title: Arabidopsis DREB2C modulates ABA biosynthesis during germination.
abstract: Plant dehydration-responsive element binding factors (DREBs) are transcriptional regulators of the APETELA2/Ethylene Responsive element-binding Factor (AP2/ERF) family that control expression of abiotic stress-related genes. We show here that under conditions of mild heat stress, constitutive overexpression seeds of transgenic DREB2C overexpression Arabidopsis exhibit delayed germination and increased abscisic acid (ABA) content compared to untransformed wild-type (WT). Treatment with fluridone, an inhibitor of the ABA biosynthesis abrogated these effects. Expression of an ABA biosynthesis-related gene, 9-cis-epoxycarotenoid dioxygenase 9 (NCED9) was up-regulated in the DREB2C overexpression lines compared to WT. DREB2C was able to trans-activate expression of NCED9 in Arabidopsis leaf protoplasts in vitro. Direct and specific binding of DREB2C to a complete DRE on the NCED9 promoter was observed in electrophoretic mobility shift assays. Exogenous ABA treatment induced DREB2C expression in germinating seeds of WT. Vegetative growth of transgenic DREB2C overexpression lines was more strongly inhibited by exogenous ABA compared to WT. These results suggest that DREB2C is a stress- and ABA-inducible gene that acts as a positive regulator of ABA biosynthesis in germinating seeds through activating NCED9 expression.
authors.affiliation: Systems and Synthetic Agrobiotech Center and PMBBRC, Division of Applied Life Science, Graduate School of Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Jihyun
authors.initials: J
authors.lastname: Je
authors.affiliation: Systems and Synthetic Agrobiotech Center and PMBBRC, Division of Applied Life Science, Graduate School of Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Huan
authors.initials: H
authors.lastname: Chen
authors.affiliation: Systems and Synthetic Agrobiotech Center and PMBBRC, Division of Applied Life Science, Graduate School of Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Chieun
authors.initials: C
authors.lastname: Song
authors.affiliation: Systems and Synthetic Agrobiotech Center and PMBBRC, Division of Applied Life Science, Graduate School of Gyeongsang National University, Jinju 660-701, Republic of Korea; Research Institute of Natural Science, Department of Biochemistry, Gyeongsang National University, Jinju 660-701, Republic of Korea. Electronic address: colim@gnu.ac.kr.
authors.forename: Chae Oh
authors.initials: CO
authors.lastname: Lim
mesh_terms: D000040:Abscisic Acid / Q000096:biosynthesis*; D017360:Arabidopsis / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D024202:Electrophoretic Mobility Shift Assay; D018525:Germination; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C573537:DREB2C protein, Arabidopsis; D000040:Abscisic Acid
keywords: Gene expression; Heat stress; Transcription factor; Transgenic plant