Wheat Grain Protein Research Articles

The proportion of nitrate in leaf nitrogen, but not changes in root growth, are associated with decreased grain protein in wheat under elevated [CO2

The atmospheric CO2 concentration ([CO2]) is increasing and predicted to reach ∼550ppm by 2050. Increasing [CO2] typically stimulates crop growth and yield, but decreases concentrations of nutrients, such as nitrogen ([N]), and therefore protein, in plant tissues and grains. Such changes in grain composition are expected to have negative implications for the nutritional and economic value of grains. This study addresses two mechanisms potentially accountable for the phenomenon of elevated [CO2]-induced decreases in [N]: N uptake per unit length of roots as well as inhibition of the assimilation of nitrate (NO3−) into protein are investigated and related to grain protein. We analysed two wheat cultivars from a similar genetic background but contrasting in agronomic features (Triticum aestivum L. cv. Scout and Yitpi). Plants were field-grown within the Australian Grains Free Air CO2 Enrichment (AGFACE) facility under two atmospheric [CO2] (ambient, ∼400ppm, and elevated, ∼550ppm) and two water treatments (rain-fed and well-watered). Aboveground dry weight (ADW) and root length (RL, captured by a mini-rhizotron root growth monitoring system), as well as [N] and NO3− concentrations ([NO3−]) were monitored throughout the growing season and related to grain protein at harvest. RL generally increased under e[CO2] and varied between water supply and cultivars. The ratio of total aboveground N (TN) taken up per RL was affected by CO2 treatment only later in the season and there was no significant correlation between TN/RL and grain protein concentration across cultivars and [CO2] treatments. In contrast, a greater percentage of N remained as unassimilated [NO3−] in the tissue of e[CO2] grown crops (expressed as the ratio of NO3− to total N) and this was significantly correlated with decreased grain protein. These findings suggest that e[CO2] directly affects the nitrate assimilation capacity of wheat with direct negative implications for grain quality.

The Gsp-1 genes encode the wheat arabinogalactan peptide

Western blotting, ELISA and 1H-NMR spectroscopy showed that RNAi down-regulation of the wheat Gsp-1 gene resulted in reduced contents of both arabinogalactan peptide (AGP) and grain softness protein (GSP-1) in mature wheat grains confirming that these components are encoded by the same gene. A small increase in grain hardness and decrease in the viscosity of aqueous extracts of the transgenic lines also indicated small effects on functional properties. Immunolocalisation using a novel wheat AGP monoclonal antibody in conjunction with confocal microscopy showed that the major form of AGP which was eliminated in knockout lines is located within the cell, probably in the vacuole, and not in the plasma membrane or cell wall. However, clear localisation of the AGP epitope to the plasma membrane was observed in both control and transgenic lines and probably resulted from the presence of one or more separate forms of arabinogalactan protein. The existence of such additional form(s) was also indicated by 1H-NMR spectroscopy which showed that the ratio of arabinose to galactose differed between the control and transgenic lines.

Responses of glutamine synthetase activity and gene expression to nitrogen levels in winter wheat cultivars with different grain protein content

Glutamine synthetase (GS) plays a central role in plant nitrogen (N) metabolism, which improves crops grain protein content. A pot experiment in field condition was carried out to evaluate GS expression and activity, and grain protein content in high (Wanmai16) and low grain protein (Loumai24) wheat cultivars under two N levels (0.05 and 0.15 g N kg−1 soil). High nitrogen (HN) resulted in significant increases in GS1 and GS2 expression at 10 days after anthesis (DAA), and higher GS activity during the entire grain filling stage. HN also significantly increased yield, grain protein content and protein fraction (except for glutenin of Luomai24) in two wheat cultivars, which indicated that it increased grain yield and protein content by improving nitrogen metabolism. Wanmai16 showed higher grain protein content, gliadin and glutenin content, and had higher expression level of GS2 both in flag leaves and grains at early grain filling stage. However, Luomai24 had greater yield and higher expression level of GS1. The difference expression of GS2 and GS1 genes indicates they had various contributions to the accumulation of protein and starch in wheat grains, respectively. The results suggest that GS2 would be serving as a potential breeding target for improving wheat quality.

