Improving low nitrogen (LN) tolerance in barley (Hordeum vulgare L.) increases global barley yield and quality. In this study, a recombinant inbred line (RIL) population crossed between \"Baudin × CN4079\" was used to conduct field experiments on twenty traits of barley yield, agronomy, and nitrogen(N)-related traits under LN and normal nitrogen (NN) treatments for two years. This study identified seventeen QTL, comprising eight QTL expressed under both LN and NN treatments, eight LN-specific QTL, and one NN-specific QTL. The localized C2 cluster contained QTL controlling yield, agronomic, and N-related traits. Of the four novel QTL, the expression of the N-related QTL Qstna.sau-5H and Qnhi.sau-5H was unaffected by N treatment. Qtgw.sau-2H for thousand-grain weight, Qph.sau-3H for plant height, Qsl.sau-7H for spike length, and Qal.sau-7H for awn length were identified to be the four stable expression QTL. Correlation studies revealed a significant negative correlation between grain N content and harvest index (p < 0.01). These results are essential for barley marker-assisted selection (MAS) breeding.

Mitigating the negative impacts of polycyclic aromatic hydrocarbons (PAHs) is an urgent need due to their toxicity and persistence in the environment. This study investigated the use of Pseudomonas aeruginosa ASU-B6 to detoxify pyrene (PY). The bacterium P. aeruginosa ASU-B6 is capable of degrading PY by 92% as a sole carbon source after 15 days of incubation with phthalate being the major metabolic product. In this regard, the impact of pyrene (PY), P. aeruginosa ASU-B6 (ASU-B6), the bacterial strain combined with pyrene (ASU-B6/PY) and the metabolites produced after pyrene degradation (PY-metabolites) on the germination and physiological attributes of Hordeum vulgare and Vicia faba seedlings were studied. A single application of PY or ASU-B6 showed a toxic effect on the germination of both tested seeds. Interestingly, broad bean seedlings exhibited less sensitivity to PY stress in terms of growth and metabolism compared to barley. Notably, ASU-B6 inhibited fresh and dry weight of shoots and roots of barley and, to a lesser extent, reduced the germination of broad beans compared to the control. However, the combined PY-metabolites and ASU-B6/PY showed a mutual ameliorative effect on seedlings growth, alleviating the phytotoxic impact of each component. Pyrene reduced the virulence of ASU-B6 by inhibiting the production of pyocyanin pigment, while bacteria ameliorated pyrene toxicity through its degradation. Heatmap and principal component analyses highlighted that increasing the contents of hydrogen peroxide, superoxide anion, hydroxyl radical, and lipid peroxidation positively correlated to the toxicity of PY or ASU-B6. However, improving the antioxidant system which buffers the oxidative stress induced by different combinations of PY and ASU-B6 enhanced the growth of germinated seedlings corresponding to PY or ASU-B6. This study reflected the role of ASU-B6 in ameliorating PY-phytotoxicity. In addition, the application of ASU-B6 strain is recommended as a prospective candidate for remediation of PAHs-contaminated environment with a positive impact on the plant growth and metabolic products.

To decipher the molecular bases governing seed germination, this study presents the pivotal role of the cap-binding complex (CBC), comprising CBP20 and CBP80, in modulating the inhibitory effects of abscisic acid (ABA) in barley. Using both single and double barley mutants in genes encoding the CBC, we revealed that the double mutant hvcbp20.ab/hvcbp80.b displays ABA insensitivity, in stark contrast to the hypersensitivity observed in single mutants during germination. Our comprehensive transcriptome and metabolome analysis not only identified significant alterations in gene expression and splicing patterns but also underscored the regulatory nexus among CBC, ABA, and brassinosteroid (BR) signaling pathways.

Barley stripe or yellow rust (BYR) caused by Puccinia striiformis f. sp. hordei (Psh) is a significant constraint to barley production. The disease is best controlled by genetic resistance, which is considered the most economical and sustainable component of integrated disease management. In this study, we assessed the diversity of resistance to Psh in a panel of international barley genotypes (n = 266) under multiple disease environments (Ecuador, India, and Mexico) using genome-wide association studies (GWASs). Four quantitative trait loci (QTLs) (three on chromosome 1H and one on 7H) associated with resistance to Psh were identified. The QTLs were validated by mapping resistance to Psh in five biparental populations, which detected key genomic regions on chromosomes 1H (populations Pompadour/Zhoungdamei, Pompadour/Zug161, and CI9214/Baudin), 3H (Ricardo/Gus), and 7H (Fumai8/Baronesse). The QTL RpshQ.GWA.1H.1 detected by GWAS and RpshQ.Bau.1H detected using biparental mapping populations co-located were the most consistent and stable across environments and are likely the same resistance region. RpshQ.Bau.1H was saturated using population CI9214/Baudin by enriching the target region, which placed the resistance locus between 7.9 and 8.1 Mbp (flanked by markers sun_B1H_03, 0.7 cM proximal to Rpsh_1H and sun_B1H_KASP_02, 3.2 cM distal on 1HS) in the Morex reference genome v.2. A Kompetitive Allele Specific PCR (KASP) marker sun_B1H_KASP_01 that co-segregated for RpshQ.Bau.1H was developed. The marker was validated on 50 Australian barley cultivars, showing well-defined allelic discrimination and presence in six genotypes (Baudin, Fathom, Flagship, Grout, Sakurastar, and Shepherd). This marker can be used for reliable marker-assisted selection and pyramiding of resistance to Psh and in diversifying the genetic base of resistance to stripe rust.

