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Characterization of ABA binding in ABA-insensitive mutant abi2 of Arabidopsis thaliana

Zhena Huiqiong, Chen Jichu, Zhao Yuju, Xu Zhihong

Shanghai Institute of Plant Physiology, The Chinese Academy of Sciences. Shanghai 200032

Abstract

There are distinct differences in physiological characteristics,such as seed domancy, sensitivity to ABA and aperture of the stomata between wild-type and the ABA-insensitive mutant abi2 from Arabidopsis thaliana (Landsberg) ~(3)H-ABA binding in subcellular fractions(4 000-100 000×g) of wild-type and abi2 showed that the strongest specifically-bound activity was in the 38 000×g pellet fraction, the optimum temperature of ABA binding was 20℃. Scatchard plot ofsaturation kinetics showed that there was one kind of binding site in abi2, but two in wild-type. By analysis of electropherogram on SDS-PAGE of~(3)H-ABA-labelled 38 000×g fractions from leaves of abi2 and wild-type,three peaks of ~(3)H-ABA-binding activity were found in wild-type, but only one in abi2.These results suggest that the insensitivity to ABA of abi2 might be caused by mutation of ABA-binding sites.

Key words: Abscisic acid;Arabidopsis thaliana;Insensitive mutunt;Binding site

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Citing This Article：

Zhena Huiqiong, Chen Jichu, Zhao Yuju, Xu Zhihong. Characterization of ABA binding in ABA-insensitive mutant abi2 of Arabidopsis thaliana. Acta Physiol Sin 1997; 49 (2): (in Chinese with English abstract).