Isolation and expression of an allergen-like mRNA from ethylene-treated Sambucus nigra leaflet abscission zones

revealed closest homology to a group of peptides related to A novel mRNA (Sn20) was isolated from Sambucus nigra the major pollen allergen from olive tree Olee1 ( Valenta et (elder) leaflet abscission zone cells. The transcript specifically al., 1996). Although the overall pairwise sequence similarity accumulates in abscission zone tissue after exposure to ethy- to the pollen allergens ranged from 30‐55%, alignment of lene (10 m ll ’1) for 18 h. The putative peptide encoded by Sn20 the Sn20 protein with Olee1 homologues showed a consensus shows close homology with the Olee1 pollen allergens. A sequence of 12 amino acids ( VYCDTCRAGFET ). In addipossible role for this protein in cell wall loosening is discussed. tion, certain cysteine residues are highly conserved both