Skip to main content
PMC home page
The Plant Cell logoLink to The Plant Cell
. 1999 Jun;11(6):1007–1018. doi: 10.1105/tpc.11.6.1007

Interactions among APETALA1, LEAFY, and TERMINAL FLOWER1 specify meristem fate.

S J Liljegren 1, C Gustafson-Brown 1, A Pinyopich 1, G S Ditta 1, M F Yanofsky 1
PMCID: PMC144247  PMID: 10368173

Abstract

Upon floral induction, the primary shoot meristem of an Arabidopsis plant begins to produce flower meristems rather than leaf primordia on its flanks. Assignment of floral fate to lateral meristems is primarily due to the cooperative activity of the flower meristem identity genes LEAFY (LFY), APETALA1 (AP1), and CAULIFLOWER. We present evidence here that AP1 expression in lateral meristems is activated by at least two independent pathways, one of which is regulated by LFY. In lfy mutants, the onset of AP1 expression is delayed, indicating that LFY is formally a positive regulator of AP1. We have found that AP1, in turn, can positively regulate LFY, because LFY is expressed prematurely in the converted floral meristems of plants constitutively expressing AP1. Shoot meristems maintain an identity distinct from that of flower meristems, in part through the action of genes such as TERMINAL FLOWER1 (TFL1), which bars AP1 and LFY expression from the influorescence shoot meristem. We show here that this negative regulation can be mutual because TFL1 expression is downregulated in plants constitutively expressing AP1. Therefore, the normally sharp phase transition between the production of leaves with associated shoots and formation of the flowers, which occurs upon floral induction, is promoted by positive feedback interactions between LFY and AP1, together with negative interactions of these two genes with TFL1.

