Pollen of common ragweed (Ambrosia artemisiifolia) is a main cause of allergic diseases in Northern America. The weed has recently become spreading as a neophyte in Europe, while climate change may also affect the growth of the plant and additionally may also influence pollen allergenicity. | Ragweed Ambrosia artemisiifolia pollen allergenicity SuperSAGE transcriptomic analysis upon elevated CO2 and drought stress