title: Ragweed (Ambrosia artemisiifolia) pollen allergenicity: SuperSAGE transcriptomic analysis upon elevated CO2 and drought stress.
abstract: BACKGROUND
  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. To gain better insight in the molecular mechanisms in the development of ragweed pollen and its allergenic proteins under global change scenarios, we generated SuperSAGE libraries to identify differentially expressed transcripts.
  
  
  RESULTS
  Ragweed plants were grown in a greenhouse under 380 ppm CO2 and under elevated level of CO2 (700 ppm). In addition, drought experiments under both CO2 concentrations were performed. The pollen viability was not altered under elevated CO2, whereas drought stress decreased its viability. Increased levels of individual flavonoid metabolites were found under elevated CO2 and/or drought. Total RNA was isolated from ragweed pollen, exposed to the four mentioned scenarios and four SuperSAGE libraries were constructed. The library dataset included 236,942 unique sequences, showing overlapping as well as clear differently expressed sequence tags (ESTs). The analysis targeted ESTs known in Ambrosia, as well as in pollen of other plants. Among the identified ESTs, those encoding allergenic ragweed proteins (Amb a) increased under elevated CO2 and drought stress. In addition, ESTs encoding allergenic proteins in other plants were also identified.
  
  
  CONCLUSIONS
  The analysis of changes in the transcriptome of ragweed pollen upon CO2 and drought stress using SuperSAGE indicates that under global change scenarios the pollen transcriptome was altered, and impacts the allergenic potential of ragweed pollen.
authors: Amr
authors: A
authors: El Kelish
authors: Feng
authors: F
authors: Zhao
authors: Werner
authors: W
authors: Heller
authors: Jörg
authors: J
authors: Durner
authors: J Barbro
authors: JB
authors: Winkler
authors: Heidrun
authors: H
authors: Behrendt
authors: Claudia
authors: C
authors: Traidl-Hoffmann
authors: Ralf
authors: R
authors: Horres
authors: Matthias
authors: M
authors: Pfeifer
authors: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany. ulrike.frank@helmholtz-muenchen.de.
authors: Ulrike
authors: U
authors: Frank
authors: Dieter
authors: D
authors: Ernst
mesh_terms: D000485:Allergens / Q000276:immunology*; D031164:Ambrosia / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D002245:Carbon Dioxide / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D030541:Databases, Genetic; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D055864:Droughts; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D015723:Gene Library; D011058:Pollen / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D064210:Secondary Metabolism / Q000187:drug effects; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D014022:Tissue Survival / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D000485:Allergens; D012333:RNA, Messenger; D002245:Carbon Dioxide