Validation of the VRN-H2/VRN-H1 epistatic model in barley reveals that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity

Péter Szucs, Jeffrey S. Skinner, Ildikó Karsai, Alfonso Cuesta-Marcos, Kale G. Haggard, Ann E. Corey, Tony H.H. Chen, Patrick M. Hayes

Research output: Contribution to journalArticle

93 Citations (Scopus)

Abstract

The epistatic interaction of alleles at the VRN-H1 and VRN-H2 loci determines vernalization sensitivity in barley. To validate the current molecular model for the two-locus epistasis, we crossed homozygous vernalization-insensitive plants harboring a predicted "winter type" allele at either VRN-H1 (Dicktoo) or VRN-H2 (Oregon Wolfe Barley Dominant), or at both VRN-H (Calicuchima-sib) loci and measured the flowering time of unvernalized F2 progeny under long-day photoperiod. We assessed whether the spring growth habit of Calicuchima-sib is an exception to the two-locus epistatic model or contains novel "spring" alleles at VRN-H1 (HvBM5A) and/or VRN-H2 (ZCCT-H) by determining allele sequence variants at these loci and their effects relative to growth habit. We found that (a) progeny with predicted "winter type" alleles at both VRN-H1 and VRN-H2 alleles exhibited an extremely delayed flowering (i.e. vernalization-sensitive) phenotype in two out of the three F2 populations, (b) sequence flanking the vernalization critical region of HvBM5A intron 1 likely influences degree of vernalization sensitivity, (c) a winter habit is retained when ZCCT-Ha has been deleted, and (d) the ZCCT-H genes have higher levels of allelic polymorphism than other winterhardiness regulatory genes. Our results validate the model explaining the epistatic interaction of VRN-H2 and VRN-H1 under long-day conditions, demonstrate recovery of vernalization-sensitive progeny from crosses of vernalization-insensitive genotypes, show that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity, and provide molecular markers that are accurate predictors of "winter vs spring type" alleles at the VRN-H loci.

Original languageEnglish
Pages (from-to)249-261
Number of pages13
JournalMolecular Genetics and Genomics
Volume277
Issue number3
DOIs
Publication statusPublished - Mar 1 2007

Keywords

  • BM5
  • Cereal
  • Hordeum vulgare
  • HvVRT-2
  • Triticeae
  • VRN-1
  • VRN-2
  • VRN1
  • VRN2

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics

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