Mixtures containing β-glucans were extracted from barley, under both mild and high alkaline conditions, to prepare biodegradable films (MA and HA, respectively), as natural dressings with intrinsic therapeutic properties. An in-depth characterization was performed to evaluate the impact of mild and high alkaline conditions on chemical, physicochemical, and biological features for potential use in wound treatments. Both MA and HA films exhibited a good ability to absorb water and simulate wound fluid, which helps maintain optimal tissue hydration. Moreover, their oxygen permeability (147.6 and 16.4 cm3 × μm/m2 × 24 h × Pa × 107, respectively) appeared adequate for the intended application. Biocompatibility tests showed that the films do not harm human dermal fibroblasts. Impressively, they promote cell attachment and growth, with MA having a stronger effect due to its higher β-glucan content. Furthermore, MA films can modulate macrophage behaviour in an inflamed microenvironment, reducing oxidative stress and pro-inflammatory cytokines, while simultaneously increasing levels of anti-inflammatory cytokines. In a scratch test, HA films allowed for faster fibroblast migration within the first 16 h compared to MA. Overall, this study demonstrates that developing β-glucan based films from barley, through a sustainable and cost-effective process, holds great promise for skin applications. These films exhibit significant potential to promote wound healing and modulate inflammation.

BACKGROUND: Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is an important disease of barley and wheat. A diverse sexual Pgt population from the Pacific Northwest (PNW) region of the US contains a high proportion of individuals with virulence on the barley stem rust resistance (R) gene, Rpg1. However, the evolutionary mechanisms of this virulence on Rpg1 are mysterious considering that Rpg1 had not been deployed in the region and the gene had remained remarkably durable in the Midwestern US and prairie provinces of Canada.
RESULTS: To identify AvrRpg1 effectors, genome wide association studies (GWAS) were performed using 113 Pgt isolates collected from the PNW (n = 89 isolates) and Midwest (n = 24 isolates) regions of the US. Disease phenotype data were generated on two barley lines Morex and the Golden Promise transgenic (H228.2c) that carry the Rpg1 gene. Genotype data was generated by whole genome sequencing (WGS) of 96 isolates (PNW = 89 isolates and Midwest = 7 isolates) and RNA sequencing (RNAseq) data from 17 Midwestern isolates. Utilizing ~1.2 million SNPs generated from WGS and phenotype data (n = 96 isolates) on the transgenic line H228.2c, 53 marker trait associations (MTAs) were identified. Utilizing ~140 K common SNPs generated from combined analysis of WGS and RNAseq data, two significant MTAs were identified using the cv Morex phenotyping data. The 55 MTAs defined two distinct avirulence loci, on supercontig 2.30 and supercontig 2.11 of the Pgt reference genome of Pgt isolate CRL 75-36-700-3. The major avirulence locus designated AvrRpg1A was identified with the GWAS using both barley lines and was delimited to a 35 kb interval on supercontig 2.30 containing four candidate genes (PGTG_10878, PGTG_10884, PGTG_10885, and PGTG_10886). The minor avirulence locus designated AvrRpg1B identified with cv Morex contained a single candidate gene (PGTG_05433). AvrRpg1A haplotype analysis provided strong evidence that a dominant avirulence gene underlies the locus.
CONCLUSIONS: The association analysis identified strong candidate AvrRpg1 genes. Further analysis to validate the AvrRpg1 genes will fill knowledge gaps in our understanding of rust effector biology and the evolution and mechanism/s of Pgt virulence on Rpg1.

