A major quantitative trait locus for cold-responsive gene expression is linked to frost-resistance gene <i>Fr-A2</i> in common wheat

Abstract

Low temperature induces expression of Cor (cold-responsive)/Lea (late embryogenesis-abundant) gene family members through C-repeat binding factor (CBF) transcription factors in common wheat. However, the relationship between the genetic loci controlling cold-responsive gene expression and freezing tolerance is unclear. In expression quantitative trait locus (eQTL) analysis, accumulated transcripts of Cor/Lea and CBF genes were quantified in recombinant inbred lines derived from a cross between two common wheat cultivars with different levels of freezing tolerance. Four eQTLs controlling five cold-responsive genes were found, and the major eQTL with the greatest effect was located on the long arm of chromosome 5A. At least the 1D and 5A eQTLs played important roles in development of freezing tolerance in common wheat. The chromosomal location of the 5A eQTL, controlling four cold-responsive genes, coincided with a region homoeologous to a frost-tolerance locus (Fr-Am2) reported as a CBF cluster region in einkorn wheat. The 5A eQTL plays a significant role through Cor/Lea gene expression in cold acclimation of wheat. In addition, our results suggest that one or more CBF copies at the Fr-2 region positively regulate other copies, which might amplify the positive effects of the CBF cluster on downstream Cor/Lea gene activation.

The expression ofCBFgenes atFr-2locus is associated with the level of frost tolerance in Bulgarian winter wheat cultivars

“…However, the pattern was different and the transcript abundance in this cultivar was up to 20- and 50-fold lower than that in Russalka and Milena, respectively ( Figure 2 (A)). Similar results for the tolerant winter-hardy cultivar Mir808 have been obtained by Motomura et al.,[ 32 ] who reported a transient increase in TaCBFA15 expression with a maximum between the fourth and sixth hours of the LT, resembling the pattern obtained for Milena in the present study. On the other hand, our results for CS disagree with those of Motomura et al.,[ 32 ] who found no increase in the transcript abundance of TaCBF15 in the leaf tissue of this cultivar during LT course treatment at 4 °C.…”

Mapping QTLs for cold tolerance at germination and the early seedling stage in rice (Oryza sativaL.)

“…[ 33 ] These results suggest that chromosome 11 possesses several major QTLs controlling cold tolerance at germination and the early seedling stages in rice. It has been well known that rice chromosome 11 has synteny with chromosome 5A of wheat and 5H of barley,[ 49 ] which possess the cluster of FR2 (Frost Resistance 2) and CBF genes [ 50,51 ]. A detailed QTL analysis using more closely linked markers and a more powerful substitution mapping is required for further dissection of these QTL regions.…”

Copy number and haplotype variation at the VRN-A1 and central FR-A2 loci are associated with frost tolerance in hexaploid wheat

“…The second frost tolerance locus, FR2, was mapped ~30 cM proximal to VRN1 on homoeologous group 5 chromosomes of both wheat and barley and is associated with frost tolerance and expression of the COLD REGULATED (COR) gene, Cor14b (Tóth et al 2003;Vágújfalvi et al 2003;McIntosh et al 2004;Francia et al 2004;Båga et al 2007;Motomura et al 2013). In hexaploid wheat, the differential CBF expression detected between frost-sensitive and frost-tolerant varieties was tightly associated with the FR-A2 locus (Vágújfalvi et al 2005).…”

“…In hexaploid wheat, the differential CBF expression detected between frost-sensitive and frost-tolerant varieties was tightly associated with the FR-A2 locus (Vágújfalvi et al 2005). QTL for frost tolerance have been identified in several independent studies at this locus (Båga et al 2007;Motomura et al 2013). The FR-A m 2 locus from diploid wheat Triticcum monococcum (A m genome related to the A genome of polyploid wheat) was later found to comprise 11 tandemly duplicated CBF genes clustered closely together on chromosome 5A m (Miller et al 2006).…”