Molecular characterization of the allelic variation at the VRN-H2 vernalization locus in barley
Received: 02 August 2004 Accepted: 03 January 2005 DOI:
10.1007/s11032-005-0084-6 Cite this article as: Dubcovsky, J., Chen, C. & Yan, L. Mol Breeding (2005) 15: 395. doi:10.1007/s11032-005-0084-6 Abstract VRN-2 is a dominant repressor of flowering that plays a central role in the vernalization pathway of wheat. This gene is a zinc-finger/CCT domain transcription factor ( ZCCT-1) down-regulated by vernalization. In barley, there are three related and linked ZCCT genes designated VRN-H1a, b, and c. A deletion of these three genes was observed in six putative spring induced mutants from winter barley variety ‘Chikurin Ibaraki I’. However, analysis of additional molecular markers demonstrated that these deletions were originated by outcrossing with a spring barley variety carrying the natural ZCCT deletion. Hybridization of Southern blots from 84 barley varieties with a wheat ZCCT1 probe showed three or more fragments in 23 winter varieties but none in 60 out of the 61 vrn-H2 spring varieties. The vrn-H2-spring barley variety ‘Fan’ showed only the ZCCT-Hb gene, suggesting that this gene is not sufficient to determine winter growth habit in barley. We also show in this study, that the effect of VRN-H2 on flowering time completely disappears in the presence of the dominant Vrn-H1 allele in a Morex × Hordeum spontaneum segregating population. A different result was described before for the epistatic interactions between the orthologous genes in diploid wheat. We discuss the possible causes of these differences. Keywords Allelic variation Barley Induced mutants Vernalization VRN-2 ZCCT References Barrett, B., Bayram, M., Kidwell, K. 2002 Identifying AFLP and microsatellite markers for vernalization response gene Vrn-B1 in hexaploid wheat ( Triticum aestivum L.) using reciprocal mapping populations Plant Breed. 121 400 406 CrossRef Google Scholar Chen, F.Q., Foolad, M.R. 1997 Molecular organization of a gene in barley which encodes a protein similar to aspartic protease and its specific expression in nucellar cells during degeneration Plant Mol. Biol. 35 821 831 CrossRef PubMed Google Scholar Devos, K.M., Dubcovsky, J., Dvorak, J., Chinoy, C.N., Gale, M.D. 1995 Structural evolution of wheat chromosomes 4A5Aand 7B and its impact on recombination Theor. Appl. Genet. 91 282 288 CrossRef Google Scholar Dubcovsky, J., Galvez, A.F., Dvorak, J. 1994 Comparison of the genetic organization of the early salt stress response gene system in salt-tolerant Lophopyrum elongatum and salt-sensitive wheat Theor. Appl. Genet. 87 957 964 CrossRef Google Scholar Dubcovsky, J., Lijavetzky, D., Appendino, L., Tranquilli, G. 1998 Comparative RFLP mapping of Triticum monococcum genes controlling vernalization requirement Theor. Appl. Genet. 97 968 975 CrossRef Google Scholar Dvorak, J., McGuire, P.E., Cassidy, B. 1988 Apparent sources of the A genomes of wheats inferred from the polymorphism in abundance and restriction fragment length of repeated nucleotide sequences Genome 30 680 689 Google Scholar
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