Dynamics of amino acid carbon and nitrogen and relationship with grain protein in wheat under elevated CO2 and soil warming

The interactive effects of elevated atmospheric CO2 concentration ([CO2]) (700μmoll−1) and increased soil temperature (+2.4°C) on source-sink amino acid carbon (C) and nitrogen (N) dynamics and their relations to the concentration of grain protein components in winter wheat were investigated in greenhouse. Compared to the plants grown under ambient [CO2] (400μmoll−1) the contribution of N translocated after anthesis to the grain decreased, however, the total amount of N accumulated in the grain after anthesis increased in the plants grown under elevated [CO2]. Exposure of the plants to elevated [CO2] enhanced C allocation towards leaf at anthesis, but the allocation of leaf C and N as amino acid C and N was reduced by the combination of elevated [CO2] and soil warming. In addition, the amino acid C and N in the grain were also significantly decreased by the combined elevated [CO2] and soil warming treatment. The grain protein concentration correlated linearly with grain amino acid C but not with grain amino acid N. Collectively, the results indicated that modification of C and N metabolisms in the source and sink under future climate change scenarios may significantly decreased the protein concentration, and, thereby, the quality of wheat grain.

Variations in grain lipophilic phytochemicals, proteins and resistance to Fusarium spp. growth during grain storage as affected by biological plant protection with Aureobasidium pullulans (de Bary)

Modern agriculture relies on an integrated approach, where chemical treatment is reduced to a minimum and replaced by biological control that involves the use of active microorganisms. The effect of the antagonistic yeast-like fungus Aureobasidium pullulans on proteins and bioactive compounds (alkylresorcinols, sterols, tocols and carotenoids) in winter wheat grain and on the colonization of wheat kernels by fungal microbiota, mainly Fusarium spp. pathogens, was investigated. Biological treatment contributed to a slight increase contents of tocols, alkylresorcinols and sterols in grain. At the same time, the variation of wheat grain proteins was low and not significant. Application of A. pullulans enhanced the natural yeast colonization after six months of grain storage and inhibited growth of F. culmorum pathogens penetrating wheat kernel. This study demonstrated that an integrated approach of wheat grain protection with the use of the yeast-like fungus A. pullulans reduced kernel colonization by Fusarium spp. pathogens and increased the content of nutritionally beneficial phytochemicals in wheat grain without a loss of gluten proteins responsible for baking value.

Influence of tillage systems and nitrogen management on grain yield, grain protein and nitrogen-use efficiency in UK spring wheat

SUMMARYEffects of soil tillage systems and nitrogen (N) fertilizer management on spring wheat yield components, grain yield and N-use efficiency (NUE) were evaluated in contrasting weather of 2013 and 2014 on a clay soil at the Royal Agricultural University's Harnhill Manor Farm, Cirencester, UK. Three tillage systems – conventional plough tillage (CT), high intensity non-inversion tillage (HINiT) and low intensity non-inversion tillage (LINiT) for seedbed preparation – were compared at four rates of N fertilizer (0, 70, 140 and 210 kg N/ha). Responses to the effects of the management practices were strongly influenced by weather conditions and varied across seasons. Grain yields were similar between LINiT and CT in 2013, while CT produced higher yields in 2014. Nitrogen fertilization effects also varied across the years with no significant effects observed on grain yield in 2013, while in 2014 applications up to 140 kg N/ha increased yield. Grain protein ranged from 10·1 to 14·5% and increased with N rate in both years. Nitrogen-use efficiency ranged from 12·6 to 49·1 kg grain per kg N fertilizer and decreased as N fertilization rate increased in both years. There was no tillage effect on NUE in 2013, while in 2014 NUE under CT was similar to LINiT and higher than HINiT. The effect of tillage and N fertilization on soil moisture and soil mineral N (SMN) fluctuated across years. In 2013, LINiT showed significantly higher soil moisture than CT, while soil moisture did not differ between tillage systems in 2014. Conventional tillage had significantly higher SMN at harvest time in 2014, while no significant differences on SMN were observed between tillage systems in 2013. These results indicate that LINiT can be used to produce similar spring wheat yield to CT on this particular soil type, if a dry cropping season is expected. Crop response to N fertilization is limited when soil residual N is higher, while in conditions of lower residual SMN, a higher N supply is needed to increase yield and improve grain protein content.

