Unravelling drought and salinity stress responses in barley genotypes: physiological, biochemical, and molecular insights

In the face of escalating environmental challenges, understanding crop responses to abiotic stress is pivotal for sustainable agriculture. The present study meticulously investigates the intricate interplay between drought and salinity stress in barley (Hordeum vulgare L.). Employing three distinct barley genotypes-Traveller, Prunella, and Zahna-we scrutinize their physiological, biochemical, and molecular adaptations under stress conditions. Our findings underscore genotype-specific responses, unravelling the multifaceted mechanisms that govern stress tolerance. Chlorophyll content, a vital indicator of photosynthetic efficiency, exhibits significant variations across genotypes. Salinity stress induces a decline in chlorophyll levels, while drought stress triggers a more nuanced response. Stomatal conductance, a key regulator of water loss, also diverges among the genotypes. Traveller displays remarkable stomatal closure under drought, conserving water, whereas Prunella and Zahna exhibit contrasting patterns. Antioxidant enzyme activities, crucial for combating oxidative stress, fluctuate significantly. Activities of superoxide dismutase (SOD) and catalase (CAT) surge under salinity stress, while drought predominantly impacts SOD. Gene expression profiling reveals genotype-specific signatures, with stress-responsive genes modulating adaptive pathways. Correlation analyses revealed the intricate interplay of the physiological and biochemical parameters. Genotype-specific adaptations, coupled with dynamic physiological and molecular responses, underscore the plasticity of barley's stress tolerance mechanisms. Throughout the study, the Zahna genotype demonstrated notable tolerance in terms of performance. These insights hold promise for breeding resilient cultivars, bolstering food security in an increasingly unpredictable climate. By deciphering the barley stress symphony, we contribute to the harmonious orchestration of sustainable agricultural practices.

The Ethiopian snack food ('Kolo'): Existing knowledge and research directions on processing practices, quality and consumption

'Kolo' is an Ethiopian well-roasted and dehulled barely snack food eaten alone or mixed with other roasted grains with a relatively long shelf life. It is an ancient and staple Ethiopian snack food that is being introduced around the globe. Traditionally, Kolo has been prepared by Ethiopian mothers. However, there is a scarcity of documented information about the nutritional profile, consumption status and effect of processing conditions on quality of Kolo. Therefore, the aim of this review is to access the indigenous processing practices, consumption status and the effect of processing conditions in quality of Kolo. The review discussed in detail the raw materials, processing steps, nutritional status, anti-nutritional factors, digestability and functional properties of Kolo from publications from the last thirty years. Due to the high temperature processing condition, the presence of acrylamide is highly likely and this may affect the safety of Kolo. The anti-nutritional factors in Kolo may affect the nutritional quality of Kolo due to the inaccessibility of nutrients. This information could have a significant contribution for future researchers, policy makers, society and producers. In conclusion, there is a need to get more tangible information about the quality and safety of Kolo through well designed scientific research to safeguard the wellbeing of the society.

The Evolution, Expression Patterns, and Domestication Selection Analysis of the Annexin Gene Family in the Barley Pan-Genome

Plant annexins constitute a conserved protein family that plays crucial roles in regulating plant growth and development, as well as in responses to both biotic and abiotic stresses. In this study, a total of 144 annexin genes were identified in the barley pan-genome, comprising 12 reference genomes, including cultivated barley, landraces, and wild barley. Their chromosomal locations, physical-chemical characteristics, gene structures, conserved domains, and subcellular localizations were systematically analyzed to reveal the certain differences between wild and cultivated populations. Through a cis-acting element analysis, co-expression network, and large-scale transcriptome analysis, their involvement in growth, development, and responses to various stressors was highlighted. It is worth noting that HvMOREXann5 is only expressed in pistils and anthers, indicating its crucial role in reproductive development. Based on the resequencing data from 282 barley accessions worldwide, genetic variations in thefamily were investigated, and the results showed that 5 out of the 12 identified HvMOREXanns were affected by selection pressure. Genetic diversity and haplotype frequency showed notable reductions between wild and domesticated barley, suggesting that a genetic bottleneck occurred on the annexin family during the barley domestication process. Finally, qRT-PCR analysis confirmed the up-regulation of HvMOREXann7 under drought stress, along with significant differences between wild accessions and varieties. This study provides some insights into the genome organization and genetic characteristics of the annexin gene family in barley at the pan-genome level, which will contribute to better understanding its evolution and function in barley and other crops.

