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. 2001 Oct;159(2):767–776. doi: 10.1093/genetics/159.2.767

Gibberellins are not required for normal stem growth in Arabidopsis thaliana in the absence of GAI and RGA.

K E King 1, T Moritz 1, N P Harberd 1
PMCID: PMC1461813  PMID: 11606551

Abstract

The growth of Arabidopsis thaliana is quantitatively regulated by the phytohormone gibberellin (GA) via two closely related nuclear GA-signaling components, GAI and RGA. Here we test the hypothesis that GAI and RGA function as "GA-derepressible repressors" of plant growth. One prediction of this hypothesis is that plants lacking GAI and RGA do not require GA for normal stem growth. Analysis of GA-deficient mutants lacking GAI and RGA confirms this prediction and suggests that in the absence of GAI and RGA, "growth" rather than "no growth" is the default state of plant stems. The function of the GA-signaling system is thus to act as a control system regulating the amount of this growth. We also demonstrate that the GA dose dependency of hypocotyl elongation is altered in mutants lacking GAI and RGA and propose that increments in GAI/RGA repressor function can explain the quantitative nature of GA responses.

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Selected References

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  1. Blazquez MA, Green R, Nilsson O, Sussman MR, Weigel D. Gibberellins promote flowering of arabidopsis by activating the LEAFY promoter . Plant Cell. 1998 May;10(5):791–800. doi: 10.1105/tpc.10.5.791. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bolle C., Koncz C., Chua N. H. PAT1, a new member of the GRAS family, is involved in phytochrome A signal transduction. Genes Dev. 2000 May 15;14(10):1269–1278. [PMC free article] [PubMed] [Google Scholar]
  3. Chandler PM, Robertson M. Gibberellin dose-response curves and the characterization of dwarf mutants of barley . Plant Physiol. 1999 Jun;120(2):623–632. doi: 10.1104/pp.120.2.623. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Cowling R. J., Kamiya Y., Seto H., Harberd N. P. Gibberellin dose-response regulation of GA4 gene transcript levels in Arabidopsis. Plant Physiol. 1998 Aug;117(4):1195–1203. doi: 10.1104/pp.117.4.1195. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Di Laurenzio L., Wysocka-Diller J., Malamy J. E., Pysh L., Helariutta Y., Freshour G., Hahn M. G., Feldmann K. A., Benfey P. N. The SCARECROW gene regulates an asymmetric cell division that is essential for generating the radial organization of the Arabidopsis root. Cell. 1996 Aug 9;86(3):423–433. doi: 10.1016/s0092-8674(00)80115-4. [DOI] [PubMed] [Google Scholar]
  6. Gendreau E., Traas J., Desnos T., Grandjean O., Caboche M., Höfte H. Cellular basis of hypocotyl growth in Arabidopsis thaliana. Plant Physiol. 1997 May;114(1):295–305. doi: 10.1104/pp.114.1.295. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Gilroy S., Jones R. L. Perception of Gibberellin and Abscisic Acid at the External Face of the Plasma Membrane of Barley (Hordeum vulgare L.) Aleurone Protoplasts. Plant Physiol. 1994 Apr;104(4):1185–1192. doi: 10.1104/pp.104.4.1185. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Harberd N. P., King K. E., Carol P., Cowling R. J., Peng J., Richards D. E. Gibberellin: inhibitor of an inhibitor of...? Bioessays. 1998 Dec;20(12):1001–1008. doi: 10.1002/(SICI)1521-1878(199812)20:12<1001::AID-BIES6>3.0.CO;2-O. [DOI] [PubMed] [Google Scholar]
  9. Hedden Peter, Kamiya Yuji. GIBBERELLIN BIOSYNTHESIS: Enzymes, Genes and Their Regulation. Annu Rev Plant Physiol Plant Mol Biol. 1997 Jun;48(NaN):431–460. doi: 10.1146/annurev.arplant.48.1.431. [DOI] [PubMed] [Google Scholar]
  10. Helariutta Y., Fukaki H., Wysocka-Diller J., Nakajima K., Jung J., Sena G., Hauser M. T., Benfey P. N. The SHORT-ROOT gene controls radial patterning of the Arabidopsis root through radial signaling. Cell. 2000 May 26;101(5):555–567. doi: 10.1016/s0092-8674(00)80865-x. [DOI] [PubMed] [Google Scholar]