Full Text

The Full Text of this article is available as a PDF (452.5 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Blázquez M. A., Soowal L. N., Lee I., Weigel D. LEAFY expression and flower initiation in Arabidopsis. Development. 1997 Oct;124(19):3835–3844. doi: 10.1242/dev.124.19.3835. [DOI] [PubMed] [Google Scholar]
  2. Bradley D., Ratcliffe O., Vincent C., Carpenter R., Coen E. Inflorescence commitment and architecture in Arabidopsis. Science. 1997 Jan 3;275(5296):80–83. doi: 10.1126/science.275.5296.80. [DOI] [PubMed] [Google Scholar]
  3. 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]
  4. Grbić B., Bleecker A. B. An altered body plan is conferred on Arabidopsis plants carrying dominant alleles of two genes. Development. 1996 Aug;122(8):2395–2403. doi: 10.1242/dev.122.8.2395. [DOI] [PubMed] [Google Scholar]
  5. Gustafson-Brown C., Savidge B., Yanofsky M. F. Regulation of the arabidopsis floral homeotic gene APETALA1. Cell. 1994 Jan 14;76(1):131–143. doi: 10.1016/0092-8674(94)90178-3. [DOI] [PubMed] [Google Scholar]
  6. Hempel F. D., Weigel D., Mandel M. A., Ditta G., Zambryski P. C., Feldman L. J., Yanofsky M. F. Floral determination and expression of floral regulatory genes in Arabidopsis. Development. 1997 Oct;124(19):3845–3853. doi: 10.1242/dev.124.19.3845. [DOI] [PubMed] [Google Scholar]
  7. Huala E., Sussex I. M. LEAFY Interacts with Floral Homeotic Genes to Regulate Arabidopsis Floral Development. Plant Cell. 1992 Aug;4(8):901–913. doi: 10.1105/tpc.4.8.901. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. 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]
  9. Kempin S. A., Savidge B., Yanofsky M. F. Molecular basis of the cauliflower phenotype in Arabidopsis. Science. 1995 Jan 27;267(5197):522–525. doi: 10.1126/science.7824951. [DOI] [PubMed] [Google Scholar]
  10. Konieczny A., Ausubel F. M. A procedure for mapping Arabidopsis mutations using co-dominant ecotype-specific PCR-based markers. Plant J. 1993 Aug;4(2):403–410. doi: 10.1046/j.1365-313x.1993.04020403.x. [DOI] [PubMed] [Google Scholar]
  11. Koornneef Maarten, Alonso-Blanco Carlos, Peeters Anton J. M., Soppe Wim. GENETIC CONTROL OF FLOWERING TIME IN ARABIDOPSIS. Annu Rev Plant Physiol Plant Mol Biol. 1998 Jun;49(NaN):345–370. doi: 10.1146/annurev.arplant.49.1.345. [DOI] [PubMed] [Google Scholar]
  12. Lee I., Wolfe D. S., Nilsson O., Weigel D. A LEAFY co-regulator encoded by UNUSUAL FLORAL ORGANS. Curr Biol. 1997 Feb 1;7(2):95–104. doi: 10.1016/s0960-9822(06)00053-4. [DOI] [PubMed] [Google Scholar]
  13. Levy YY, Dean C. The transition to flowering . Plant Cell. 1998 Dec;10(12):1973–1990. doi: 10.1105/tpc.10.12.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. 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]
  15. Mandel M. A., Yanofsky M. F. A gene triggering flower formation in Arabidopsis. Nature. 1995 Oct 12;377(6549):522–524. doi: 10.1038/377522a0. [DOI] [PubMed] [Google Scholar]
  16. Neff M. M., Neff J. D., Chory J., Pepper A. E. dCAPS, a simple technique for the genetic analysis of single nucleotide polymorphisms: experimental applications in Arabidopsis thaliana genetics. Plant J. 1998 May;14(3):387–392. doi: 10.1046/j.1365-313x.1998.00124.x. [DOI] [PubMed] [Google Scholar]
  17. Ohshima S., Murata M., Sakamoto W., Ogura Y., Motoyoshi F. Cloning and molecular analysis of the Arabidopsis gene Terminal Flower 1. Mol Gen Genet. 1997 Mar 26;254(2):186–194. doi: 10.1007/s004380050407. [DOI] [PubMed] [Google Scholar]
  18. Parcy F., Nilsson O., Busch M. A., Lee I., Weigel D. A genetic framework for floral patterning. Nature. 1998 Oct 8;395(6702):561–566. doi: 10.1038/26903. [DOI] [PubMed] [Google Scholar]
  19. Poethig R. S. Phase change and the regulation of shoot morphogenesis in plants. Science. 1990 Nov 16;250(4983):923–930. doi: 10.1126/science.250.4983.923. [DOI] [PubMed] [Google Scholar]
  20. Ratcliffe O. J., Amaya I., Vincent C. A., Rothstein S., Carpenter R., Coen E. S., Bradley D. J. A common mechanism controls the life cycle and architecture of plants. Development. 1998 May;125(9):1609–1615. doi: 10.1242/dev.125.9.1609. [DOI] [PubMed] [Google Scholar]
  21. Ratcliffe O. J., Bradley D. J., Coen E. S. Separation of shoot and floral identity in Arabidopsis. Development. 1999 Mar;126(6):1109–1120. doi: 10.1242/dev.126.6.1109. [DOI] [PubMed] [Google Scholar]
  22. Ruiz-García L., Madueño F., Wilkinson M., Haughn G., Salinas J., Martínez-Zapater J. M. Different roles of flowering-time genes in the activation of floral initiation genes in Arabidopsis. Plant Cell. 1997 Nov;9(11):1921–1934. doi: 10.1105/tpc.9.11.1921. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Schultz E. A., Haughn G. W. LEAFY, a Homeotic Gene That Regulates Inflorescence Development in Arabidopsis. Plant Cell. 1991 Aug;3(8):771–781. doi: 10.1105/tpc.3.8.771. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. 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]
  25. 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]
  26. Simon R., Igeño M. I., Coupland G. Activation of floral meristem identity genes in Arabidopsis. Nature. 1996 Nov 7;384(6604):59–62. doi: 10.1038/384059a0. [DOI] [PubMed] [Google Scholar]
  27. Weigel D., Alvarez J., Smyth D. R., Yanofsky M. F., Meyerowitz E. M. LEAFY controls floral meristem identity in Arabidopsis. Cell. 1992 May 29;69(5):843–859. doi: 10.1016/0092-8674(92)90295-n. [DOI] [PubMed] [Google Scholar]
  28. Weigel D., Meyerowitz E. M. Activation of floral homeotic genes in Arabidopsis. Science. 1993 Sep 24;261(5129):1723–1726. doi: 10.1126/science.261.5129.1723. [DOI] [PubMed] [Google Scholar]
  29. Weigel D., Nilsson O. A developmental switch sufficient for flower initiation in diverse plants. Nature. 1995 Oct 12;377(6549):495–500. doi: 10.1038/377495a0. [DOI] [PubMed] [Google Scholar]

Articles from The Plant Cell are provided here courtesy of Oxford University Press

RESOURCES