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. 1997 Jan;9(1):37–47. doi: 10.1105/tpc.9.1.37

Photo and hormonal control of meristem identity in the Arabidopsis flower mutants apetala2 and apetala1.

J K Okamuro 1, W Szeto 1, C Lotys-Prass 1, K D Jofuku 1
PMCID: PMC156899  PMID: 9014363

Abstract

We have analyzed the contributions of phytochrome and gibberellin signal transduction to the control of flower meristem identity in the Arabidopsis mutants apetala1 (ap1) and apetala2 (ap2). ap1 flowers are partially defective for the establishment of flower meristem identity and are characterized by the production of ectopic secondary or axillary flowers and by branching. Axillary flower production is also induced in ap2-1 flowers by short-day photoperiod and is suppressed by hy1, a mutation blocking phytochrome activity. The production of axillary flower by ap2-1 is also suppressed by exogenous gibberellins and by spindly (spy), a mutation that activates basal gibberellin signal transduction in hormone-independent manner. Ectopic axillary flower production and floral branching by ap1 flowers are also suppressed by spy. We conclude that gibberellins promote flower meristem identity and that the inflorescence-like traits of ap2-1 and ap1-1 flowers are due in part to SPY gene activity.

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Selected References

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  1. Bowman J. L., Drews G. N., Meyerowitz E. M. Expression of the Arabidopsis floral homeotic gene AGAMOUS is restricted to specific cell types late in flower development. Plant Cell. 1991 Aug;3(8):749–758. doi: 10.1105/tpc.3.8.749. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bowman J. L., Smyth D. R., Meyerowitz E. M. Genes directing flower development in Arabidopsis. Plant Cell. 1989 Jan;1(1):37–52. doi: 10.1105/tpc.1.1.37. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Clack T., Mathews S., Sharrock R. A. The phytochrome apoprotein family in Arabidopsis is encoded by five genes: the sequences and expression of PHYD and PHYE. Plant Mol Biol. 1994 Jun;25(3):413–427. doi: 10.1007/BF00043870. [DOI] [PubMed] [Google Scholar]
  4. Drews G. N., Bowman J. L., Meyerowitz E. M. Negative regulation of the Arabidopsis homeotic gene AGAMOUS by the APETALA2 product. Cell. 1991 Jun 14;65(6):991–1002. doi: 10.1016/0092-8674(91)90551-9. [DOI] [PubMed] [Google Scholar]
  5. Gianfagna T., Zeevaart J. A., Lusk W. J. Effect of photoperiod on the metabolism of deuterium-labeled gibberellin a(53) in spinach. Plant Physiol. 1983 May;72(1):86–89. doi: 10.1104/pp.72.1.86. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Irish V. F., Sussex I. M. Function of the apetala-1 gene during Arabidopsis floral development. Plant Cell. 1990 Aug;2(8):741–753. doi: 10.1105/tpc.2.8.741. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Jacobsen S. E., Olszewski N. E. Mutations at the SPINDLY locus of Arabidopsis alter gibberellin signal transduction. Plant Cell. 1993 Aug;5(8):887–896. doi: 10.1105/tpc.5.8.887. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Jofuku K. D., den Boer B. G., Van Montagu M., Okamuro J. K. Control of Arabidopsis flower and seed development by the homeotic gene APETALA2. Plant Cell. 1994 Sep;6(9):1211–1225. doi: 10.1105/tpc.6.9.1211. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Jordan E. T., Hatfield P. M., Hondred D., Talon M., Zeevaart J. A., Vierstra R. D. Phytochrome A overexpression in transgenic tobacco. Correlation of dwarf phenotype with high concentrations of phytochrome in vascular tissue and attenuated gibberellin levels. Plant Physiol. 1995 Mar;107(3):797–805. doi: 10.1104/pp.107.3.797. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Kobayashi M., Gaskin P., Spray C. R., Suzuki Y., Phinney B. O., MacMillan J. Metabolism and Biological Activity of Gibberellin A4 in Vegetative Shoots of Zea mays, Oryza sativa, and Arabidopsis thaliana. Plant Physiol. 1993 Jun;102(2):379–386. doi: 10.1104/pp.102.2.379. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kunst L., Klenz J. E., Martinez-Zapater J., Haughn G. W. AP2 Gene Determines the Identity of Perianth Organs in Flowers of Arabidopsis thaliana. Plant Cell. 1989 Dec;1(12):1195–1208. doi: 10.1105/tpc.1.12.1195. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Mandel M. A., Gustafson-Brown C., Savidge B., Yanofsky M. F. Molecular characterization of the Arabidopsis floral homeotic gene APETALA1. Nature. 1992 Nov 19;360(6401):273–277. doi: 10.1038/360273a0. [DOI] [PubMed] [Google Scholar]
  13. Meyerowitz E. M., Bowman J. L., Brockman L. L., Drews G. N., Jack T., Sieburth L. E., Weigel D. A genetic and molecular model for flower development in Arabidopsis thaliana. Dev Suppl. 1991;1:157–167. [PubMed] [Google Scholar]
  14. Okamuro J. K., den Boer B. G., Jofuku K. D. Regulation of Arabidopsis flower development. Plant Cell. 1993 Oct;5(10):1183–1193. doi: 10.1105/tpc.5.10.1183. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Okamuro J. K., den Boer B. G., Lotys-Prass C., Szeto W., Jofuku K. D. Flowers into shoots: photo and hormonal control of a meristem identity switch in Arabidopsis. Proc Natl Acad Sci U S A. 1996 Nov 26;93(24):13831–13836. doi: 10.1073/pnas.93.24.13831. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Parks B. M., Quail P. H. Phytochrome-Deficient hy1 and hy2 Long Hypocotyl Mutants of Arabidopsis Are Defective in Phytochrome Chromophore Biosynthesis. Plant Cell. 1991 Nov;3(11):1177–1186. doi: 10.1105/tpc.3.11.1177. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Shannon S., Meeks-Wagner D. R. A Mutation in the Arabidopsis TFL1 Gene Affects Inflorescence Meristem Development. Plant Cell. 1991 Sep;3(9):877–892. doi: 10.1105/tpc.3.9.877. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Shannon S., Meeks-Wagner D. R. Genetic Interactions That Regulate Inflorescence Development in Arabidopsis. Plant Cell. 1993 Jun;5(6):639–655. doi: 10.1105/tpc.5.6.639. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Sharrock R. A., Quail P. H. Novel phytochrome sequences in Arabidopsis thaliana: structure, evolution, and differential expression of a plant regulatory photoreceptor family. Genes Dev. 1989 Nov;3(11):1745–1757. doi: 10.1101/gad.3.11.1745. [DOI] [PubMed] [Google Scholar]
  20. Smyth D. R., Bowman J. L., Meyerowitz E. M. Early flower development in Arabidopsis. Plant Cell. 1990 Aug;2(8):755–767. doi: 10.1105/tpc.2.8.755. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Weigel D. The genetics of flower development: from floral induction to ovule morphogenesis. Annu Rev Genet. 1995;29:19–39. doi: 10.1146/annurev.ge.29.120195.000315. [DOI] [PubMed] [Google Scholar]
  22. 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]
  23. Xu Y. L., Li L., Wu K., Peeters A. J., Gage D. A., Zeevaart J. A. The GA5 locus of Arabidopsis thaliana encodes a multifunctional gibberellin 20-oxidase: molecular cloning and functional expression. Proc Natl Acad Sci U S A. 1995 Jul 3;92(14):6640–6644. doi: 10.1073/pnas.92.14.6640. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Zeevaart J. A., Gage D. A. ent-kaurene biosynthesis is enhanced by long photoperiods in the long-day plants Spinacia oleracea L. and Agrostemma githago L. Plant Physiol. 1993 Jan;101(1):25–29. doi: 10.1104/pp.101.1.25. [DOI] [PMC free article] [PubMed] [Google Scholar]

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