Characterising avenin-like proteins (ALPs) from albumin/globulin fraction of wheat grains by RP-HPLC, SDS-PAGE, and MS/MS peptides sequencing

NanoLC-MS/MS protein analysis on laser-microdissected wheat endosperm tissues: A comparison between aleurone, sub-aleurone and inner endosperm

Wheat kernel proteins are not homogeneously distributed throughout the endosperm. The goal of this study was to investigate the relative differences in protein composition between the aleurone, sub-aleurone and inner endosperm. Using laser microdissection followed by nanoLC-MS/MS, an innovative method combining high spatial specificity and analytical selectivity in sample-limited situations, 780 proteins were detected and classified by function. A higher proportion of gluten proteins was detected in the sub-aleurone than inner endosperm. Composition-wise, gluten from the sub-aleurone is relatively more enriched in ω-gliadins but impoverished in LMW-GS and γ-gliadins. While a basic set of albumins and globulins was detected in all three microdissected endosperm tissues, specific proteins, like puroindoline B, displayed a gradient. This study provides indications that both histological origin and relative positioning of the tissues drive the protein distribution. Knowledge of this protein distribution offers significant opportunities for the wheat manufacturing industry. Data available via ProteomeXchange, identifier PXD038743.

Germplasm characterization and SDS-PAGE analysis of caper (Capparis spinosa L.) from different provenances

BACKGROUND

Capparis spinosa L. is a typical desert plant that is resistant to high temperatures and drought, and at the same time is rich in medicinal and food values. The objective of this study is to explore the variations in nutrient composition, morphological characteristics, and SDS-PAGE patterns of caper seeds from different provenances, aiming to provide insights for the selection of superior seed provenances.

RESULTS

In this experiment, there were significant differences in the morphological characteristics and major nutritional components of caper seeds from different provenances. Seeds from the YKL (Karayagaqi Township, Yining County) and YKG (G218, KashiTown, Yining County) regions were larger in size compared to seeds from other regions. Among the four measured nutritional components, crude fat had the highest content, especially in the YKL and YKG region. The results of correlation analysis showed that crude fat was negatively correlated with soluble sugar and soluble protein but significantly positively correlated with starch content. As longitude increased from east to west, the morphological characteristics gradually increased. Based on the principal component analysis of all the parameters of the seeds, the eight provenances could be classified into three groups. HM (Hami), TGS (S202, Gaochang District, Turpan), HYW (Wubao Town, Yizhou District, Hami), TQQ (Qiquanhu Town, Turpan), and TLF (Turpan) were a group with higher soluble protein, soluble sugar, and water content. YKL and YKG were in one group, which had larger seed grains with high crude fat and starch content. AKS (Aksu) was in a separate group. The protein fractions from seeds of eight regions were extracted using Osborne fractionation method, it was found that glutelin content was the highest, while albumin content was the lowest. After these proteins were analyzed by SDS-PAGE, the electrophoretic patterns showed that the protein molecular weights were relatively small, and there were differences in protein bands among different provenances.

CONCLUSION

According to the PCA results, the eight seed provenances could be divided into three groups. There were both geographically distant ones clustered into one group, and those close to each other were also divided into one group. There were differences in seed morphology, nutrient content and SDS-PAGE profiles among the different seed sources. This difference might be caused by a combination of geographic and climatic factors. In addition, YKL and YKG were roughly selected as good seed provenances, which provided a theoretical basis for the development of C. spinosa L. germplasm resources.

