Analysis of VRN1 gene in triticale and common wheat genetic background

Resumo

In cereals, the transition from the vegetative stage to flowering is controlled in the main by the set of vernalization genes. Within these genes the most important role is played by VRN1, which encodes a MADS-box transcription factor, regulating the transition of shoot apical meristem to the reproductive phase. The level of vernalization requirement is strongly linked to the molecular structure of this gene. In this study we analyzed molecular mechanisms regulating the vernalization requirement in triticale on the basis of comparative analysis of the VRN1 locus between triticale (×Triticosecale Witt.) and common wheat (Triticum aestivum L.) genotypes. We also estimated the influence of VRN genotype on heading time and the winter hardiness of these two species. Molecular markers developed for VRN genotype detection in common wheat were successfully applied to an analysis of triticale genomic DNA. Subsequent analysis of the amplicons nucleotide sequence confirmed full similarity of the products obtained between triticale and common wheat. All winter triticale cultivars tested contained the recessive vrn-A1 allele, whereas all spring genotypes carried the dominant Vrn-A1a allele. Molecular analysis of the Vrn-B1 gene revealed the presence of the dominant Vrn-B1b allele in only one of the triticale genotypes analyzed (Legalo). The major system of determination of the vernalization requirement in triticale was transferred from common wheat without changes and is based on an alteration in the VRN1 gene promoter sequence within the A genome.