Effect of Organic and Inorganic Farming on Nutrients and Fatty Acid Composition of Soybean, Wheat and Chickpea

A field experiment was conducted during kharif and rabi seasons of 2011–13 to evaluate the effect of application of farm yard manure (FYM), recommended doses of fertilizers (RDF) and their combination on the nutritional quality of soybean (Glycine max L. Merr.), chickpea (Cicer arietinum L.) and wheat (Triticum aestivum L.). Total soluble protein in soybean and wheat grains was higher on combined application of FYM+RDF, whereas high total soluble proteins was observed in chickpea grown with FYM alone. Maximum free amino acid content in soybean, wheat and chickpea was observed in treatment with FYM alone. Higher linoleic and linolenic acids were observed in combined treatments of RDF+FYM in soybean and chickpea seeds, and highest oleic acid was observed in treatment with integrated nutrient management (INM). Significant increase in tryptophan was observed in soybean in combined treatment of FYM+RDF, whereas significantly higher methionine was observed in chickpea seeds in FYM treatment. High total soluble sugars was observed in chickpea grown with FYM @10 tonnes ha−1, whereas higher total sugars and sucrose was observed in soybean grown with FYM @ 5 tonnes ha−1+ 50%RDF.

Effects of Se Application on Se Accumulation and Transformation and Content of Gross Protein and Mineral Elements in Wheat Grain

Effects of Se Application on Se Accumulation and Transformation and Content of Gross Protein and Mineral Elements in Wheat Grain

Proteomic Approach to Identify Nuclear Proteins in Wheat Grain.

The nuclear proteome of the grain of the two cultivated wheat species Triticum aestivum (hexaploid wheat; genomes A, B, and D) and T. monococcum (diploid wheat; genome A) was analyzed in two early stages of development using shotgun-based proteomics. A procedure was optimized to purify nuclei, and an improved protein sample preparation was developed to efficiently remove nonprotein substances (starch and nucleic acids). A total of 797 proteins corresponding to 528 unique proteins were identified, 36% of which were classified in functional groups related to DNA and RNA metabolism. A large number (107 proteins) of unknown functions and hypothetical proteins were also found. Some identified proteins may be multifunctional and may present multiple localizations. On the basis of the MS/MS analysis, 368 proteins were present in the two species, and in two stages of development, some qualitative differences between species and stages of development were also found. All of these data illustrate the dynamic function of the grain nucleus in the early stages of development.

Genome-, Transcriptome- and Proteome-Wide Analyses of the Gliadin Gene Families in Triticum urartu.

Gliadins are the major components of storage proteins in wheat grains, and they play an essential role in the dough extensibility and nutritional quality of flour. Because of the large number of the gliadin family members, the high level of sequence identity, and the lack of abundant genomic data for Triticum species, identifying the full complement of gliadin family genes in hexaploid wheat remains challenging. Triticum urartu is a wild diploid wheat species and considered the A-genome donor of polyploid wheat species. The accession PI428198 (G1812) was chosen to determine the complete composition of the gliadin gene families in the wheat A-genome using the available draft genome. Using a PCR-based cloning strategy for genomic DNA and mRNA as well as a bioinformatics analysis of genomic sequence data, 28 gliadin genes were characterized. Of these genes, 23 were α-gliadin genes, three were γ-gliadin genes and two were ω-gliadin genes. An RNA sequencing (RNA-Seq) survey of the dynamic expression patterns of gliadin genes revealed that their synthesis in immature grains began prior to 10 days post-anthesis (DPA), peaked at 15 DPA and gradually decreased at 20 DPA. The accumulation of proteins encoded by 16 of the expressed gliadin genes was further verified and quantified using proteomic methods. The phylogenetic analysis demonstrated that the homologs of these α-gliadin genes were present in tetraploid and hexaploid wheat, which was consistent with T. urartu being the A-genome progenitor species. This study presents a systematic investigation of the gliadin gene families in T. urartu that spans the genome, transcriptome and proteome, and it provides new information to better understand the molecular structure, expression profiles and evolution of the gliadin genes in T. urartu and common wheat.

Predicting the yield and quality of winter wheat grown on calcareous chernozem in the lower Don Region

Long-term studies have revealed a system of indicators for predicting the yield of winter wheat grown on a calcareous chernozem. It has been established that the prediction and integrated assessment of the yield and quality of grain should be performed with consideration for the balance of macro- and micronutrients in the grain and the above-ground biomass of plants. It has been shown that the contents of protein and gluten in winter wheat grain are mainly determined by the supply of plants with nitrogen and its balance with Mn, Р, Fe, Zn, and K. Possibility of predicting the contents of macro- and micronutrients in wheat grain from the chemical composition of plants at the shooting stage has been revealed.

