title: The CArG-box located upstream from the transcriptional start of wheat vernalization gene VRN1 is not necessary for the vernalization response.
abstract: In diploid wheat (Triticum monococcum), and likely in other Triticeae species, the VRN1 gene is essential for the initiation of the reproductive phase, and therefore, a detailed characterization of its regulatory regions is required to understand this process. A CArG-box (MADS-box-binding site) identified in the VRN1 promoter upstream from the transcription initiation site has been proposed as a critical regulatory element for the vernalization response. This hypothesis was supported by the genetic linkage between CArG-box natural deletions and dominant Vrn1 alleles for spring growth habit and by physical interactions with VRT2, a MADS-box protein proposed as a putative flowering repressor regulated by vernalization. Here, we describe a T. monococcum accession with a strong vernalization requirement and a 48-bp deletion encompassing the CArG-box in the VRN1 promoter. Genetic analyses of 2 segregating populations confirmed that this VRN1 allele is completely linked with a strong winter growth habit (vrn-A(m)1b). Transcript levels of the VRN1 allele with the 48-bp deletion were very low in unvernalized plants and increased during vernalization to levels similar to those detected in other wild-type vrn-A(m)1 alleles. Taken together, these results indicate that the CArG-box found upstream of the VRN1 transcription initiation site is not essential for the vernalization response.
authors.affiliation: Instituto de Recursos Biológicos, INTA, Hurlingham, Buenos Aires, Argentina.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Pidal
authors.forename: Liuling
authors.initials: L
authors.lastname: Yan
authors.forename: Daolin
authors.initials: D
authors.lastname: Fu
authors.forename: Fengqiu
authors.initials: F
authors.lastname: Zhang
authors.forename: Gabriela
authors.initials: G
authors.lastname: Tranquilli
authors.forename: Jorge
authors.initials: J
authors.lastname: Dubcovsky
mesh_terms: D000483:Alleles; D001483:Base Sequence; D003433:Crosses, Genetic; D017343:Genes, Plant; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics*; D024363:Transcription Initiation Site; D014908:Triticum / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors