The
objective
of this study is to assess the impacts of additional N fertilization on agricultural traits, flour characteristics, and noodle quality of O-free, a variety known for reduced allergy effects. With increasing fertilization rates, both culm length and spike length showed an increase, accompanied by a rise in grain nitrogen removal due to higher protein content in the grains. The leaf area index (LAI) reached its peak during the booting stage, while the canopy LAI peaked at 21 days after flowering (21-DAF). Although LAI of plant was higher in the treatments with additional nitrogen (N1 and N2) compared to the control (N0), there was no significant difference observed in canopy LAI. Chlorophyll fluorescence values were highest at 21-DAF and lowest at 35-DAF, regardless of the fertilizer rate. The dry weight of leaves and stems was highest at 7-DAF in N0 and N1 treatments, but at 21-DAF in N2 treatment. During grain filling, the nitrogen content decreased in leaves and stems, while it increased in the grains. With higher fertilization rates, there was an increase in the moisture content, flour color value, protein content, and sedimentation value of flour, whereas the particle size of flour decreased. Dough extensibility, mixing time, and protein strength showed an increase as the fertilizer rate increased, but dough stability decreased. The control exhibited the highest starch gel stability and aging, while N1 had the lowest starch swelling. Cooked noodles demonstrated increased brightness, thickness, and hardness with increasing fertilizer rate, but elasticity and viscosity showed no significant changes.

Gliadin proteins are a major component of gluten proteins and important determinants of bread-making quality by conferring the viscosity and extensibility of dough, but also present significant health problems for consumers with wheat-related diseases like celiac disease or wheat allergies. In order to solve this problem, we conducted RP-HPLC analysis to profile gliadin fractions for screening the mutants deficient in gliadins from 122 wheat doubled-haploid (DH) lines cultivated by the National Institute of Crop Science. Comparing the RP-HPLC chromatogram of 122 DH lines with those of the respective parents, we found that some peaks of omega-5 gliadin were not present in 28 DH lines. Further analysis using SDS-PAGE and A-PAGE showed that the omega-5 gliadin in the parental varieties had two to three bands, but only one band in the absent 28 DH lines. The relative expression levels of all gliadin groups in the parental and mutant lines were also examined by RP-HPLC. Our study contributes to establishing a method for the rapid screening and identification of mutants missing gliadins as major epitopes of wheat-related disease in many wheat genetic resources and breeding lines as valuable information to other researchers.

Gliadin proteins, which are a component of gluten and confer viscosity and extensibility on wheat dough, are major determinants of wheat processing suitability and also present dietary problems for consumers with celiac disease or wheat allergies. In this study, gliadin proteins of the hexaploid wheat variety ‘Chinese Spring’ (CS) and of its nullisomic-tetrasomic (NT) and ditelosomic (DT) lines missing group 1 and 6 chromosome, were analyzed using LabChip GXII Touch 24 within 1 min per sample. The chromatogram pattern analysis of gliadin proteins from group 1 aneuploid lines (N1AT1B, N1AT1D; N1BT1A, N1BT1D; N1DT1A, N1DT1B) missing 1A, 1B and 1D chromosomes respectively, from CS showed that 24, 25 and 26 sec peaks of CS, presuming to be ω5-, ω1,2- and γ- gliadins, were disappeared. The analysis of group 6 aneuploid lines (N6AT6B, N6AT6D, 6AL; N6BT6A, 6BL; N6DT6B, 6DL) missing 6A, 6AS; 6B, 6BS; 6D, 6DS chromosomes respectively, from CS indicated that 22, 25 and 26 sec peaks of CS, presuming to be α-/β- gliadins, were disappeared. The results of this study will be applicable to high-throughput screening of wheat gliadin mutants among wheat breeding lines and genetic resources for the development of allergy - reduced wheat.

The ω5-gliadins are the major allergens in wheat-dependent excise-induced anaphylaxis (WDEIA). In this study, SDS-PAGE analysis was used to assign the ω5-gliadins (Gli-B1) alleles in thirty two Korean wheat cultivars, compared with eleven standard wheat cultivars for Gli-B1a~m alleles. These results were reconfirmed with their complementary Glu-B3 low-molecular-weight glutenin subunits alleles tightly linked with Gli-B1 locus revealed with 2-DGE in our previous study. As a result, one Gli-B1b, four Gli-B1d, two Gli-B1f, six Gli-B1m and nineteen Gli-B1h varieties were identified. This is the first report on revealing the Gli-B1 alleles in Korean wheat cultivars and represents valuable basic data on wheat allergy, relationship between gliadin and wheat quality, and development of hypo-allergenic wheat.