Using 7 cm immobilized pH gradient strips to determine levels of clinically relevant proteins in wheat grain extracts.

The aim of the work was to test a relatively simple proteomics approach based on phenol extraction and two-dimensional gel electrophoresis (2-DE) with 7 cm immobilized pH gradient strips for the determination of clinically relevant proteins in wheat grain. Using this approach, 157 2-DE spots were quantified in biological triplicate, out of which 55 were identified by matrix-assisted laser desorption/ionization – time of flight tandem mass spectrometry. Clinically relevant proteins associated with celiac disease, wheat dependent exercise induced anaphylaxis, baker’s asthma, and food allergy, were detected in 24 2-DE spots. However, alcohol-soluble gliadins were not detected with this approach. The comparison with a recent quantitative study suggested that gel-based and gel-free proteomics approaches are complementary for the detection and quantification of clinically relevant proteins in wheat grain.

Message from the editors: coeliac disease focused issue.

Message from the editors: coeliac disease focused issue.

Post-flowering nitrate uptake in wheat is controlled by N status at flowering, with a putative major role of root nitrate transporter NRT2.1.

In bread wheat (Triticum aestivum L.), the simultaneous improvement of both yield and grain protein is difficult because of the strong negative relationship between these two traits. However, some genotypes deviate positively from this relationship and this has been linked to their ability to take up nitrogen (N) during the post-flowering period, regardless of their N status at flowering. The physiological and genetic determinants of post-flowering N uptake relating to N satiety are poorly understood. This study uses semi-hydroponic culture of cv. Récital under controlled conditions to explore these controls. The first objective was to record the effects of contrasting N status at flowering on post-flowering nitrate (NO3 -) uptake under non-limiting NO3 - conditions, while following the expression of key genes involved in NO3 - uptake and assimilation. We found that post-flowering NO3 - uptake was strongly influenced by plant N status at flowering during the first 300–400 degree-days after flowering, overlapping with a probable regulation of nitrate uptake exerted by N demand for growth. The uptake of NO3 - correlated well with the expression of the gene TaNRT2.1, coding for a root NO3 - transporter, which seems to play a major role in post-flowering NO3 - uptake. These results provide a useful knowledge base for future investigation of genetic variability in post-flowering N uptake and may lead to concomitant gains in both grain yield and grain protein in wheat.

Influences of one-year red clover ley management on subsequent cereal crops

A field experiment of one-year leys was established at Moreton-in-Marsh, Gloucestershire, UK (NGR SP 217 323) with six combinations of red clover, perennial ryegrass and cocksfoot and two fallow control plots in May 2010 to determine the effects of ‘cut and remove’ cropping three times or ‘cut and mulch’ once annually on biomass yield and nitrogen (N) accumulation. The effect of fertility building leys on grain yield and quality were studied in two subsequent cereal crops. There was no evidence during the ley fertility building phase that red clover monoculture (RC) had a strong positive effect on grass productivity when in mixtures, irrespective of the cutting system. In cut/mulch, the red clover/ryegrass/cocksfoot (RCRGCF) mixture had least dry matter and N yields of all red clover-based leys. In the arable phase, all red clover-based leys gave subsequent winter wheat grain yields comparable to those of best conventional management. The cutting system had an effect only on red clover/ryegrass (RCRG) and ryegrass (RG). Maximum grain yield of winter wheat occurred after mulching of RCRG. For spring wheat, the preceding sown species or the cutting system had no effect on grain yield, partly due to preceding wet weather. RC consistently had greater grain protein in both subsequent winter and spring wheat. Growing short-term RC as a fertility-building forage crop could significantly improve grain protein content in both winter and spring wheat, regardless of management. RC could potentially be of economic importance, especially in low input stockless farming, where N supplementation may be limited.

Effect of stabilized-n fertilizer (SNT) use on yield attributes, yield, nutrient uptake and quality of wheat (Triticum aestivumL.)

Field experiments were conducted during rabi 2010–11 and 2011–12 with wheat as a test crop using different SNT urea at Fertilizer Research Station, Uttari Pura of Chandra Shekhar Azad University of Agriculture & Technology, Kanpur. The present work was undertaken to study the effect of different SNT urea on yield, nutrients uptake and quality of wheat (PBW-343). The use of different SNT urea (46%) at 100% local rate significantly increased grain and straw yield of wheat over T3. Urea (46%) at 100% local rate highest yield grain 5460 kg/ha and straw 9349 kg/ha were recorded with urea (46%) SNT-C (46%) at 100% local rate. The yield attributes increased with the use of different SNT urea over plain urea and highest value was noted with T6. The NPK uptake and per cent protein in wheat grain also significantly increased with the application of different SNT urea over plain urea and higher values were recorded with T6.

