title: A WD40 protein, AtGHS40, negatively modulates abscisic acid degrading and signaling genes during seedling growth under high glucose conditions.
abstract: The Arabidopsis thaliana T-DNA insertion mutant glucose hypersensitive (ghs) 40-1 exhibited hypersensitivity to glucose (Glc) and abscisic acid (ABA). The ghs40-1 mutant displayed severely impaired cotyledon greening and expansion and showed enhanced reduction in hypocotyl elongation of dark-grown seedlings when grown in Glc concentrations higher than 3 %. The Glc-hypersensitivity of ghs40-1 was correlated with the hyposensitive phenotype of 35S::AtGHS40 seedlings. The phenotypes of ghs40-1 were recovered by complementation with 35S::AtGHS40. The AtGHS40 (At5g11240) gene encodes a WD40 protein localized primarily in the nucleus and nucleolus using transient expression of AtGHS40-mRFP in onion cells and of AtGHS40-EGFP and EGFP-AtGHS40 in Arabidopsis protoplasts. The ABA biosynthesis inhibitor fluridone extensively rescued Glc-mediated growth arrest. Quantitative real time-PCR analysis showed that AtGHS40 was involved in the control of Glc-responsive genes. AtGHS40 acts downstream of HXK1 and is activated by ABI4 while ABI4 expression is negatively modulated by AtGHS40 in the Glc signaling network. However, AtGHS40 may not affect ABI1 and SnRK2.6 gene expression. Given that AtGHS40 inhibited ABA degrading and signaling gene expression levels under high Glc conditions, a new circuit of fine-tuning modulation by which ABA and ABA signaling gene expression are modulated in balance, occurred in plants. Thus, AtGHS40 may play a role in ABA-mediated Glc signaling during early seedling development. The biochemical function of AtGHS40 is also discussed.
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan.|NCHU-UCD Plant and Food Biotechnology Center, NCHU, Taichung, 40227, Taiwan.|Agricultural Biotechnology Center, NCHU, Taichung, 40227, Taiwan.
authors.forename: Yu-Chun
authors.initials: YC
authors.lastname: Hsiao
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan.|NCHU-UCD Plant and Food Biotechnology Center, NCHU, Taichung, 40227, Taiwan.|Agricultural Biotechnology Center, NCHU, Taichung, 40227, Taiwan.|School of Life Sciences, Southwest University, Chongqing, China.
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Hsu
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan.|NCHU-UCD Plant and Food Biotechnology Center, NCHU, Taichung, 40227, Taiwan.|Agricultural Biotechnology Center, NCHU, Taichung, 40227, Taiwan.
authors.forename: Yun-Chu
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan.
authors.forename: Yi-Lin
authors.initials: YL
authors.lastname: Chang
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan. cswang2@nchu.edu.tw.|NCHU-UCD Plant and Food Biotechnology Center, NCHU, Taichung, 40227, Taiwan. cswang2@nchu.edu.tw.|Agricultural Biotechnology Center, NCHU, Taichung, 40227, Taiwan. cswang2@nchu.edu.tw.
authors.forename: Co-Shine
authors.initials: CS
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D036226:Seedlings / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D000040:Abscisic Acid; D005947:Glucose
keywords: ABA; Arabidopsis thaliana; Glc-hypersensitive; Seedling growth; WD40