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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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Related in: MedlinePlus

ABA responses of Arabidopsis plants with altered expression of eRF1-2. (A) ABA levels in 10-d-old Arabidopsis seedlings grown on MS and MS with 6% glucose. Fifty milligrams of seedlings were used in ABA extraction. (B) Germination rate of a 6-d-old seedling grown on MS media containing 0, 0.3, 0.6, and 1 μM ABA. Emergence of the radicle is ascribed to germination. The data represent the average of two independent experiments. Bars indicate standard deviation.
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fig4: ABA responses of Arabidopsis plants with altered expression of eRF1-2. (A) ABA levels in 10-d-old Arabidopsis seedlings grown on MS and MS with 6% glucose. Fifty milligrams of seedlings were used in ABA extraction. (B) Germination rate of a 6-d-old seedling grown on MS media containing 0, 0.3, 0.6, and 1 μM ABA. Emergence of the radicle is ascribed to germination. The data represent the average of two independent experiments. Bars indicate standard deviation.

Mentions: Glucose can increase cellular ABA concentration by either increasing ABA synthesis or inhibiting degradation during germination (Arenas-Huertero et al., 2000; Cheng et al., 2002; Price et al., 2003). To test whether the hypersensitivity of the eRF1-2 overexpressing plants to glucose was attributable to the excessive accumulation of ABA in the cells, the ABA levels were examined in the 6-d-old transgenic seedlings grown on MS plates containing no glucose and 6% glucose, respectively. No significant difference in the ABA levels could be seen among WT, the two overexpressing lines, and the erf1-2 mutant in the absence of glucose (Fig. 4A). In the presence of 6% glucose, the ABA levels in the WT plants were increased as reported previously (Cheng et al., 2002). Interestingly, while the erf1-2 mutant showed a slightly enhanced level of ABA accumulation following glucose treatment, the eRF1-2 overexpressing lines contained less ABA than the WT (Fig. 4A), indicating that the hypersensitivity of the eRF1-2 overexpressing lines to glucose was not caused by excessive accumulation of cellular ABA in these plants.


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)

ABA responses of Arabidopsis plants with altered expression of eRF1-2. (A) ABA levels in 10-d-old Arabidopsis seedlings grown on MS and MS with 6% glucose. Fifty milligrams of seedlings were used in ABA extraction. (B) Germination rate of a 6-d-old seedling grown on MS media containing 0, 0.3, 0.6, and 1 μM ABA. Emergence of the radicle is ascribed to germination. The data represent the average of two independent experiments. Bars indicate standard deviation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: ABA responses of Arabidopsis plants with altered expression of eRF1-2. (A) ABA levels in 10-d-old Arabidopsis seedlings grown on MS and MS with 6% glucose. Fifty milligrams of seedlings were used in ABA extraction. (B) Germination rate of a 6-d-old seedling grown on MS media containing 0, 0.3, 0.6, and 1 μM ABA. Emergence of the radicle is ascribed to germination. The data represent the average of two independent experiments. Bars indicate standard deviation.
Mentions: Glucose can increase cellular ABA concentration by either increasing ABA synthesis or inhibiting degradation during germination (Arenas-Huertero et al., 2000; Cheng et al., 2002; Price et al., 2003). To test whether the hypersensitivity of the eRF1-2 overexpressing plants to glucose was attributable to the excessive accumulation of ABA in the cells, the ABA levels were examined in the 6-d-old transgenic seedlings grown on MS plates containing no glucose and 6% glucose, respectively. No significant difference in the ABA levels could be seen among WT, the two overexpressing lines, and the erf1-2 mutant in the absence of glucose (Fig. 4A). In the presence of 6% glucose, the ABA levels in the WT plants were increased as reported previously (Cheng et al., 2002). Interestingly, while the erf1-2 mutant showed a slightly enhanced level of ABA accumulation following glucose treatment, the eRF1-2 overexpressing lines contained less ABA than the WT (Fig. 4A), indicating that the hypersensitivity of the eRF1-2 overexpressing lines to glucose was not caused by excessive accumulation of cellular ABA in these plants.

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