Fingerprinting of wheat protein profiles for improved distinction between wheat cultivars and species

Darina Pronin,Katharina A. Scherf,Sabrina Geisslitz,Andreas Börner

doi:10.1002/cche.10323

Abstract

AbstractBackground and objectivesWheat protein composition is commonly characterized by reversed‐phase (RP)‐HPLC‐UV after extraction of albumins/globulins, gliadins (ω5‐, ω1,2‐, α‐, and γ‐gliadins), and glutenins (high‐ and low‐molecular‐weight glutenin subunits). However, this traditional classification does not consider the individual distribution of peaks, resulting in loss of information on protein fingerprints. We developed a new approach to peak integration and evaluated its suitability to differentiate between wheat cultivars and species.FindingsIntegration events were performed every 20 s, and the relative proportions of the peaks were calculated. We compared the traditional and new integration methods on two sample sets, the first comprising 60 common wheat cultivars from 1891 to 2010 and the second comprising 40 common wheat, spelt, durum wheat, emmer, and einkorn cultivars. The new integration method performed better in differentiating old and modern common wheat cultivars and was also applicable to different wheat species.ConclusionsUnique cultivars were identified that stood out because of their protein composition. Four samples warrant further research to identify the specific proteins that are responsible for the differences.Significance and noveltyThe new integration allowed us to map the cultivar‐ and species‐specific fingerprints, identify cultivars with exceptional protein composition, and group similar cultivars.

Highlights

Wheat belongs to the Triticeae of the Poaceae grass family and is subdivided into different species according to ploidy levels
The traditional way of peak integration for cereal proteins as described in Wieser et al (1998) is as follows: The albumin/ globulin fraction is not subdivided further, while the gliadin and glutenin fractions are subdivided into ω5, ω1,2, α, and γ-gliadins as well as ωb-gliadins, HMW-glutenin subunits (GS), and LMW-GS, respectively (Figure 1)
A principal component analysis (PCA) was performed in order to reduce the dimensionality of the data set and to see possible changes between old and modern wheat cultivars

Summary

Introduction

Wheat belongs to the Triticeae of the Poaceae grass family and is subdivided into different species according to ploidy levels. Each gluten protein type contains different numbers of single proteins, for example, 7 ω-gliadins, 23 α-gliadins, 13 γ-gliadins, 5 HMW-GS, and 22 LMW-GS as identified in the wheat cultivar Butte 86 (Dupont, Vensel, Tanaka, Hurkman, & Altenbach, 2011) These numbers and the protein quantities vary depending on the genotype (G), the environment (E), and the G × E interaction (Geisslitz, Longin, Scherf, & Koehler, 2019; Shewry et al, 2010; Ward et al, 2008). Wheat protein composition is commonly characterized by reversed-phase (RP)-HPLC-UV after extraction of albumins/globulins, gliadins (ω5-, ω1,2-, α-, and γ-gliadins), and glutenins (high- and low-molecular-weight glutenin subunits) This traditional classification does not consider the individual distribution of peaks, resulting in loss of information on protein fingerprints. Significance and novelty: The new integration allowed us to map the cultivar- and species-specific fingerprints, identify cultivars with exceptional protein composition, and group similar cultivars

Objectives

Methods

Results

Conclusion