Exploring the dynamics of bioactive metabolites changes in barley grains (Hordeum vulgare L.) during roasting: Insights from UPLC-QqQ-MS/MS analysis combined to chemometrics

This investigation delves into the dynamic metabolic shifts within barley grains during the roasting process, employing UPLC-QqQ-MS/MS analysis. The complex spectrum of metabolites before and after roasting is revealed. The resulting data, unveils substantial transformations in chemical composition during roasting. A total of 62 chromatographic peaks spanning phenolic compounds, flavones, Millard Reaction Products, amino acids, lignans, vitamins, folates, and anthocyanins were annotated. Leveraging UPLC-QqQ-MS/MS analysis, we scrutinized the intricate metabolite profile before and after roasting where the roasting process was found to trigger dynamic changes across diverse metabolite classes particularly Millard Reaction Products, produced through the Maillard reaction, with dihydro-5-methyl-5H-cyclopentapyrazine, maltol and hydroxy maltol emerging as discerning markers of roasting progression. Amino acids and sugars showed degradation, while beta-glucan, a signature barley sugar, experienced notable decline. Folate derivatives witnessed pronounced reduction, aligning with the heat sensitivity of folates. Harnessing the power of multivariate data analysis, the consequences of roasting materialize through distinct clusters in PCA and OPLS-DA plots. Noteworthy, roasting duration governs the trajectory of metabolic divergence, culminating in the identification of roasting-specific markers. Epigallocatechin, procyanidin B, 10-HCO-H4 folate, and hordatine A emerge as pivotal discriminators. Orthogonal Projection to Latent Structure (OPLS) analysis linked anti-inflammatory activity with 30-min, 1-hour, and 1.5-hour roasted samples, with hordatine B in addition to some Millard Reaction Products being correlated with pro-inflammatory marker downregulation.. This study encapsulates the intricate metabolic metamorphosis ignited by roasting in barley grains, offering a holistic comprehension of their potential health-enhancing attributes. Key metabolites act as poignant indicators of these transformations, substantiating the complex interplay between roasting and the barley grain metabolome.

A New Functional Wheat Flour Flatbread (Bazlama) Enriched with High-β-Glucan Hull-Less Barley Flour

Although the Med-Diet is a healthy diet model, it is affected by current dietary habits. Therefore, new foods with improved nutritional value should be developed to respond to the needs of people following the Med-Diet. This study was focused on developing high-β-glucan flat bread (bazlama) with a relatively lower GI. A bread wheat (cv. Tosunbey) flour was enriched with the flour of a high-β-glucan-content hull-less barley (cv. Chifaa) flour (15, 30, 45 and 60%) to develop a functional bazlama. The nutritional and technological properties of bazlama samples enriched with barley flour were compared with the ones produced from bread wheat. All of the barley flour-enriched bazlama samples had higher yellowness values (b*) than the control (both crumb and crust), which is generally preferred by the consumers. Texture results indicated that bazlama samples became harder with the increase in barley flour supplementation level. The results showed that 3 g of β-glucan can be provided from the barley flour-enriched bazlama samples (at 45 and 60% levels), and this is the limit to carry health claims. The bazlama samples enriched with barley flour were richer in Mg, K, Mn, Fe, and Zn minerals than the control (100% Tosunbey flour). While the glycemic index (GI) of commercial bread wheat and Tosunbey bazlama samples were high (88.60% and 79.20%, respectively), GI values of the bazlama samples enriched with 60% (64.73) and 45% barley flour (68.65) were medium. The lower GI values of barley flour-enriched bazlama samples are probably due to the higher β-glucan contents of the bazlama samples. Additionally, as the barley flour supplementation level of the bazlama samples increased, the phenolics and antioxidant capacities of free and bound extracts increased compared to bread wheat bazlama. The results indicated that hull-less barley (cv. Chifaa) with high β-glucan content may be utilized at relatively higher levels (45 and 60%) to produce bazlama with improved nutritional properties.

HvGSK1.1 Controls Salt Tolerance and Yield through the Brassinosteroid Signaling Pathway in Barley

