A birch gene family encoding pollen allergens and pathogenesis-related proteins.
Bet v I, the major pollen allergen of birch (Betula verrucosa), shows high sequence homology to a family of pathogenesis-related (PR) proteins that have recently been identified in several other plant species. We have used a pollen Bet v I cDNA clone and anti-Bet v I antibodies as probes to study the expression of Bet v I genes in birch cell suspension cultures under different experimental conditions. Induction of Bet v I-related proteins was detected in immunoblots of cell extracts upon co-cultivation with microbial pathogens. Northern analysis revealed the rapid induction of Bet v I transcripts in the presence of bacteria and fungi, but not by stress treatments (heat shock, metal ions) or by chemical elicitors. RNase protection experiments showed that the pathogen-inducible RNAs did not correspond to the pollen cDNA clone but most likely to the products of transcription of other members of the Bet v I gene family, sharing high sequence homology with the pollen-specific gene within the 5'-half of the coding region. We conclude that the Bet v I gene family of pollen allergens includes a subset of defense-related genes that are transcriptionally activated in the presence of microbial pathogens.
Swoboda
I
I
Institute of Microbiology and Genetics, University of Vienna, Vienna Biocenter, Austria.
Scheiner
O
O
Kraft
D
D
Breitenbach
M
M
Heberle-Bors
E
E
Vicente
O
O
D000485:Allergens / Q000235:genetics*; D052179:Antigens, Plant; D015870:Gene Expression; D017343:Genes, Plant; D005810:Multigene Family; D010940:Plant Proteins / Q000235:genetics*; D011058:Pollen; D012333:RNA, Messenger / Q000235:genetics; D014197:Trees / Q000235:genetics*
D000485:Allergens; D052179:Antigens, Plant; D010940:Plant Proteins; D012333:RNA, Messenger; C061312:Bet v 1 allergen, Betula