Two members of the Bet v 1 gene family encoding birch pathogenesis-related proteins display different patterns of root expression and wound-inducibility

Abstract

Bet v 1-SC genes constitute a subset of a multigene family in birch (Betula pendula Roth) that includes the gene for the major pollen allergen and encode proteins belonging to a new family of intracellular pathogenesis-related proteins. We have investigated the expression in birch roots of the Bet v 1-SC1 and Bet v 1-SC3 genes by northern and reverse-transcription-polymerase chain reaction analyses. Only Bet v 1-SC3 was found to be highly expressed in roots under basal conditions but this gene was not wound-inducible. Conversely the expression of the Bet v 1-SC1 gene was markedly transiently induced 8 to 9 h after the stress. Immunoblotting with polyclonal antiserum raised against the major birch pollen allergen confirmed that Bet v 1-related polypeptides are present in root extracts. This first report of Bet v 1-SC gene expression and wound-inducibility in birch roots suggests a possible function of proteins encoded by these genes in plant defense and/or root organogenesis.