VRN1 genes variability in tetraploid wheat species with a spring growth habit

Abstract

BackgroundVernalization genes VRN1 play a major role in the transition from vegetative to reproductive growth in wheat. In di-, tetra- and hexaploid wheats the presence of a dominant allele of at least one VRN1 gene homologue (Vrn-A1, Vrn-B1, Vrn-G1 or Vrn-D1) determines the spring growth habit. Allelic variation between the Vrn-1 and vrn-1 alleles relies on mutations in the promoter region or the first intron. The origin and variability of the dominant VRN1 alleles, determining the spring growth habit in tetraploid wheat species have been poorly studied.ResultsHere we analyzed the growth habit of 228 tetraploid wheat species accessions and 25 % of them were spring type. We analyzed the promoter and first intron regions of VRN1 genes in 57 spring accessions of tetraploid wheats. The spring growth habit of most studied spring accessions was determined by previously identified dominant alleles of VRN1 genes. Genetic experiments proof the dominant inheritance of Vrn-A1d allele which was widely distributed across the accessions of Triticum dicoccoides. Two novel alleles were discovered and designated as Vrn-A1b.7 and Vrn-B1dic. Vrn-A1b.7 had deletions of 20 bp located 137 bp upstream of the start codon and mutations within the VRN-box when compared to the recessive allele of vrn-A1. So far the Vrn-A1d allele was identified only in spring accessions of the T. dicoccoides and T. turgidum species. Vrn-B1dic was identified in T. dicoccoides IG46225 and had 11 % sequence dissimilarity in comparison to the promoter of vrn-B1. The presence of Vrn-A1b.7 and Vrn-B1dic alleles is a predicted cause of the spring growth habit of studied accessions of tetraploid species. Three spring accessions T. aethiopicum K-19059, T. turanicum K-31693 and T. turgidum cv. Blancal possess recessive alleles of both VRN-A1 and VRN-B1 genes. Further investigations are required to determine the source of spring growth habit of these accessions.ConclusionsNew allelic variants of the VRN-A1 and VRN-B1 genes were identified in spring accessions of tetraploid wheats. The origin and evolution of VRN-A1 alleles in di- and tetraploid wheat species was discussed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0924-z) contains supplementary material, which is available to authorized users.

Origin and Distribution of the VRN-A1 Exon 4 and Exon 7 Haplotypes in Domesticated Wheat Species

“…The first is associated with the divergence of Vrn-A1a.1, Vrn-A1e and Vrn-A1i alleles in the population of tetraploid wheat carrying the Ex4C.f/7C haplotype. It is likely that this population is T. dicoccum, since these alleles were not observed in T. dicoccoides ( [12,25,26], this study). The second event is related to the presence of multiple copies of VRN-A1 in the population of hexaploid wheat with the Ex4C.m/7T haplotype following the divergence of the VRN-A1 Ex4T/7T copy.…”

“…In contrast, this haplotype was frequent in hexaploid wheat and was identified in all five species analyzed here. Almost all VRN-A1 alleles carrying mutations within the promoter region and intron-1 are characterized by the intact exon 7, Ex7C haplotype (Table 2), with the exception of the Vrn-A1c (type IL369) and Vrn-A1j alleles, previously identified in hexaploid wheat ( [23], GenBank: KU738894) and were not found in tetraploid species ( [12,25,26], here). [20] were characterized by the intact exon 7 of VRN-A1, confirming the Ex7C haplotype of VRN-D4.…”

INDEL variation in the regulatory region of the major flowering time gene LanFTc1 is associated with vernalization response and flowering time in narrow‐leafed lupin (Lupinus angustifolius L.)

“…The largest and most widely published allelic series identified to date involves VRN‐1 , a MADS‐box transcription factor that is orthologous to APETALA1 in Arabidopsis (Yan et al, ) and that is involved in maintaining down‐regulation of floral repressors following vernalization within members of the Poaceae family (A. Chen & Dubcovsky, ). Within the promoter and intronic regions, a staggering number of INDELs ranging in size from 20 to 6,850 bp, in addition to a single SNP, have been identified in the A, B, D, and G genomes of various diploid, tetraploid, and hexaploid wild and domestic wheats and their progenitors (Fu et al, ; Golovnina, Kondratenko, Blinov, & Goncharov, ; Konopatskaia, Vavilova, Kondratenko, Blinov, & Goncharov, ; Milec, Tomková, Sumíková, & Pánková, ; Muterko, Balashova, Cockram, Kalendar, & Sivolap, ; Santra, Santra, Allan, Campbell, & Kidwell, ; Shcherban, Efremova, & Salina, ; Takumi, Koyamam, Fujiwara, & Kobayashi, ; Yan et al, ; Zhang, Gao, Wang, Chen, & Cui, ), plus the H genome of barley ( Hordeum vulgare L.; Fu et al, ). Our study also adds to others in Arabidopsis (Liu et al, ; Schwartz et al, ), perennial ryegrass ( Lolium perenne ; Skøt et al, ), and wheats and barley (F. Chen et al, ; Yan et al, ) showing that FT orthologues have similarly been a common target for the evolution of natural flowering time variation in a range of plant families.…”

Computational plant bioscience at BGRS\SB-2016: introductory note

“…In this important avenue of study, this Special Issue starts with two articles investigating the genetics of wheat, one of the most important food stocks in the world [1, 2]. Both works center on the function of VRN1 (Vernalization) gene.…”

“…Both works center on the function of VRN1 (Vernalization) gene. The paper by Irina Konopatskaia and colleagues “ VRN1 genes variability in tetraploid wheat species with a spring growth habit” considers association of the growth habits of 228 tetraploid wheat species and allelic variants of VRN1 genes [1]. In “The occurrence of spring forms in tetraploid Timopheevi wheat is associated with variation in the first intron of the VRN-A1 gene,” Shcherban and co-authors discuss the promoter region of the VRN-A1 gene in T. araraticum and T. timopheevii tetraploid species [2].…”