In this experiment, F1s produced from a 7 × 7 half-diallel cross along with their parents were evaluated to develop high yielding and saline-tolerant barley lines. The investigation focused on the general combining ability (GCA) of parents, specific combining ability (SCA) of offspring, genetic action, and heterosis of eight quantitative variables. Genetic analysis and potence ratio suggested that different degrees of dominance controlling the inheritance of the studied traits. Significant GCA and SCA variances suggested the presence of both additive and non-additive gene actions controlling the traits. However, a GCA:SCA ratio lower than 1 indicated the preponderance of the non-additive gene action involved in the expression of the traits. The parents P5 and P6 possess the genetic potential favorable for early and short stature in their F1s. Conversely, P2 and P4 were more likely to produce short F1s with high yield potential. Based on the mean performance, SCA, and heterobeltiosis, crosses P2 × P3, P2 × P7, P3 × P4, P4 × P5, P5 × P6, and P6 × P7 were selected as promising F1s for earliness, short stature, and high yield potential. These crosses are recommended for further breeding to obtain early-maturing and high-yielding segregants. To identify saline-tolerant F1s, screening was conducted in saline media prepared in half-strength Hoagland solution. The salinity stress involved exposing F1s to 100 mM NaCl for first 10 days, and followed by an increase to 150 mM until maturity. Among the F1s, five crosses (P1 × P2, P2 × P3, P3 × P5, P4 × P6, and P4 × P7) exhibited promising signs of saline tolerance based on a comprehensive evaluation of healthy seed set, K+/Na+ ratio, root volume, generation of reactive oxygen species (O2 •- and H2O2), and activities of key antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR). These crosses will undergo further evaluation in the next filial generation to confirm heritable saline tolerance.

Genetic and agronomic advances consistently lead to an annual increase in global barley yield. Since abiotic stresses (physical environmental factors that negatively affect plant growth) reduce barley yield, it is necessary to predict barley resistance. Artificial intelligence and machine learning (ML) models are new and powerful tools for predicting product resilience. Considering the research gap in the use of molecular markers in predicting abiotic stresses, this paper introduces a new approach called GenPhenML that combines molecular markers and phenotypic traits to predict the resistance of barley genotypes to drought and salinity stresses by ML models. GenPhenML uses feature selection algorithms to determine the most important molecular markers. It then identifies the best model that predicts atmospheric resistance with lower MAE, RMSE, and higher R2. The results showed that GenPhenML with a neural network model predicted the salinity stress resistance score with MAE, RMSE and R2 values of 0.1206, 0.0308 and 0.9995, respectively. Also, the NN model predicted drought stress scores with MAE, RMSE and R2 values of 0.0727, 0.0105 and 0.9999, respectively. The GenPhenML approach was also used to classify barley genotypes as resistant and stress-sensitive. The results showed that the accuracy, accuracy and F1 score of the proposed approach for salinity and drought stress classification were higher than 97%.

Xylem sap proteomics provides crucial insights into plant defense and root-to-shoot communication. This study highlights the sensitivity and reproducibility of xylem sap proteome analyses, using a single plant per sample to track over 3000 proteins in two model crop plants, Solanum tuberosum and Hordeum vulgare. By analyzing the flg22 response, we identified immune response components not detectable through root or shoot analyses. Notably, we discovered previously unknown elements of the plant immune system, including calcium/calmodulin-dependent kinases and G-type lectin receptor kinases. Despite similarities in the metabolic pathways identified in the xylem sap of both plants, the flg22 response differed significantly: S. tuberosum exhibited 78 differentially abundant proteins, whereas H. vulgare had over 450. However, an evolutionarily conserved overlap in the flg22 response proteins was evident, particularly in the CAZymes and lipid metabolism pathways, where lipid transfer proteins and lipases showed a similar response to flg22. Additionally, many proteins without conserved signal sequences for extracellular targeting were found, such as members of the HSP70 family. Interestingly, the HSP70 response to flg22 was specific to the xylem sap proteome, suggesting a unique regulatory role in the extracellular space similar to that reported in mammalians.

The use of artificial fertilizers follows the intensification of agricultural production as a consequence of population growth, which leads to soil depletion, loss of organic matter, and pollution of the environment and production. This can be overcome by increasing the use of organic fertilizers in agriculture. In the present study, we investigated the effect of using vermicompost, biochar, mineral fertilizer, a combination of vermicompost and mineral fertilizer, and an untreated control on alluvial-meadow soil on the development of fodder winter barley Hordeum vulgare L., Zemela cultivar. We used a randomized complete block design of four replications per treatment. Barley grain yield, number of plants, and soil and microbiological parameters were studied. We found statistically proven highest grain yield and grain protein values when applying vermicompost alone, followed by the combined treatment and mineral fertilizer. The total organic carbon was increased by 70.2% in the case of vermicompost and by 44% in the case of combined treatment, both compared to the control. Thus, soil microbiome activity and enzyme activities were higher in vermicompost treatment, where the activity of β-glucosidase was 29.4% higher in respect to the control, 37.5% to the mineral fertilizer, and 24.5% to the combined treatments. In conclusion, our study found the best overall performance of vermicompost compared to the rest of the soil amendments.