A Stress-Responsive Caleosin-Like Protein, AtCLO4, Acts as a Negative Regulator of ABA Responses in Arabidopsis
- Authors
- Kim, Yun Young; Jung, Kwang Wook; Yoo, Kyoung Shin; Jeung, Ji Ung; Shin, Jeong Sheop
- Issue Date
- May-2011
- Publisher
- OXFORD UNIV PRESS
- Keywords
- ABA response; Arabidopsis thaliana; CaBP; Caleosin; Drought tolerance; Stomatal control
- Citation
- PLANT AND CELL PHYSIOLOGY, v.52, no.5, pp.874 - 884
- Indexed
- SCIE
SCOPUS
- Journal Title
- PLANT AND CELL PHYSIOLOGY
- Volume
- 52
- Number
- 5
- Start Page
- 874
- End Page
- 884
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/112584
- DOI
- 10.1093/pcp/pcr039
- ISSN
- 0032-0781
- Abstract
- Caleosins or related sequences have been found in a wide range of higher plants. In Arabidopsis, seed-specific caleosins are viewed as oil-body (OB)-associated proteins that possess Ca(2+)-dependent peroxygenase activity and are involved in processes of lipid degradation. Recent experimental evidence suggests that one of the Arabidopsis non-seed caleosins, AtCLO3, is involved in controlling stomatal aperture during the drought response; the roles of the other caleosin-like proteins in Arabidopsis remain largely uncharacterized. We have demonstrated that a novel stress-responsive and OB-associated Ca(2+)-binding caleosin-like protein, AtCLO4, is expressed in non-seed tissues of Arabidopsis, including guard cells, and down-regulated following exposure to exogenous ABA and salt stress. At the seed germination stage, a loss-of-function mutant (atclo4) was hypersensitive to ABA, salt and mannitol stresses, whereas AtCLO4-overexpressing (Ox) lines were more hyposensitive to those stresses than the wild type. In adult stage, atclo4 mutant and AtCLO4-Ox plants showed enhanced and decreased drought tolerance, respectively. Following exposure to exogenous ABA, the expression of key ABA-dependent regulatory genes, such as ABF3 and ABF4, was up-regulated in the atclo4 mutant, while it was down-regulated in AtCLO4-Ox lines. Based on these results, we propose that the OB-associated Ca(2+)-binding AtCLO4 protein acts as a negative regulator of ABA responses in Arabidopsis.
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Collections - College of Life Sciences and Biotechnology > Division of Life Sciences > 1. Journal Articles
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