Transient drought during flowering modifies the grain proteome of bread winter wheat

Drought is among the most limiting factors for sustainable agricultural production. Water shortage at the onset of flowering severely affects the quality and quantity of grain yield of bread wheat (Triticum aestivum). Herein, we measured oxidative stress and photosynthesis-related parameters upon applying transient drought on contrasting wheat cultivars at the flowering stage of ontogenesis. The sensitive cultivar (Darunok Podillia) showed ineffective water management and a more severe decline in photosynthesis. Apparently, the tolerant genotype (Odeska 267) used photorespiration to dissipate excessive light energy. The tolerant cultivar sooner induced superoxide dismutase and showed less inhibited photosynthesis. Such a protective effect resulted in less affected yield and spectrum of seed proteome. The tolerant cultivar had a more stable gluten profile, which defines bread-making quality, upon drought. Water deficit caused the accumulation of medically relevant proteins: (i) components of gluten in the sensitive cultivar and (ii) metabolic proteins in the tolerant cultivar. We propose specific proteins for further exploration as potential markers of drought tolerance for guiding efficient breeding: thaumatin-like protein, 14-3-3 protein, peroxiredoxins, peroxidase, FBD domain protein, and Ap2/ERF plus B3 domain protein.

Microbial community succession patterns and drivers of Luxiang-flavor Jiupei during long fermentation

Luxiang-flavor Baijiu is the mainstream of Baijiu production and consumption in China, and the microbial composition has a great influence on the flavor and quality of Baijiu. In this study, we combined multi-omics sequencing technology to explore the microbial composition, dynamics and metabolite changes of Luxiang-flavor Jiupei during long fermentation periods. The results showed that based on the interaction between environmental constraints and microorganisms, Jiupei microorganisms formed different ecological niches and functional differentiation, which led to the formation of Jiupei stable core microorganisms. The bacteria were mainly Lactobacillus and Acetobacter, and the fungi were mainly Kazachstani and Issatchenkia. Most bacteria were negatively correlated with temperature, alcohol and acidity, and for the fungi, starch content, reducing sugar content and temperature had the most significant effects on community succession. Macroproteomic analysis revealed that Lactobacillus jinshani had the highest relative content; microbial composition, growth changes and functions were more similar in the pre-fermentation period (0-18 days); microorganisms stabilized in the late fermentation period (24-220 days). The metabolome analysis revealed that the metabolites of the Jiupei changed rapidly from 18 to 32 days of fermentation, with a significant increase in the relative content of amino acids, peptides and analogs and a significant decrease in the relative content of sugars; the metabolites of the Jiupei changed slowly from 32 to 220 days of fermentation, with a stabilization of the content of amino acids, peptides and analogs. This work provides insights into the microbial succession and microbial drivers during the long-term fermentation of Jiupei, which have potential implications for optimizing production and improving the flavor of Baijiu.

Transcriptome and Proteome Analysis Revealed the Influence of High-Molecular-Weight Glutenin Subunits (HMW-GSs) Deficiency on Expression of Storage Substances and the Potential Regulatory Mechanism of HMW-GSs

The processing quality of wheat is affected by seed storage substances, such as protein and starch. High-molecular-weight glutenin subunits (HMW-GSs) are the major components of wheat seed storage proteins (SSPs); they are also key determinators of wheat end-use quality. However, the effects of HMW-GSs absence on the expression of other storage substances and the regulation mechanism of HMW-GSs are still limited. Previously, a wheat transgenic line LH-11 with complete deletions of HMW-GSs was obtained through introducing an exogenous gene Glu-1E^bx to the wild-type cultivar Bobwhite by transgenic approach. In this study, comparative seed transcriptomics and proteomics of transgenic and non-transgenic lines at different seed developmental stages were carried out to explore the changes in genes and proteins and the underlying regulatory mechanism. Results revealed that a number of genes, including genes related to SSPs, carbohydrates metabolism, amino acids metabolism, transcription, translation, and protein process were differentially enriched. Seed storage proteins displayed differential expression patterns between the transgenic and non-transgenic line, a major rise in the expression levels of gliadins were observed at 21 and 28 days post anthesis (DPA) in the transgenic line. Changes in expressions of low-molecular-weight glutenins (LMW-GSs), avenin-like proteins (ALPs), lipid transfer proteins (LTPs), and protease inhibitors (PIs) were also observed. In addition, genes related to carbohydrate metabolism were differentially expressed, which probably leads to a difference in starch component and deposition. A list of gene categories participating in the accumulation of SSPs was proposed according to the transcriptome and proteome data. Six genes from the MYB and eight genes from the NAC transcription families are likely important regulators of HMW-GSs accumulation. This study will provide data support for understanding the regulatory network of wheat storage substances. The screened candidate genes can lay a foundation for further research on the regulation mechanism of HMW-GSs.

