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Eukaryotic release factor 1-2 affects Arabidopsis responses to glucose and phytohormones during germination and early seedling development.

Zhou X, Cooke P, Li L - J. Exp. Bot. (2009)

Bottom Line: The eRF1-2 gene was found to be specifically induced by glucose.By contrast, the loss-of-function erf1-2 mutant exhibited resistance to paclobutrazol, suggesting that eRF1-2 may exert a negative effect on the GA signalling pathway.Collectively, these data provide evidence in support of a novel role of eRF1-2 in affecting glucose and phytohormone responses in modulating plant growth and development.

View Article: PubMed Central - PubMed

Affiliation: Robert W Holley Center for Agriculture and Health, U.S. Department of Agriculture-Agricultural Research Service, Cornell University, Ithaca, NY 14853, USA.

ABSTRACT
Germination and early seedling development are coordinately regulated by glucose and phytohormones such as ABA, GA, and ethylene. However, the molecules that affect plant responses to glucose and phytohormones remain to be fully elucidated. Eukaryotic release factor 1 (eRF1) is responsible for the recognition of the stop codons in mRNAs during protein synthesis. Accumulating evidence indicates that eRF1 functions in other processes in addition to translation termination. The physiological role of eRF1-2, a member of the eRF1 family, in Arabidopsis was examined here. The eRF1-2 gene was found to be specifically induced by glucose. Arabidopsis plants overexpressing eRF1-2 were hypersensitive to glucose during germination and early seedling development. Such hypersensitivity to glucose was accompanied by a dramatic reduction of the expression of glucose-regulated genes, chlorophyll a/b binding protein and plastocyanin. The hypersensitive response was not due to the enhanced accumulation of ABA. In addition, the eRF1-2 overexpressing plants showed increased sensitivity to paclobutrazol, an inhibitor of GA biosynthesis, and exogenous GA restored their normal growth. By contrast, the loss-of-function erf1-2 mutant exhibited resistance to paclobutrazol, suggesting that eRF1-2 may exert a negative effect on the GA signalling pathway. Collectively, these data provide evidence in support of a novel role of eRF1-2 in affecting glucose and phytohormone responses in modulating plant growth and development.

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Structure and expression patterns of Arabidopsis eRF1-2. (A) Structure analysis of the eRF1-2 protein. The essential NIKS and GGQ motifs in the anticodon loop and the aminoacyl acceptor stem of eRF1-2 are indicated. (B) qRT-PCR analysis of the expression pattern of eRF1-2. R, roots; S, stems; YL, 28-d-old rosette leaves; ML, 40-d-old rosette leaves; CL, cauline leaves; FB, flower buds; F, open flowers. (C) Localization of GUS activity in 3-d-old transgenic Arabidopsis seedlings expressing ProeRF1-2:GUS. GUS staining of 3-d-old seedling (1), hypocotyl (2), root elongation zone (3), root tip (4), shoot meristem tissue (5), cotyledon (6), and guard cell (7). Bar=1 mm. (This figure is available in colour at JXB online.)
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fig1: Structure and expression patterns of Arabidopsis eRF1-2. (A) Structure analysis of the eRF1-2 protein. The essential NIKS and GGQ motifs in the anticodon loop and the aminoacyl acceptor stem of eRF1-2 are indicated. (B) qRT-PCR analysis of the expression pattern of eRF1-2. R, roots; S, stems; YL, 28-d-old rosette leaves; ML, 40-d-old rosette leaves; CL, cauline leaves; FB, flower buds; F, open flowers. (C) Localization of GUS activity in 3-d-old transgenic Arabidopsis seedlings expressing ProeRF1-2:GUS. GUS staining of 3-d-old seedling (1), hypocotyl (2), root elongation zone (3), root tip (4), shoot meristem tissue (5), cotyledon (6), and guard cell (7). Bar=1 mm. (This figure is available in colour at JXB online.)

Mentions: The predicted eRF1-2 protein of Arabidopsis contains 434 amino acid residues with a deduced molecular mass of 48.9 kDa. Arabidopsis eRF1-2 shares 73% amino acid sequence identity with human eRF1 and carries three conserved domains, which correspond to the anticodon loop, the aminoacyl acceptor stem, and the T stem of tRNA, respectively (Fig. 1A). The NIKS and GGQ motifs, which are shown to be responsible for interaction with the ribosome and hydrolysis of peptidyl-tRNA (Frolova et al., 1999, 2002), are located between amino acids 58 and 61, and amino acids 180 and 182, respectively (Fig. 1A).


