Allelic variation and differential expression of VRN‐A1 in durum wheat genotypes varying in the vernalization response

Abstract

The purpose of this research was to study the effect of vernalization on flowering time in thirty accessions of Triticum turgidum spp. durum. To this end, screening of allelic variation at VRN‐1 loci was carried out using PCR‐based markers and DNA sequencing, and gene expression analysis was performed in two and four developmental stages, with and without cold treatment. In non‐vernalized plants, average days to flowering ranged from 34 to 99 days and only one accession was observed to remain at the vegetative stage. Three accessions were found to accelerate flowering after cold treatment. At VRN‐A1 locus, three alleles previously characterized, Vrn‐A1b, Vrn‐A1c and vrn‐A1, were detected. No polymorphisms at VRN‐B1 locus were observed. The differences in vernalization response among the genotypes studied could be explained by allelic variation and VRN‐A1 transcript levels. Variability in flowering time and sensitivity to vernalization in a collection of durum wheat, both potentially useful to the development of new varieties, were observed. This information is key to directing breeding cultivars for adaptation.

Allelic Variation at the Vernalization Response (Vrn-1) and Photoperiod Sensitivity (Ppd-1) Genes and Their Association With the Development of Durum Wheat Landraces and Modern Cultivars

“…The winter allele vrn-A1 was only identified in two landraces, but it was not present in the present set of modern cultivars. This result is in agreement with the clear preponderance of spring dominant alleles at the Vrn-A1 gene found previously in improved durum wheat varieties from Argentina, CIMMYT, France, Italy, and Hungary (Basualdo et al, 2015). The allele Vrn-A1a, found previously in durum wheat varieties from Russia (Muterko et al, 2016b) was not present in the germplasm analyzed here.…”

Genomic analysis of Spanish wheat landraces reveals their variability and potential for breeding

“…The evolution of spring-habit cultivars from winter-habit accessions played a key role in the postdomestication spread of wheat. However, studies on the major vernalization gene VRN1 have been mostly limited to hexaploid wheat species and very few reports from tetraploid species can be found in the literature [48,49]. None of the durum wheat accessions characterized here showed the Vrn-A1a allele described in spring-habit hexaploid wheat varieties, which is in accordance with what has been found in other studies [50,51].…”

“…Vernalization genes are the main determinants of the growth habit (i.e., winter or spring) in temperate cereals, and by affecting the vegetative to reproductive transition, these genes are involved in the ability of wheat plants to adapt to a wide range of environments [48]. The evolution of spring-habit cultivars from winter-habit accessions played a key role in the postdomestication spread of wheat.…”

Genomic Regions Associated with the Control of Flowering Time in Durum Wheat

“…This is in line with what can be expected since accessions carrying the recessive Vrn allele would not be able to flower under those conditions. Previous studies suggested Vrn-1 to be essential in the control of winter flowering types of common wheat [35][36][37], and durum wheat [22,27,[38][39][40][41][42]. However, results of the present research show only partial agreement with the literature, with a clear role of Vrn1 confirmed only when no cold temperatures occur (see PhEnv3 and 4 in Table 1), but substantially no effect in PhEnv where weak or strong vernalization requirements can be met (see PhEnv1 and 2 in Table 1).…”