at the receding canker margin. The cDNA encoding this peptide was cloned and
characterized. A BLASTX search revealed that the Pm-AMP1 encoded by its cDNA has
a 50% homology with MiAMP1, a broad-spectrum antifungal protein isolated from
Macadamia integrifolia. Based on the deduced amino acid sequence, an
antibody was produced against the Pm-AMP1. Immunochemical quantification of the
Pm-AMP1 in bark samples of susceptible WWP trees revealed this protein to be
barely detectable in the cankered tissues, but occurring in higher
concentrations in healthy tissues away from canker margins. Foliage of SCG-resistant
trees contained higher concentrations of the Pm-AMP1 than foliage from
susceptible cankered trees. Both wounding and methyl jasmonate treatment of WWP
needles induced the expression of this protein, further supporting its putative
role as a defense response protein. Additional keywords: electrophoresis,
western immunoblot.