Eukaryotic release factor 1-2 affects Arabidopsis responses to glucose and phytohormones during germination and early seedling development.

Zhou X, Cooke P, Li L - J. Exp. Bot. (2009)

Structure and expression patterns of Arabidopsis eRF1-2. (A) Structure analysis of the eRF1-2 protein. The essential NIKS and GGQ motifs in the anticodon loop and the aminoacyl acceptor stem of eRF1-2 are indicated. (B) qRT-PCR analysis of the expression pattern of eRF1-2. R, roots; S, stems; YL, 28-d-old rosette leaves; ML, 40-d-old rosette leaves; CL, cauline leaves; FB, flower buds; F, open flowers. (C) Localization of GUS activity in 3-d-old transgenic Arabidopsis seedlings expressing ProeRF1-2:GUS. GUS staining of 3-d-old seedling (1), hypocotyl (2), root elongation zone (3), root tip (4), shoot meristem tissue (5), cotyledon (6), and guard cell (7). Bar=1 mm. (This figure is available in colour at JXB online.)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2803205&req=5

fig1: Structure and expression patterns of Arabidopsis eRF1-2. (A) Structure analysis of the eRF1-2 protein. The essential NIKS and GGQ motifs in the anticodon loop and the aminoacyl acceptor stem of eRF1-2 are indicated. (B) qRT-PCR analysis of the expression pattern of eRF1-2. R, roots; S, stems; YL, 28-d-old rosette leaves; ML, 40-d-old rosette leaves; CL, cauline leaves; FB, flower buds; F, open flowers. (C) Localization of GUS activity in 3-d-old transgenic Arabidopsis seedlings expressing ProeRF1-2:GUS. GUS staining of 3-d-old seedling (1), hypocotyl (2), root elongation zone (3), root tip (4), shoot meristem tissue (5), cotyledon (6), and guard cell (7). Bar=1 mm. (This figure is available in colour at JXB online.)
Mentions: The predicted eRF1-2 protein of Arabidopsis contains 434 amino acid residues with a deduced molecular mass of 48.9 kDa. Arabidopsis eRF1-2 shares 73% amino acid sequence identity with human eRF1 and carries three conserved domains, which correspond to the anticodon loop, the aminoacyl acceptor stem, and the T stem of tRNA, respectively (Fig. 1A). The NIKS and GGQ motifs, which are shown to be responsible for interaction with the ribosome and hydrolysis of peptidyl-tRNA (Frolova et al., 1999, 2002), are located between amino acids 58 and 61, and amino acids 180 and 182, respectively (Fig. 1A).

Bottom Line: The eRF1-2 gene was found to be specifically induced by glucose.By contrast, the loss-of-function erf1-2 mutant exhibited resistance to paclobutrazol, suggesting that eRF1-2 may exert a negative effect on the GA signalling pathway.Collectively, these data provide evidence in support of a novel role of eRF1-2 in affecting glucose and phytohormone responses in modulating plant growth and development.

View Article: PubMed Central - PubMed

Affiliation: Robert W Holley Center for Agriculture and Health, U.S. Department of Agriculture-Agricultural Research Service, Cornell University, Ithaca, NY 14853, USA.

ABSTRACT
Germination and early seedling development are coordinately regulated by glucose and phytohormones such as ABA, GA, and ethylene. However, the molecules that affect plant responses to glucose and phytohormones remain to be fully elucidated. Eukaryotic release factor 1 (eRF1) is responsible for the recognition of the stop codons in mRNAs during protein synthesis. Accumulating evidence indicates that eRF1 functions in other processes in addition to translation termination. The physiological role of eRF1-2, a member of the eRF1 family, in Arabidopsis was examined here. The eRF1-2 gene was found to be specifically induced by glucose. Arabidopsis plants overexpressing eRF1-2 were hypersensitive to glucose during germination and early seedling development. Such hypersensitivity to glucose was accompanied by a dramatic reduction of the expression of glucose-regulated genes, chlorophyll a/b binding protein and plastocyanin. The hypersensitive response was not due to the enhanced accumulation of ABA. In addition, the eRF1-2 overexpressing plants showed increased sensitivity to paclobutrazol, an inhibitor of GA biosynthesis, and exogenous GA restored their normal growth. By contrast, the loss-of-function erf1-2 mutant exhibited resistance to paclobutrazol, suggesting that eRF1-2 may exert a negative effect on the GA signalling pathway. Collectively, these data provide evidence in support of a novel role of eRF1-2 in affecting glucose and phytohormone responses in modulating plant growth and development.

Show MeSH
Related in: MedlinePlus