English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Background    Triticum araraticum  and  Triticum timopheevii  are tetraploid species of the Timopheevi group. The former includes both winter and spring forms with a predominance of winter forms, whereas  T. timopheevii  is considered a spring species. In order to clarify the origin of the spring growth habit in  T. timopheevii , allelic variability of the  VRN-1  gene was investigated in a set of accessions of both tetraploid species, together with the diploid species  Ae. speltoides , presumed donor of the G genome to these tetraploids.    Results  The promoter region of the  VRN-A1  locus in all studied tetraploid accessions of both  T. araraticum  and  T. timopheevii  represents the previously described allele  VRN-A1f  with a 50 bp deletion near the start codon. Three additional alleles were identified namely,  VRN-A1f-del ,  VRN-A1f-ins  and  VRN-A1f-del/ins,  which contained large mutations in the first (1 st ) intron of  VRN-A1.  The first allele, carrying a deletion of 2.7 kb in a central part of intron 1, occurred in a few accessions of  T. araraticum  and no accessions of  T. timopheevii.  The  VRN-A1f-ins  allele, containing the insertion of a 0.4 kb MITE element about 0.4 kb upstream from the start of intron 1, and allele  VRN-A1f-del/ins  having this insertion coupled with a deletion of 2.7 kb are characteristic only for  T. timopheevii.  Allelic variation at the  VRN-G1  locus includes the previously described allele  VRN-G1a  (with the insertion of a 0.2 kb MITE in the promoter) found in a few accessions of both tetraploid species. We showed that alleles  VRN-A1f-del  and  VRN-G1a  have no association with the spring growth habit, while in all accessions of  T. timopheevii  this habit was associated with the dominant  VRN-A1f-ins  and  VRN-A1f-del/ins  alleles. None of the  Ae. speltoides  accessions included in this study had changes in the promoter or 1 st  intron regions of  VRN-1  which might confer a spring growth habit. The  VRN-1  promoter sequences analyzed herein and downloaded from databases have been used to construct a phylogram to assess the time of divergence of  Ae. speltoides  in relation to other wheat species.    Conclusions  Among accessions of  T. araraticum , the preferentially winter predecessor of  T. timopheevii , two large mutations were found in both  VRN-A1  and  VRN-G1  loci ( VRN-A1f-del  and  VRN-G1a ) that were found to have no effect on vernalization requirements. Spring tetraploid  T. timopheevii  had one  VRN-1  allele in common for two species ( VRN-G1a ), and two that were specific ( VRN-A1f-ins ,  VRN-A1f-del/ins ). The latter alleles include mutations in the 1 st  intron of  VRN-A1  and also share a 0.4 kb MITE insertion near the start of intron 1. We suggested that this insertion resulted in a spring growth habit in a progenitor of  T. timopheevii  which has probably been selected during subsequent domestication. The phylogram constructed on the basis of the  VRN-1  promoter sequences confirmed the early divergence (~3.5 MYA) of the ancestor(s) of the B/G genomes from  Ae. speltoides .    Electronic supplementary material  The online version of this article (doi:10.1186/s12870-016-0925-y) contains supplementary material, which is available to authorized users.

The occurrence of spring forms in tetraploid Timopheevi wheat is associated with variation in the first intron of the VRN-A1 gene