First published online July 29, 2005; 10.1104/pp.105.064287
Plant Physiology 138:2364-2373 (2005)
© 2005 American Society of Plant Biologists
ENVIRONMENTAL STRESS AND ADAPTATION
Regulation of VRN-1 Vernalization Genes in Normal and Transgenic Polyploid Wheat1
Artem Loukoianov,
Liuling Yan,
Ann Blechl,
Alexandra Sanchez and
Jorge Dubcovsky*
Department of Plant Sciences, University of California, Davis, California 95616 (A.L., L.Y., A.S., J.D.); and United States Department of Agriculture, Agricultural Research Service, Western Regional Research Center, Albany, California 94710 (A.B.)
Vernalization, the requirement of a long exposure to low temperatures to accelerate flowering, is an essential adaptation of plants to cold winters. The vernalization gene VRN-1 plays an important role in this process in diploid (Triticum monococcum) and polyploid wheat (Triticum aestivum). We have recently shown that the diploid wheat VRN-Am1 gene was similar to the Arabidopsis (Arabidopsis thaliana L. Heynh.) APETALA1 meristem identity gene. We also showed that dominant Vrn-Am1 alleles were the result of loss-of-function mutations in regulatory regions recognized by a VRN-1 repressor, likely VRN-2. This model predicts that only the dominant Vrn-1 allele will be transcribed in lines carrying both recessive and dominant alleles. Here, we confirm this prediction in young isogenic lines of hexaploid wheat carrying different dominant Vrn-A1, Vrn-B1, and Vrn-D1 alleles, and also in heterozygous VRN-1 diploid wheat plants. However, a few weeks later, transcripts from the recessive alleles were also detected in both the polyploid and heterozygous diploid spring plants. Transcription of the recessive alleles was preceded by a reduction of the transcript levels of VRN-2. These results suggest that the dominant Vrn-1 allele or a gene regulated by VRN-1 down-regulates the VRN-2 repressor facilitating the transcription of the recessive alleles in unvernalized plants. We also show here that the level of VRN-1 transcripts in early developmental stages is critical for flowering initiation. A reduction of VRN-1 transcript levels by RNA interference delayed apex transition to the reproductive stage, increased the number of leaves, and delayed heading time by 2 to 3 weeks. We hypothesize that the coordinated transcription of dominant and recessive alleles may contribute to an earlier attainment of the VRN-1 transcript level threshold required to trigger flowering initiation in polyploid wheat.
1 This work was supported by the U.S. Department of Agriculture Cooperative State Research, Education, and Extension Service, National Research Initiative (competitive grant nos. 2003–00929 and 2004–01783).
Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.064287.
* Corresponding author; e-mail jdubcovsky{at}ucdavis.edu; fax 530–752–4361.
Received April 16, 2005;
returned for revision May 4, 2005;
accepted May 9, 2005.
This article has been cited by other articles:
|
|
|
|
 
S. Sasani, M. N. Hemming, S. N. Oliver, A. Greenup, R. Tavakkol-Afshari, S. Mahfoozi, K. Poustini, H.-R. Sharifi, E. S. Dennis, W. J. Peacock, et al.
The influence of vernalization and daylength on expression of flowering-time genes in the shoot apex and leaves of barley (Hordeum vulgare).
J. Exp. Bot.,
May 1, 2009;
60(7):
2169 - 2178.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Distelfeld, G. Tranquilli, C. Li, L. Yan, and J. Dubcovsky
Genetic and Molecular Characterization of the VRN2 Loci in Tetraploid Wheat
Plant Physiology,
January 1, 2009;
149(1):
245 - 257.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
O. N. Danilevskaya, X. Meng, D. A. Selinger, S. Deschamps, P. Hermon, G. Vansant, R. Gupta, E. V. Ananiev, and M. G. Muszynski
Involvement of the MADS-Box Gene ZMM4 in Floral Induction and Inflorescence Development in Maize
Plant Physiology,
August 1, 2008;
147(4):
2054 - 2069.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. C. Preston and E. A. Kellogg
Discrete Developmental Roles for Temperate Cereal Grass VERNALIZATION1/FRUITFULL-Like Genes in Flowering Competency and the Transition to Flowering
Plant Physiology,
January 1, 2008;
146(1):
265 - 276.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Dubcovsky and J. Dvorak
Genome Plasticity a Key Factor in the Success of Polyploid Wheat Under Domestication
Science,
June 29, 2007;
316(5833):
1862 - 1866.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. Yan, D. Fu, C. Li, A. Blechl, G. Tranquilli, M. Bonafede, A. Sanchez, M. Valarik, S. Yasuda, and J. Dubcovsky
From the Cover: The wheat and barley vernalization gene VRN3 is an orthologue of FT
PNAS,
December 19, 2006;
103(51):
19581 - 19586.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. C. Preston and E. A. Kellogg
Reconstructing the Evolutionary History of Paralogous APETALA1/FRUITFULL-Like Genes in Grasses (Poaceae)
Genetics,
September 1, 2006;
174(1):
421 - 437.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Travella, T. E. Klimm, and B. Keller
RNA Interference-Based Gene Silencing as an Efficient Tool for Functional Genomics in Hexaploid Bread Wheat
Plant Physiology,
September 1, 2006;
142(1):
6 - 20.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. Trevaskis, M. N. Hemming, W. J. Peacock, and E. S. Dennis
HvVRN2 Responds to Daylength, whereas HvVRN1 Is Regulated by Vernalization and Developmental Status
Plant Physiology,
April 1, 2006;
140(4):
1397 - 1405.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
