Allelic Variation for Prolamins in Spanish Durum Wheat Landraces and Its Relationship with Quality Traits

Abstract

Wheat landraces are currently being explored mainly as a source of allelic variation related to crop resilience and low-input adaptation. Characterization of their high- and low-molecular weight glutenin subunits can aid breeders to select as donor local materials those ensuring good end-use properties in the derived elite cultivars. By using protein electrophoretic methods, we have determined the prolamin allelic profile of 116 Spanish durum wheat landraces. Their quality properties (as defined by grain protein content, sodium dodecyl sulfate (SDS) sedimentation volume and mixograph behavior) have also been assessed. The study has identified six novel glutenin alleles plus some other rare alleles some of which have been associated with improved durum wheat quality. Most of the novel variation detected needs to be characterized in a wider sample of varieties to establish any eventual beneficial effect on functional quality. Further analysis of the quality properties associated to specific allele combinations of Glu-A3, Glu-B3, and Glu-A1 has disclosed some clues on the influence on quality of certain non-allelic interactions between these main prolamin-encoding loci. Some of the landraces, showing outstanding values for the gluten quality parameters analyzed, might be directly used by farmers interested in the cultivation of traditional varieties for specialized food markets.

Assessment of the Glutenin Subunits Diversity in a Durum Wheat (T. turgidum ssp. durum) Collection from Morocco

“…This rare allele was originally found in an emmer wheat accession (CI-12213) by Cherdouh et al [22] and later in some Spanish landraces [19] and in some durum wheat landraces from Iran [9], even at lower frequencies than in this study. Chacón et al [19] found that this allele may be associated with lower gluten strength, whereas Hernández-Espinosa et al [9] associated this allele with a higher gluten strength, extensibility and bread-making quality. However, it has to be noted that both studies reported preliminary results and that more work is needed in order to define the effects of this allele on quality traits.…”

“…Within the HMW-GS group, at the Glu-A1 locus, only one landrace showed a non-null allele, which is relatively normal, as most modern durum wheat materials typically exhibit the null allele at this locus [35][36][37][38]. However, other sets of durum wheat landraces have shown higher frequencies for Glu-A1 alleles different from the Glu-A1c null allele [19,20,39]. The contribution of the non-null Glu-A1 alleles to durum wheat quality traits is still not well defined.…”

“…The contribution of the non-null Glu-A1 alleles to durum wheat quality traits is still not well defined. Some studies indicate that these alleles probably do not have a significant effect on durum wheat gluten quality [10,19,40], whereas other studies clearly show that their presence enhances gluten strength and extensibility [41][42][43]. The Glu-B1 locus showed the highest number of alleles (7).…”

“…In contrast, the LMW-GS are encoded by genes located at the Glu-A3, Glu-B3 and Glu-B2 loci, located on the short arm of the homoeologous group 1 chromosome [10,17]. Several studies have shown that variation in the HMW-or LMW-GS alleles is associated with differences in the gluten and end-use quality [9,[18][19][20][21]. For this reason, the study of the glutenins' composition is fundamental to understanding and characterizing gluten quality.…”

“…For this reason, the study of the glutenins' composition is fundamental to understanding and characterizing gluten quality. Durum wheat landraces exhibit a wide variability of this class of proteins, and, in the past years, several sets of landraces from different Mediterranean countries have been characterized for their HMW-and LMW-GS profile [10,19,20,[22][23][24].…”