Genetic dissection of interaction between wheat protein and starch using three mapping populations

Protein and starch are important factors in determining wheat end-use quality and yield. However, these two traits are negatively correlated. So in order to dissect the genetic relationship between grain protein content (GPC) and grain starch content (GSC) at QTL/gene level, three mapping populations were used at three locations in 2 years. The QTLs for GPC and GSC were analyzed by unconditional and conditional QTL mappings. Thirteen QTLs were detected for GPC by each of the conditional and unconditional methods of QTL analyses. For GSC, seven and nine QTLs, respectively, were detected using unconditional and conditional QTL analyses methods. Of these QTLs, there was only one major QTL detected for GPC using unconditional QTL analysis. For GSC, two major QTLs were detected through each of the conditional and unconditional QTL mapping methods. Seven QTLs with minor effect on GSC were identified for GPC (Qgpc2A-12, Qgpc6D-3, Qgpc1D-15, Qgpc2D-23, Qgpc2D-31, Qgpc5B-19, and Qgpc4B-7). Four QTLs were found for GSC, named Qgsc1D-1, Qgsc4A-9, Qgsc7B-15, and Qgsc7D1-2, which had minor influence on GPC. The major QTL Qgsc7B-15 can directly be used for improving the GSC in molecular marker-assisted breeding. QTLs detected in the present study could possibly be used in simultaneous improvement of grain protein and starch content in wheat.

Reduction of toxic gliadin content of wholegrain bread by the enzyme caricain

Increasingly the number of individuals being diagnosed with some form of sensitivity to the proteins in wheat grains represents a cause for concern. Currently, the treatment is dietary withdrawal of gluten, but commercial gluten-free bread presents some undesirable properties. The objective of this study has been to assess the ability of the enzyme caricain (from papaya latex) to detoxify gliadin in whole wheat flour and develop bread suitable for coeliacs and gluten intolerant individuals. Ion exchange chromatography was used to enrich the caricain in papaya latex and an enzyme-linked immunosorbent assay test kit was used for the analysis of gliadin residues in the baked bread. The partially purified enzyme was found to be more effective in reducing gliadin content than the crude papain and the resultant loaves had acceptable crumb and crust characteristics. Caricain appears to be capable of detoxifying gliadin and has the potential to mitigate the problems confronting coeliacs.

Effects of Disused Battery on Contents of Protein and Nucleic Acid during the Germination of Wheat Seeds

The aim was to study the effect of extract of disused battery on wheat germination. The germination characteristics such as germination rate, germinating, germination index, vigor index, and content changes of protein and nucleic acid in wheat grain were determined by germination bed method. The results showed that the extract concentration of disused battery affected wheat germination. With the increase of extract concentration of disused battery, the germination rate, germinating, germination index, vigor index and content of nucleic acid gradually dropped, only protein content added.

Grain yield, starch, protein, and nutritional element concentrations of winter wheat exposed to enhanced UV-B during different growth stages

In order to alleviate the damage of UV-B on plants, it is important to determine at which growth stages are plants more sensitive to enhanced UV-B. The objective of the study was to evaluate the effects of UV-B on wheat yield and quality during different growth stages. Enhanced UV-B during heading, flowering and the whole growth stages (UCK, from seedling to grain filling) decreased yield by 6.6, 4.4 and 9.6%, respectively. Protein content in grain was decreased by enhanced UV-B during flowering and UCK over the control. Amylose, amylopectin and total starch content were not affected by UV-B treatments. UCK treatment resulted in a decrease of nitrogen (N), phosphorus (P) and iron (Fe) concentrations, while zinc (Zn) and manganese (Mn) concentrations increased. Enhanced UV-B during tillering, heading and flowering stages reduced Fe concentration, but increased Mn, copper (Cu) and Zn (except for flowering) concentrations. The results indicated that the changes in wheat yield and quality induced by enhanced UV-B during the whole growth stage were probably from the effects of UV-B radiation during heading and flowering stages. Therefore, to better defend the damage of UV-B to wheat, some methods should be undertaken during heading and flowering stages.