Skip to main content
PMC home page
The Plant Cell logoLink to The Plant Cell
. 1995 Sep;7(9):1485–1499. doi: 10.1105/tpc.7.9.1485

UNUSUAL FLORAL ORGANS Controls Meristem Identity and Organ Primordia Fate in Arabidopsis.

M D Wilkinson 1, G W Haughn 1
PMCID: PMC160975  PMID: 12242408

Abstract

A novel gene that is involved in regulating flower initiation and development has been identified in Arabidopsis. This gene has been designated UNUSUAL FLORAL ORGANS (UFO), with five corresponding nuclear recessive alleles designated ufo[middot]1 to ufo[middot]5. Under short day-length conditions, ufo homozygotes generate more coflorescences than do the wild type, and coflorescences often appear apical to the first floral shoot, resulting in a period of inflorescence development in which regions of floral and coflorescence shoots are produced alternately. ufo enhances the phenotype of weak leafy alleles, and the double mutant Ufo-1 Apetala1-1 produces only coflorescence-like shoots, suggesting that these two genes control different aspects of floral initiation. Floral development was also altered in Ufo plants. Ufo flowers have an altered organ number in all whorls, and organs in the first, second, and third whorls exhibit variable homeotic transformations. Ufo single and double mutant phenotypes suggest that the floral changes result from reduction in class B floral homeotic gene expression and fluctuations in the expression boundaries of class C function and FLO10. Surprisingly, in situ hybridization analysis revealed no obvious differences in expression pattern or level in developing Ufo flowers compared with that of the wild type for any class B or C gene studied. We propose that UFO acts in concert with known floral initiation genes and regulates the domains of floral homeotic gene function.

Full Text

The Full Text of this article is available as a PDF (3.0 MB).

Selected References

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

  1. Bowman J. L., Sakai H., Jack T., Weigel D., Mayer U., Meyerowitz E. M. SUPERMAN, a regulator of floral homeotic genes in Arabidopsis. Development. 1992 Mar;114(3):599–615. doi: 10.1242/dev.114.3.599. [DOI] [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. Bowman J. L., Smyth D. R., Meyerowitz E. M. Genetic interactions among floral homeotic genes of Arabidopsis. Development. 1991 May;112(1):1–20. doi: 10.1242/dev.112.1.1. [DOI] [PubMed] [Google Scholar]
  4. Clark S. E., Running M. P., Meyerowitz E. M. CLAVATA1, a regulator of meristem and flower development in Arabidopsis. Development. 1993 Oct;119(2):397–418. doi: 10.1242/dev.119.2.397. [DOI] [PubMed] [Google Scholar]
  5. 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]
  6. 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]
  7. Hensel L. L., Nelson M. A., Richmond T. A., Bleecker A. B. The fate of inflorescence meristems is controlled by developing fruits in Arabidopsis. Plant Physiol. 1994 Nov;106(3):863–876. doi: 10.1104/pp.106.3.863. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. 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]
  9. Huijser P., Klein J., Lönnig W. E., Meijer H., Saedler H., Sommer H. Bracteomania, an inflorescence anomaly, is caused by the loss of function of the MADS-box gene squamosa in Antirrhinum majus. EMBO J. 1992 Apr;11(4):1239–1249. doi: 10.1002/j.1460-2075.1992.tb05168.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Ingram G. C., Goodrich J., Wilkinson M. D., Simon R., Haughn G. W., Coen E. S. Parallels between UNUSUAL FLORAL ORGANS and FIMBRIATA, genes controlling flower development in Arabidopsis and Antirrhinum. Plant Cell. 1995 Sep;7(9):1501–1510. doi: 10.1105/tpc.7.9.1501. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. 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]
  12. Jack T., Brockman L. L., Meyerowitz E. M. The homeotic gene APETALA3 of Arabidopsis thaliana encodes a MADS box and is expressed in petals and stamens. Cell. 1992 Feb 21;68(4):683–697. doi: 10.1016/0092-8674(92)90144-2. [DOI] [PubMed] [Google Scholar]
  13. 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]
  14. 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]
  15. Levin J. Z., Meyerowitz E. M. UFO: an Arabidopsis gene involved in both floral meristem and floral organ development. Plant Cell. 1995 May;7(5):529–548. doi: 10.1105/tpc.7.5.529. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Ma H. The unfolding drama of flower development: recent results from genetic and molecular analyses. Genes Dev. 1994 Apr 1;8(7):745–756. doi: 10.1101/gad.8.7.745. [DOI] [PubMed] [Google Scholar]
  17. Meyerowitz E. M. Flower development and evolution: new answers and new questions. Proc Natl Acad Sci U S A. 1994 Jun 21;91(13):5735–5737. doi: 10.1073/pnas.91.13.5735. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. 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]
  19. Schultz E. A., Pickett F. B., Haughn G. W. The FLO10 Gene Product Regulates the Expression Domain of Homeotic Genes AP3 and PI in Arabidopsis Flowers. Plant Cell. 1991 Nov;3(11):1221–1237. doi: 10.1105/tpc.3.11.1221. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. 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]
  21. Suiter K. A., Wendel J. F., Case J. S. LINKAGE-1: a PASCAL computer program for the detection and analysis of genetic linkage. J Hered. 1983 May-Jun;74(3):203–204. doi: 10.1093/oxfordjournals.jhered.a109766. [DOI] [PubMed] [Google Scholar]
  22. 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]
  23. 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]
  24. Weigel D., Meyerowitz E. M. The ABCs of floral homeotic genes. Cell. 1994 Jul 29;78(2):203–209. doi: 10.1016/0092-8674(94)90291-7. [DOI] [PubMed] [Google Scholar]
  25. Yanofsky M. F., Ma H., Bowman J. L., Drews G. N., Feldmann K. A., Meyerowitz E. M. The protein encoded by the Arabidopsis homeotic gene agamous resembles transcription factors. Nature. 1990 Jul 5;346(6279):35–39. doi: 10.1038/346035a0. [DOI] [PubMed] [Google Scholar]

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

RESOURCES