Gene-ecology of durum wheat HMW glutenin reflects their diffusion from the center of origin

M Janni,U Bonas,G Visioli,A A D Dahab,D Pignone,S Cadonici,A Ceriotti,A Grasso,N Marmiroli

doi:10.1038/s41598-018-35251-4

Abstract

The production of many food items processed from wheat grain relies on the use of high gluten strength flours. As a result, about 80% of the allelic variability in the genes encoding the glutenin proteins has been lost in the shift from landraces to modern cultivars. Here, the allelic variability in the genes encoding the high molecular weight glutenin subunits (HMW-GSs) has been characterized in 152 durum wheat lines developed from a set of landraces. The allelic composition at the two Glu-1 loci (Glu-A1 and -B1) was obtained at both the protein and the DNA level. The former locus was represented by three alleles, of which the null allele Glu-A1c was the most common. The Glu-B1 locus was more variable, with fifteen alleles represented, of which Glu-B1b (HMW-GSs 7 + 8), -B1d (6 + 8) and -B1e (20 + 20) were the most frequently occurring. The composition of HMW-GSs has been used to make inferences regarding the diffusion and diversification of durum wheat. The relationships of these allelic frequencies with their geographical distribution within the Mediterranean basin is discussed in terms of gene-ecology.

Highlights

Wheat is the world’s third most important cereal crop (FAOSTAT 2014, http://faostat3.fao.org) with durum wheat representing about 5% of global wheat production[1]
This paper aims at increase the knowledge on durum wheat domestication and diffusion by analyzing high molecular weight glutenin subunits (HMW-GSs) diversity in a set of durum wheat landraces representative of the diversity of this crop
The set of HMW-GSs detected in each of the 152 entries is reported in Suppl

Summary

Introduction

Wheat is the world’s third most important cereal crop (FAOSTAT 2014, http://faostat3.fao.org) with durum wheat (used primarily for the production of pasta) representing about 5% of global wheat production[1]. The cooking quality of pasta is highly dependent on the flour’s protein content, and in particular on the strength of the gluten[2], a visco-elastic mass that can be extracted from wheat flour and in which the storage proteins gliadins and glutenins are the main component[3,4]. The allelic forms of the high molecular weight glutenin subunits (HMW-GSs) are along with LMW major determinant of gluten strength These subunits are encoded by the Glu-1 loci, which map to the long arms of the homeologous group 1 chromosomes[6,7,8]. Cases where ambiguity remained after this analysis were resolved using a PCR approach[35]

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