| Abstract Detail
Water Relations Ryu, MoonYoung [1], Cho, Seok Keun [1], Son, ORa [1], Kim, Woo Taek [1]. Expression of AtPUB22 and AtPUB23, which encode a U-box E3 Ubiquitin Ligase, alter the plant’s response to abiotic stress in Arabidopsis. The U-box motif is a conserved domain found in the diverse isoforms of E3 Ub ligase in eukaryotes. From water-stressed Arabidopsis, we isolated AtPUB22 and AtPUB23 genes encoding proteins containing single U-box motif in their N-terminal region. In vitro ubiquitination and site-directed mutagenesis assays revealed that AtPUB22 and AtPUB23 possessed E3 Ub ligase activity, and the U-box motif was essential for its enzyme activity. RT-PCR and RNA gel blot analysis showed that AtPUB22 and AtPUB23 mRNAs were induced rapidly by a broad spectrum of abiotic stresses, including drought, high salinity, cold temperature, and mechanical wounding, suggesting their role in the early events in the abiotic-related defense response. Also, transgenic Arabidopsis plants that constitutively expressed the AtPUB22 and AtPUB23 genes under the control of the CaMV 35S promoter had markedly longer roots than the wild type in the normal conditions. In addition, AtPUB22 and AtPUB23 over-expressing plants displayed increased sensitivity to water stress and mild salinity. In contrast, the atpub22 and atpub23 knockout mutants as well as atpub22/atpub23 double mutants showed significantly increased tolerant to drought stress in comparison with the wild type plants. Although the physiological function of AtPUB22 and AtPUB23 are not yet clear, there are several possibilities for its involvement in a subset of physiological responses to counteract dehydration and high salinity stresses in transgenic Arabidopsis seedlings.
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1 - YONSEI UNIVERSITY, Department of BIOLOGY, Yonsei Science Research Center S134, 134, Sinchon-dong, Seodaemun-gu, Seoul, 120, South Korea
Keywords:
E3 ubiquitin ligase
abiotic stress
AtPUB22
AtPUB23.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P09017
Abstract ID:1183 |
