Abstract
The induction of α-amylase triggered by gibberellic acid in barley embryos is repressed by sugars. We investigated the effects of glucose on the gibberellin signal transduction pathway to localize the site of interaction of the sugar/hormone signalling pathways. Our results indicate that glucose represses gibberellin signalling late along this hormone transduction pathway, downstream of transcription of the gibberellin-modulated transcriptional activator (GAMYB) needed for α-amylase induction. This result suggests either that glucose repression is transduced by a pathway independent of gibberellin signalling or that repression occurs at the level of GAMYB translation.
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Bethke, P.C., Schuurink, R. and Jones, R.L. 1997. Hormonal signaling in cereal aleurone. J. Exp. Bot. 48: 1337–1356.
Bethke, P.C. and Jones, R.L. 1999. Gibberellin signaling. Curr. Opin. Plant Biol. 1: 440–446.
Gausing, K. and Barkardottir, R. 1986. Structure and expression of ubiquitin genes in higher plants. Eur. J. Biochem. 158: 57–62.
Gubler, F., Kalla, R., Roberts, J.K. and Jacobsen, J.V. 1995. Gibberellin-regulated expression of a myb gene in barley aleurone cells: evidence for a myb transactivation of a high-pI α-amylase gene promoter. Plant Cell 7: 1879–1891.
Gubler, F., Raventos, D., Keys, M., Watts, R., Mundy, J. and Jacobsen, J.V. 1999. Target genes and regulatory domains of the GAMYB transcriptional activator in cereal aleurone. Plant J. 17: 1–9.
Jones, R.L. and Varner, J.E. 1967. The bioassay of gibberellins. Planta 72: 53–59.
Kouchi, H. and Hata, S. 1993. Isolation and characterization of a novel nodulin cDNA representing genes expressed at early stages of soybean nodule development. Mol. Gen. Genet. 238: 106–119.
Morita, A., Umemura, T., Kuroyanagi, M., Futsuhara, Y., Perata, P. and Yamaguchi, J. 1998. Functional dissection of a sugarrepressed α-amylase gene (Ramy1A) promoter in rice embryos. FEBS Lett. 423: 81–85.
Mitsui, T. and Itoh, K. 1997. The α-amylase multigene family. Trends Plant Sci. ;2: 255–261.
Ohto, M. Hayashi, K., Isobe, M. and Nakamura, K. 1995. Involvement of Ca2+ signalling in the sugar-inducible expression of genes coding for sporamin and α-amylase of sweet potato. Plant J. 7: 297–307.
Penson, S.P., Schuurink, R.C., Fath, A., Gubler, F., Jacobsen, J.V. and Jones R.L. 1996. cGMP is required for gibberellic acid-induced gene expression in barley aleurone. Plant Cell 8: 2325–2333
Perata, P., Matsukura, C., Vernieri, P. and Yamaguchi, J. 1997. Sugar repression of a gibberellin-dependent signaling pathway in barley embryos. Plant Cell 9: 2197–2208.
Rogers, J.C. 1985. Two barley α-amylase gene families are regulated differently in aleurone cells. J. Biol. Chem. 260: 3731–3738.
Rook, F., Gerrits, N., Kortstee, A., van Kampen, M., Borrias, M., Weisbeek, P. and Smeekens, S. 1998. Sucrose-specific signalling represses translation of the Arabidopsis ATB2 bZIP transcription factor gene. Plant J. 15: 253–263.
Sheen, J., Zhou Li, H.-T. and Jang, J.-C. 1999. Sugar as signalling molecules. Curr. Opin. Plant Biol. 2: 410–418.
Takeda, S., Mano, S., Ohto, M. and Nakamura, K 1994. Inhibitors of protein phosphatases 1 and 2A block sugar-inducible gene expression in plants. Plant Physiol. 106: 567–574.
Toyofuku, K., Umemura, T. and Yamaguchi, J. 1998. Promoter elements required for sugar-repression of the Ramy3D gene for α-amylase in rice. FEBS Lett. 428: 275–280.
Toyofuku, K., Loreti, E., Vernieri, P., Alpi, A., Perata, P. and Yamaguchi, J. 2000. Glucose modulates the abscisic acid-inducible Rab 16A gene in cereal embryos. Plant Mol. Biol. 42: 451–460.
Yu, S.-M., Lee, Y.-C., Fang, S.-C., Hwa, S.-F. and Liu L.-F. 1996. Sugars act as signal molecules and osmotica to regulate the expression of α-amylase genes and metabolic activities in germinating cereal grains. Plant Mol. Biol. 30: 1277–1289.
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Loreti, E., Matsukura, Ca., Gubler, F. et al. Glucose repression of α-amylase in barley embryos is independent of GAMYB transcription. Plant Mol Biol 44, 85–90 (2000). https://doi.org/10.1023/A:1006496520809
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DOI: https://doi.org/10.1023/A:1006496520809