  11. Ikeda A., Ueguchi-Tanaka M., Sonoda Y., Kitano H., Koshioka M., Futsuhara Y., Matsuoka M., Yamaguchi J. slender rice, a constitutive gibberellin response mutant, is caused by a null mutation of the SLR1 gene, an ortholog of the height-regulating gene GAI/RGA/RHT/D8. Plant Cell. 2001 May;13(5):999–1010. doi: 10.1105/tpc.13.5.999. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Peng J., Carol P., Richards D. E., King K. E., Cowling R. J., Murphy G. P., Harberd N. P. The Arabidopsis GAI gene defines a signaling pathway that negatively regulates gibberellin responses. Genes Dev. 1997 Dec 1;11(23):3194–3205. doi: 10.1101/gad.11.23.3194. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Peng J., Harberd N. P. Derivative Alleles of the Arabidopsis Gibberellin-Insensitive (gai) Mutation Confer a Wild-Type Phenotype. Plant Cell. 1993 Mar;5(3):351–360. doi: 10.1105/tpc.5.3.351. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Peng J., Richards D. E., Hartley N. M., Murphy G. P., Devos K. M., Flintham J. E., Beales J., Fish L. J., Worland A. J., Pelica F. 'Green revolution' genes encode mutant gibberellin response modulators. Nature. 1999 Jul 15;400(6741):256–261. doi: 10.1038/22307. [DOI] [PubMed] [Google Scholar]
  15. Peng J., Richards D. E., Moritz T., Caño-Delgado A., Harberd N. P. Extragenic suppressors of the Arabidopsis gai mutation alter the dose-response relationship of diverse gibberellin responses. Plant Physiol. 1999 Apr;119(4):1199–1208. doi: 10.1104/pp.119.4.1199. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Pysh L. D., Wysocka-Diller J. W., Camilleri C., Bouchez D., Benfey P. N. The GRAS gene family in Arabidopsis: sequence characterization and basic expression analysis of the SCARECROW-LIKE genes. Plant J. 1999 Apr;18(1):111–119. doi: 10.1046/j.1365-313x.1999.00431.x. [DOI] [PubMed] [Google Scholar]
  17. Richards D. E., Peng J., Harberd N. P. Plant GRAS and metazoan STATs: one family? Bioessays. 2000 Jun;22(6):573–577. doi: 10.1002/(SICI)1521-1878(200006)22:6<573::AID-BIES10>3.0.CO;2-H. [DOI] [PubMed] [Google Scholar]
  18. Richards Donald E., King Kathryn E., Ait-Ali Tahar, Harberd Nicholas P. HOW GIBBERELLIN REGULATES PLANT GROWTH AND DEVELOPMENT: A Molecular Genetic Analysis of Gibberellin Signaling. Annu Rev Plant Physiol Plant Mol Biol. 2001 Jun;52(NaN):67–88. doi: 10.1146/annurev.arplant.52.1.67. [DOI] [PubMed] [Google Scholar]
  19. Schumacher K., Schmitt T., Rossberg M., Schmitz G., Theres K. The Lateral suppressor (Ls) gene of tomato encodes a new member of the VHIID protein family. Proc Natl Acad Sci U S A. 1999 Jan 5;96(1):290–295. doi: 10.1073/pnas.96.1.290. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Silverstone A. L., Ciampaglio C. N., Sun T. The Arabidopsis RGA gene encodes a transcriptional regulator repressing the gibberellin signal transduction pathway. Plant Cell. 1998 Feb;10(2):155–169. doi: 10.1105/tpc.10.2.155. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Silverstone A. L., Mak P. Y., Martínez E. C., Sun T. P. The new RGA locus encodes a negative regulator of gibberellin response in Arabidopsis thaliana. Genetics. 1997 Jul;146(3):1087–1099. doi: 10.1093/genetics/146.3.1087. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Sun T. P., Kamiya Y. The Arabidopsis GA1 locus encodes the cyclase ent-kaurene synthetase A of gibberellin biosynthesis. Plant Cell. 1994 Oct;6(10):1509–1518. doi: 10.1105/tpc.6.10.1509. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Sun Tp., Goodman H. M., Ausubel F. M. Cloning the Arabidopsis GA1 Locus by Genomic Subtraction. Plant Cell. 1992 Feb;4(2):119–128. doi: 10.1105/tpc.4.2.119. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Wilson R. N., Heckman J. W., Somerville C. R. Gibberellin Is Required for Flowering in Arabidopsis thaliana under Short Days. Plant Physiol. 1992 Sep;100(1):403–408. doi: 10.1104/pp.100.1.403. [DOI] [PMC free article] [PubMed] [Google Scholar]

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