Inducing male flowering by applying gibberellic acid has no effect on the Cry j 1 content in Cryptomeria japonica pollen

摘要

Cryptomeria japonica pollinosis has recently become a serious problem in Japan. Two major allergens of C. japonica pollinosis, Cry j 1 and Cry j 2, have been isolated and characterized. Cry j 1 and Cry j 2 are basic proteins with molecular weights of 41-46 kDa and 37 kDa, respectively, and it was reported that more than 90% of C. japonica pollinosis patients had IgE specific to both of them. Several studies have found large variations in the content of Cry j 1, a major allergen of C. japonica pollinosis, suggesting that pollinosis could be reduced by replacing current C. japonica varieties with trees that produce less Cry j 1. In this study, Cry j I contents were compared in pollen produced with and without inducing male flowering by applying gibberellic acid (GA), which is a very useful technique for stimulating pollen production in targeted trees. No effect of GA application was detected, showing that pollen collected from GA-treated trees could be used in further investigations of the pollen's variability in Cry j 1 contents. GA application could also help in screening programs to identify trees that produce pollen with low allergen contents from candidates that generate sparse amounts of pollen. Furthermore, intraclonal variability of Cry j 1 content was found to be very low compared to interclonal variability. The stability of Cry j 1 content within clones suggests that selecting trees that produce less Cry j 1, followed by mass production via vegetative propagation, offers great potential for reducing the serious health problems caused by pollinosis in Japan.