蘚類ヒメツリガネゴケのABA非感受性株および形質転換体におけるストレス耐性

抄録

Exogenous application of a phytohormone abscisic acid (ABA) has been shown to induce both morphological changes leading to brood cell formation and stress tolerance in Physcomitrella patens protonema cells accompanied by the accumulation of low-molecular-weight soluble sugars and LEA-like boiling-soluble proteins. We used the transgenic D2-1 line expressing the catalytic domain of protein phosphatase 2C negatively regulating ABA signaling, and the ABA-less-sensitive AR7 mutant which has been isolated by ultraviolet mutagenesis, to compare their stress tolerance with that of wild type. Without ABA treatment, D2-1 and AR7 showed similar growth to that of wild type. However, the both lines were sensitive to freezing, desiccation and osmotic stresses with or without ABA treatment, whereas the ABA treatment enhanced tolerance in wild type to these abiotic stresses. These results indicate that ABA plays a major role in stress tolerance in P. patens.