The molecular basis of cereal grain proteostasis

Storage proteins deposited in the endosperm of cereal grains are both a nitrogen reserve for seed germination and seedling growth and a primary protein source for human nutrition. Detailed surveys of the patterns of storage protein accumulation in cereal grains during grain development have been undertaken, but an in-depth understanding of the molecular mechanisms that regulate these patterns is still lacking. Accumulation of storage proteins in cereal grains involves a series of subcellular compartments, a set of energy-dependent events that compete with other cellular processes, and a balance of protein synthesis and protein degradation rates at different times during the developmental process. In this review, we focus on the importance of rates in cereal grain storage protein accumulation during grain development and outline the potential implications and applications of this information to accelerate modern agriculture breeding programmes and optimize energy use efficiency in proteostasis.

RNA-Seq Analysis of Developing Grains of Wheat to Intrigue Into the Complex Molecular Mechanism of the Heat Stress Response

Heat stress is one of the significant constraints affecting wheat production worldwide. To ensure food security for ever-increasing world population, improving wheat for heat stress tolerance is needed in the presently drifting climatic conditions. At the molecular level, heat stress tolerance in wheat is governed by a complex interplay of various heat stress-associated genes. We used a comparative transcriptome sequencing approach to study the effect of heat stress (5°C above ambient threshold temperature of 20°C) during grain filling stages in wheat genotype K7903 (Halna). At 7 DPA (days post-anthesis), heat stress treatment was given at four stages: 0, 24, 48, and 120 h. In total, 115,656 wheat genes were identified, including 309 differentially expressed genes (DEGs) involved in many critical processes, such as signal transduction, starch synthetic pathway, antioxidant pathway, and heat stress-responsive conserved and uncharacterized putative genes that play an essential role in maintaining the grain filling rate at the high temperature. A total of 98,412 Simple Sequences Repeats (SSR) were identified from de novo transcriptome assembly of wheat and validated. The miRNA target prediction from differential expressed genes was performed by psRNATarget server against 119 mature miRNA. Further, 107,107 variants including 80,936 Single nucleotide polymorphism (SNPs) and 26,171 insertion/deletion (Indels) were also identified in de novo transcriptome assembly of wheat and wheat genome Ensembl version 31. The present study enriches our understanding of known heat response mechanisms during the grain filling stage supported by discovery of novel transcripts, microsatellite markers, putative miRNA targets, and genetic variant. This enhances gene functions and regulators, paving the way for improved heat tolerance in wheat varieties, making them more suitable for production in the current climate change scenario.

Contribution, Composition, and Structure of EPS by In Vivo Exposure to Elucidate the Mechanisms of Nanoparticle-Enhanced Bioremediation to Metals

Bacterial extracellular polymeric substances (EPS) have been recently found to contribute most for metal removal in nanoenhanced bioremediation. However, the mechanism by which NPs affect EPS-metal interactions is not fully known. Here, Halomonas sp. was employed to explore the role of EPS after in vivo exposure to Cd/Pb and polyvinylpyrrolidone (PVP) coated iron oxide nanoparticles (IONPs, 20 mg L^-1) for 72 h. Cd-IONPs produced the highest concentrations of EPS proteins (136.3 mg L^-1), while Cd induced the most production of polysaccharides (241.0 mg L^-1). IONPs increased protein/polysaccharides ratio from 0.2 (Cd) to 1.2 (Cd-IONPs). The increased protein favors the formation of protein coronas on IONPs surface, which would promote Cd adsorption during NP-metal-EPS interaction. FTIR analysis indicated that the coexistence of Cd and IONPs interacted with proteins more strongly than with polysaccharides. Glycosyl monomer analyses suggested mannose and glucose as target sugars for EPS complexation with metals, and IONPs reduced metal-induced changes in monosaccharide profiles. Protein secondary structures changed in all treatments, but we could not distinguish stresses induced by metals from those by IONPs. These findings provide greater understanding of the role of EPS in NP-metal-EPS interaction, providing a better underpinning knowledge for the application of NP-enhanced bioremediation.

