27 シロイヌナズナ(-)-ABA非感受性変異株の分離と解析

概要

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Abscisic acid (ABA) plays prominent roles on plant growth and development. To understand the mechanism how ABA is perceived and its signal is transduced, we screened Arabidopsis mutants, which were able to germinate in the presence of (-)-ABA, an unnatural stereoisomer of (+)-ABA. The concentration of (-)-ABA, which inhibits wild-type germination, was 3-fold higher than that of (+)-ABA. We screened 360,000 M2 seeds, isolated 40 mutants, and characterized 28 mutants. Twenty-two mutants were able to germinate on both 10 micro M (-)-ABA as well as 3 micro M (+)- ABA. These mutations fell into 3 complementation groups; abi3, abi4, and abi5. In contrast, other 6 mutants showed germinability on 10 micro M (-)-ABA, but they failed to germinate on 3 micro M (+)-ABA. These mutations fell into 3 complementation groups; abi3, chol, and cho2. The chol and cho2 loci were mapped onto bottom of chromosome 5 and chromosome 4, respectively. All mutants exhibits less sensitivity to both (+)-ABA and (-)-ABA, but the degree of reduced sensitivity to (+)-ABA or (-)-ABA were different among the mutants. The abi4, chol, and cho2 mutants showed more reduced sensitivity to (-)-ABA rather than (+)-ABA. In contrast, the abi5 mutants showed more reduced sensitivity to (+)-ABA compared to (-)-ABA. The overlapping ABA response pathways in seeds that are distinguished by the stereoisomers will be discussed.
植物化学調節学会の論文
2001-10-09