Brassinosteroids (BRs) are a class of plant steroid hormones that are essential for plant growth and development. BRs control important agronomic traits and responses to abiotic stresses. Through the signaling pathway, BRs control the expression of thousands of genes, resulting in a variety of biological responses. The key effectors of the BR pathway are two transcription factors (TFs): BRASSINAZOLE RESISTANT 1 (BZR1) and BRI1-EMSSUPPRESSOR 1 (BES1). Both TFs are phosphorylated and inactivated by the Glycogen synthase kinase 3 BRASSINOSTEROID INSENSITIVE2 (BIN2), which acts as a negative regulator of the BR pathway. In our study, we describe the functional characteristics of HvGSK1.1, which is one of the GSK3/SHAGGY-like orthologs in barley. We generated mutant lines of HvGSK1.1 using CRISPR/Cas9 genome editing technology. Next Generation Sequencing (NGS) of the edited region of the HvGSK1.1 showed a wide variety of mutations. Most of the changes (frameshift, premature stop codon, and translation termination) resulted in the knock-out of the target gene. The molecular and phenotypic characteristics of the mutant lines showed that the knock-out mutation of HvGSK1.1 improved plant growth performance under salt stress conditions and increased the thousand kernel weight of the plants grown under normal conditions. The inactivation of HvGSK1.1 enhanced BR-dependent signaling, as indicated by the results of the leaf inclination assay in the edited lines. The plant traits under investigation are consistent with those known to be regulated by BRs. These results, together with studies of other GSK3 gene members in other plant species, suggest that targeted editing of these genes may be useful in creating plants with improved agricultural traits.

HvBGlu3, a GH1 β-glucosidase enzyme gene, negatively influences β-glucan content in barley grains

KEY MESSAGE

HvBGlu3, a β-glucosidase enzyme gene, negatively influences β-glucan content in barley grains by mediating starch and sucrose metabolism in developing grains. Barley grains are rich in β-glucan, an important factor affecting end-use quality. Previously, we identified several stable marker-trait associations (MTAs) and novel candidate genes associated with β-glucan content in barley grains using GWAS (Genome Wide Association Study) analysis. The gene HORVU3Hr1G096910, encoding β-glucosidase 3, named HvBGlu3, is found to be associated with β-glucan content in barley grains. In this study, conserved domain analysis suggested that HvBGlu3 belongs to glycoside hydrolase family 1 (GH1). Gene knockout assay revealed that HvBGlu3 negatively influenced β-glucan content in barley grains. Transcriptome analysis of developing grains of hvbglu3 mutant and the wild type indicated that the knockout of the gene led to the increased expression level of genes involved in starch and sucrose metabolism. Glucose metabolism analysis showed that the contents of many sugars in developing grains were significantly changed in hvbglu3 mutants. In conclusion, HvBGlu3 modulates β-glucan content in barley grains by mediating starch and sucrose metabolism in developing grains. The obtained results may be useful for breeders to breed elite barley cultivars for food use by screening barley lines with loss of function of HvBGlu3 in barley breeding.

Interaction and binding mechanism of ovalbumin with cereal phenolic acids: improved structure, antioxidant activity, emulsifying and digestion properties for potential targeted delivery systems

Ovalbumin (OVA) has been considered as a nutrient carrier for bioactive, which has high nutrition value and multiple properties. Recently, proteins-phenolic acids composite delivery systems have received widespread attention. Therefore, this research aimed to investigate the interaction between OVA and cereal phenolic acids (CPA) to establish delivery systems for bioactive. Spectroscopy results have found that CPA generated complexes with OVA, causing the microenvironment changes of OVA. Ferulic acid (FA), p-coumaric acid (CA), vanillic acid (VA), syringic acid (SY), sinapic acid (SI), and protocatechuic acid (PA) not only quenched the intrinsic fluorescence of OVA, but also altered protein microenvironment. Further investigation showed these complexes were formed by static quenching mode, while hydrogen bond and hydrophobic interaction were dominant binding forces. Meanwhile, the interaction decreased α-helix contents and increased β-sheet contents, leading to conformational changes in OVA. Besides, OVA/CPA complexes displayed an increase in hydrophobicity with a reduce in free-SH. After combination with FA, SY, CA, VA, SI, PA, it was found that all formed complexes had superior solubility, emulsifying and antioxidant activities than native OVA. Among them, OVA-PA exhibited the highest emulsifying activity index and emulsion stability index values (36.4 ± 0.39 m2/g and 60.4 ± 0.94 min) and stronger antioxidant activities. Finally, the combination with phenolic acids further improved the digestion efficiency in vitro of OVA. The OVA-CPA complexes showed improved properties for excellent delivery systems. Overall, OVA-CPA complexes could be a good carrier for bioactive, which provided valuable avenues in target delivery system application.

