Characterization of the maintained vegetative phase deletions from diploid wheat and their effect on VRN2 and FT transcript levels

Assaf Distelfeld, Jorge Dubcovsky

Research output: Contribution to journalArticlepeer-review


Allelic differences at the VRN1 (AP1/CAL/FRU), VRN2 (ZCCT) and VRN3 (FT) vernalization genes affect flowering time in wheat. The two maintained vegetative phase (mvp) mutants from Triticum monococcum L., previously reported as carrying a single gene (VRN1) deletion, are incapable of flowering. In this study, we show that both mvp lines have larger deletions that include the genes AGLG1, CYS, PHYC, VRN1 and possibly others. The original mvp deletions were generated in lines that lack the VRN2 gene. Therefore, to study the effect of the mvp deletions on the regulation of VRN2 we generated populations segregating for both genes simultaneously. The two mvp deletions co-segregated with the non-flowering phenotype, but surprisingly, the lines homozygous for the mvp mutations showed reduced transcript levels of both VRN2 and FT relative to the wild type. The VRN1 deletion is an unlikely cause of the down-regulation of VRN2 since VRN2 transcript levels are higher in the fall, before VRN1 is expressed, and are down-regulated by VRN1. Since both VRN2 and FT are regulated by light and photoperiod, their down-regulation in the mvp mutants might be related to the deletion of the PHYC photoreceptor. However, alternative hypotheses including combinations of other genes deleted in the mvp mutants cannot be ruled out. Until the specific gene(s) responsible for the down-regulation of VRN2 and FT and the non-flowering phenotype are precisely identified, it is premature to use these results to postulate alternative flowering models.

Original languageEnglish
Pages (from-to)223-232
Number of pages10
JournalMolecular Genetics and Genomics
Issue number3
StatePublished - Mar 2010
Externally publishedYes

Bibliographical note

Funding Information:
Acknowledgments We would like to thank Dr. Koji Morai for kindly providing us with the heterozygous lines for the mvp-1 and mvp-2 mutations. This project was supported by the National Research Initiative grants number 2007-35301-17737 and 2007-35301-18188 from the USDA National Institute of Food and Agriculture. Dr. Assaf Distelfeld was supported by a Vaadia-BARD Postdoctoral Fellowship Award No. FI-386-06. The authors thank Cindy Miguita and Mei-Yee Lau for excellent technical assistance.


  • Flowering
  • Phytochrome
  • VRN1
  • Vernalization
  • Wheat

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology


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