A spruce defensin showing strong antifungal activity and increased transcript accumulation after wounding and jasmonate treatments

In this work, a cDNA encoding a defensin from Picea glauca, named PgD1, was isolated. The corresponding PgD1 DNA encodes a putative protein of 83 amino acids with a calculated molecular mass of 8.9 kDa. The mature protein of 50 amino acids is characterized by the presence of specific highly conserved residues common to all plant defensins. PgD1 is developmentally expressed during seed germination and is also up-regulated by wounding and by jasmonic acid treatment, suggesting a role in both the constitutive and induced defense mechanisms. The recombinant protein was found to cause extensive growth inhibition of three fungal pathogens (Cyclindrocladium floridanum, Fusarium oxysporum and Nectria galligena) at 2.5 muM. Crown Copyright (C) 2004 Published by Elsevier Ltd. All rights reserved.