Cloning and characterization of a putative orthologue of the wheat vernalization (VRN1) gene in perennial wheatgrass (Agropyron cristatum)

Abstract

Flowering time is important in the adaptation of crop plants to different environments and impacts the economic value of agricultural crops. Wheatgrass is a perennial Triticeae species and one of the most important grasses for pasture and forage in temperate regions of the world. Late heading is of interest in forage crop breeding programmes. Increasing the time to heading by molecular means may be facilitated by the identification and characterization of floral genes. In addition, the characterization of orthologous genes in wheatgrass is useful for establishing genetic relationships between grasses. In this study, we characterized a wheatgrass orthologue of the hexaploid wheat VRN-A1 gene involved in the vernalization response. High sequence similarity of this gene, designated VRN-P1, to both VRN-A1 and VRN-H1 and its localization on the 5PL chromosome arm in Agropyron cristatum indicated that VRN-P1 is orthologous to VRN1 from wheat and barley. VRN-P1 retains the VRN1 exon/intron organization and encodes a MADS-box transcription factor. Phylogenetic and amino acid analyses confirmed that the isolated sequence represents VRN1. Furthermore, phylogenetic analysis of the deduced protein sequence revealed an intimate genetic relationship between VRN-P1 and VRN1 from Triticeae species.

Development and Characterization of Wheat-Agropyron cristatum Introgression Lines Induced by Gametocidal Genes and Wheat ph1b Mutant

“…By sequencing the transcriptome of a tetraploid A. cristatum accession, Zhou et al [53] found that the sequence similarity of most A. cristatum and wheat genes were greater than 95%. The synteny in homoeologous group 5 is also conserved between A. cristatum and wheat, as shown for agronomically important genes, such as the grain hardness (Ha) locus (mapped on the short arm of chromosome 5P) [54] and the vernalization (VRN-1) locus (mapped on the long arm of chromosome 5P) [55], indicating that these loci are collinear which those located on the short and long arms, respectively of chromosome 5 in each of the wheat A, B, and D genomes.…”

Analysis of Chromosome Associations during Early Meiosis in Wheat Lines Carrying Chromosome Introgressions from Agropyron cristatum

“…Particularly for homologous groups 5 and 6, comparative mapping using a set of COS molecular markers showed that most of them were located on the short or long arms of wheat chromosome group 5 and 6 and were assigned to corresponding short or long arms of A. cristatum 5P and 6P chromosomes, respectively, indicating both homology between chromosomes 5P and 6P and wheat group 5 and 6, respectively [37]. In addition, synteny between A. cristatum and wheat homologous group 5 has also been demonstrated by mapping agronomically important genes, such as the grain hardness (Ha) and the vernalization (VRN-1) loci on the short and on the long arms of chromosome 5P, respectively [36,42], showing that these loci are collinear with those located on the short and the long arms, respectively, of chromosomes 5A, 5B and 5D in wheat. Together, these results indicated that a conservation of genes exists between wheat and A. cristatum chromosomes.…”

“…In fact, these available wheat-A. cristatum addition lines allowed the location of molecular markers and genes for several important agronomic traits on specific A. cristatum chromosomes and chromosome arms [8,9,36,42]. However, no ditelosomic addition or substitution lines were previously obtained for the chromosome 5PS arm.…”