Proteome Analysis and Epitope Mapping in a Commercial Reduced-Gluten Wheat Product

Gluten related disorders, such as coeliac disease, wheat allergy and baker's asthma are triggered by proteins present in food products made from wheat and related cereal species. The only treatment of these medical illnesses is a strict gluten-free diet; however, gluten-free products that are currently available in the market can have lower nutritional quality and are more expensive than traditional gluten containing cereal products. These constraints have led to the development of gluten-free or gluten-reduced ingredients. In this vein, a non-GMO wheat flour that purports to contain "65% less allergenic gluten" was recently brought to market. The present study aims to understand the alteration of the proteome profile of this wheat flour material. Liquid chromatography-mass spectrometry was used to investigate the proteome profile of the novel wheat flour, which was contrasted to a wheat flour control. Using both trypsin and chymotrypsin digests and a combined database search, 564 unique proteins were identified with 99% confidence. These proteins and the specific peptides used to identify them were mapped to the wheat genome to reveal the associated chromosomal regions in the novel wheat flour and the mixed wheat control. Of note, several ω- and γ-gliadins, and low-molecular weight glutenins mapping to the short arm of chromosome 1, as well as α-gliadins from the chromosome 6 short arm were absent or expressed at lower levels in the novel wheat variety. In contrast, the high-molecular weight glutenins and α-amylase/trypsin inhibitors were notably more abundant in this variety. A targeted quantitation experiment was developed using multiple reaction monitoring assays to quantify 359 tryptic and chymotryptic peptides from gluten and related allergenic proteins revealing a 33% decrease of gluten protein content in the novel wheat flour sample in comparison to mixed wheat control. However, additional mapping of known allergenic epitopes showed the presence of 53% higher allergenic peptides. Overall, the current study highlights the importance of proteomic analyses especially when complemented by sequence analysis and epitope mapping for monitoring immunostimulatory proteins.

Rising Atmospheric Temperature Impact on Wheat and Thermotolerance Strategies

Temperature across the globe is increasing continuously at the rate of 0.15–0.17 °C per decade since the industrial revolution. It is influencing agricultural crop productivity. Therefore, thermotolerance strategies are needed to have sustainability in crop yield under higher temperature. However, improving thermotolerance in the crop is a challenging task for crop scientists. Therefore, this review work was conducted with the aim of providing information on the wheat response in three research areas, i.e., physiology, breeding, and advances in genetics, which could assist the researchers in improving thermotolerance. The optimum temperature for wheat growth at the heading, anthesis, and grain filling duration is 16 ± 2.3 °C, 23 ± 1.75 °C, and 26 ± 1.53 °C, respectively. The high temperature adversely influences the crop phenology, growth, and development. The pre-anthesis high temperature retards the pollen viability, seed formation, and embryo development. The post-anthesis high temperature declines the starch granules accumulation, stem reserve carbohydrates, and translocation of photosynthates into grains. A high temperature above 40 °C inhibits the photosynthesis by damaging the photosystem-II, electron transport chain, and photosystem-I. Our review work highlighted that genotypes which can maintain a higher accumulation of proline, glycine betaine, expression of heat shock proteins, stay green and antioxidant enzymes activity viz., catalase, peroxidase, super oxide dismutase, and glutathione reductase can tolerate high temperature efficiently through sustaining cellular physiology. Similarly, the pre-anthesis acclimation with heat treatment, inorganic fertilizer such as nitrogen, potassium nitrate and potassium chloride, mulches with rice husk, early sowing, presoaking of a 6.6 mM solution of thiourea, foliar application of 50 ppm dithiothreitol, 10 mg per kg of silicon at heading and zinc ameliorate the crop against the high temperature. Finally, it has been suggested that modern genomics and omics techniques should be used to develop thermotolerance in wheat.