Differences in Ratio of Carbon Stable Isotopes among Barley Grain Milling Fractions with Various Concentrations of Beta-Glucans

The grains of three barley varieties were milled and sieved to obtain respective milling fractions with a content of beta-glucans (b-G) from 1.4 to 10.7%. The enriched fraction obtained by the extraction and precipitation contained 24.7% of b-G. The differences between the ratio of stable C carbon isotopes were established. Milling fractions with coarse particles had more beta-glucans and a more negative ratio of δ13C isotope in comparison to the respective intact barley grain. However, the enriched fraction had a less negative isotope ratio. So, it is not expected that the deviation from the stable isotope ratio of grain in milling fractions is the result of the content of b-G, but it depends on other barley grain constituents. In different parts of barley grain, there are substances with different stable isotope ratios, and by milling and sieving, they are assorted to the same milling fraction with most of the b-G. The method for determining the ratio of a stable carbon isotope in diverse barley grain fractions, applied in this investigation, is potentially opening the possibility for an additional method of screening the concentration of bioactive constituents in barley grain.

Ascorbic Acid Content and Antioxidant Activities of White and Brown Teff [Eragrostic tef (Zucc.)Trotter] Grains and Injera

Teff [Eragrostis tef (Zuccagni) Trotter] is a cereal grain originating in Ethiopia as a staple food for millions of people. Its grain is a gluten-free superfood and got acceptance as a medicinal ingredient. Therefore, it is worthwhile to determine the antioxidative activities and L-ascorbic acid contents of teff grain and its baked food (injera). This study aimed to determine the ascorbic acid contents and antioxidant activities in the aqueous extract of the white and brown teff grains and their injera samples using iodimetric titration and UV-Vis spectrophotometric methods, respectively. The ascorbic acid contents in the white and brown teff ranged from 67.9–112.6 mg/100 g and 69.2–117.2 mg/100 g, respectively, and those in injera of the selected teff samples ranged from 30.5–32.9 mg/100 g and 37.3–43.0 mg/100 g, respectively. The antioxidant activities ranged from 1.26–7.04 μmol AAE/g for the white teff grains, 1.44–6.29 μmol AAE/g for the brown teff grains, 1.81–2.47 μmol AAE/g for white teff injera, and 3.89–4.86 μmol AAE/g for the brown teff injera samples. Findings of the present study have revealed that white teff and brown teff grains and their injera were found to have a higher content of ascorbic acid than commonly consumed grains and vegetables. No significant difference (α = 0.05) has been observed between the two varieties of teff grains with respect to the ascorbic acid content and antioxidant activities. However, there was a statistically significant difference (α = 0.05) in the ascorbic acid content and antioxidant activities between the teff grains and their injera samples. Therefore, this study indicated that teff grains and injera are rich in ascorbic acid content and antioxidant activities as compared to other cereal grains and are very crucial for human nutrition and health.

Identification of the genes associated with β-glucan synthesis and accumulation during grain development in barley

The presence of β-glucan in barley grains is one of its important quality traits. Lower β-glucan content is required for the barley used in beer and feed production, while higher β-glucan content is beneficial for food barley. Although intensive research has been carried out on the genotypic and environmental differences in β-glucan content in barley grains, little information is available on the molecular mechanisms underlying their genotypic differences and genetic regulation of β-glucan synthesis and accumulation. In this study, RNA sequencing analysis was conducted to compare the transcriptome profiles of two barley genotypes (BCS192 and BCS297) that greatly differ in grain β-glucan content, in order to identify the key genes responsible for β-glucan synthesis and accumulation during grain development. The results showed that carbohydrate metabolic processes and starch and sucrose metabolism play significant roles in β-glucan synthesis. The identified differently expressed genes (DEGs), which are closely associated with grain β-glucan content, are mainly involved in hydrolase activity and glucan metabolic processes. In addition, β-glucan accumulation in barley grains is predominantly regulated by photosynthesis and carbon metabolism. The DEGs identified in this study and their functions may provide new insights into the molecular mechanisms of β-glucan synthesis and genotypic differences in barley grains.

Barley in the Production of Cereal-Based Products

Barley (Hordeum vulgare L.) is unjustly neglected today as a food grain. Interest in the use of barley in the food industry has increased recently. The reason for this is its content of dietary fibre, especially β-glucan, which has been shown to reduce blood cholesterol and lower blood sugar levels. The main nutritional components of barley and barley products, besides the mentioned β-glucan, are starch, sugar, proteins, fat and ash. Although not common in the production of bakery products, barley can be very easily involved in the production of the same products, and such products have improved nutritional characteristics and acceptable sensory characteristics, which make them desirable. Barley has great potential for use in a wide range of cereal-based foods as a partial or full replacement for currently used grains (such as wheat, oats, rice and corn). This article provides basic and general information about the use of barley in food and the processing of barley grains for use in the manufacturing of cereal-based products, with particular attention to the use of barley in the manufacturing of bread (flatbread and leavened bread), noodles and pasta, muffins and cakes and cookies and biscuits.