May be involved in disease resistance. Strongly expressed in pollen grains (PubMed:16203714). Also present at weak levels in seedling roots, in sapling stems and in developing male strobili (PubMed:16203714). Weakly induced by abscisic acid (ABA). Causes an oral allergy syndrome (OAS) reaction in human and animals (PubMed:22749702, PubMed:26433527, PubMed:17441795). Binds to IgE and induces the release of histamine from leukocytes of allergic patients (PubMed:17441795). Binds to IgE from canine atopic dermatitis (CAD) sensitive dogs (PubMed:22749702). Belongs to the thaumatin family.