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At least 19 recordsLinked to original sources
PubMed1978

Absorption and circular dichroism spectra of chloroplast membrane fragments from spinach, barley and a barley mutant at room temperature and liquid nitrogen temperature.

The absorption and CD spectra of chloroplast fragments from spinach, barley and a barley mutant (chlorophyll b-minus) were studied at temperatures of 23 degrees C and --196 degrees C. The CD spectrum of wild type barley and spinach at --196 degrees C showed troughs at 640, 653, 676 and 695 nm and a maximum at 667 nm. The CD spectrum of the barley mutant at --196 degrees C consisted of a large trough at 684 nm, a small trough at 695 nm and a positive peak at 670 nm. A new feature observed at --196 degrees C but not at 23 degrees C is the trough at 640 nm. This 640 nm CD signal is missing in the CD spectrum of the barley mutant. It is attributable to the light-harvesting chlorophyll a/b protein which appears to be missing in the mutant. Another new feature, the trough at 695 nm, was observed in the CD spectra of spinach, barley and the barley mutant at --196 degrees C. The 695 nm trough appears to be sensitive to detergents and it may be due to a labile chlorophyll a.protein complex. Possible interpretations of the data are discussed.

Chloroplasts↗
PubMed1976

Purification of malted-barley endo-beta-D-glucanases by ion-exchange chromatography: some properties of an endo-barley-beta-D-glucanase.

Two endo-beta-D-glucanases which act, respectively, on (1 leads to 3)-beta-D-glucans and barley beta-D-glucan have been isolated from malted barley, and purified by ion-exchange chromatography. The latter enzyme is highly specific for barley beta-D-glucan, and has no action on either (1 leads to 3)- or (1 leads to 4)-beta-D-glucans. It will also act on dyed barley-beta-D-glucan. Certain group-specific reagents inhibit the endo-barley-beta-D-glucanase and the endo-(1 leads to 3)-beta-D-glucanase to similar extents.

Chromatography, Ion Exchange↗
PubMed1975

The effects of processing of barley-based supplements on rumen pH, rate of digestion of voluntary intake of dried grass in sheep.

1. In one experiment the effect on rumen pH of feeding with restricted amounts of whole or pelleted barley was studied. With whole barley there was little variation in rumen pH associated with feeding time, but with pelleted barley the pH decreased from about 7-0 before feeding to about 5-3, 2--3 h after feeding. 2. The rate of disappearance of dried grass during incubation in the rumens of sheep receiving either whole or pelleted barley was studied in a second experiment. After 24 h incubation only 423 mg/g incubated had disappeared in the rumen of sheep receiving pelleted barley while 625 mg/g incubated had disappeared when it was incubated in the rumen of sheep receiving whole barley. 3. The voluntary intake of dried grass of lambs was studied in a third experiment when they received supplements of either 25 or 50 g whole or pelleted barley/kg live weight 0-75. At the high level, pelleted barley reduced intake of dried grass by 534 g/kg but whole barley reduced it by only 352 g/kg. The digestibility of acid-detergent fibre was reduced more by pelleted barley than by whole barley but there was a tendency for a small increase in digestibility of the barley due to processing. 4. The implications of these findings on supplementation of roughages with cereals are discussed.

Animal Feed↗
PubMed2025

Dissecting adult plant resistance to stem rust through multi-model GWAS in a diverse barley germplasm panel.

INTRODUCTION: Stem rust (SR), caused by Puccinia graminis f. sp. tritici (Pgt), remains a major threat to global barley production, particularly in regions with conducive environments and evolving pathogen populations. Despite progress in understanding seedling resistance, adult plant resistance (APR) to SR remains underexplored in diverse barley germplasm. This study aimed to dissect the genetic architecture of APR to SR in a panel of diverse origins of two-row spring barley using a genome-wide association study (GWAS). METHODS: A total of 273 barley accessions were evaluated for APR to SR in two distinct environments in Kazakhstan. Phenotypic data were combined with high-density SNP genotyping to perform GWAS using five statistical models (GLM, MLM, MLMM, FarmCPU, and BLINK). Population structure and kinship were accounted for to identify robust marker-trait associations (MTAs), followed by haplotype-based QTL delineation. Transcriptomic data from 16 barley tissues were used to identify candidate genes within major QTL regions. Substantial phenotypic variation in SR severity was observed across environments. RESULTS: A total of 204 MTAs were identified, among which 96 were stable across models, resulting in 19 model-stable QTLs spanning all seven barley chromosomes. Six QTLs co-localized with known SR-resistance QTLs and genes, including Rpg1 and Rpg6. Q_rpg_7H.1 (coinciding with Rpg1) was one of the strongest and most consistent QTL, harboring 42 highly expressed candidate genes. A novel major-effect QTL on chromosome 5H, Q_rpg_5H.1 (3.5 - 9.9 Mb), not previously associated with known resistance loci, contained 10 highly expressed genes grouped into three co-expression clusters, including WRKY transcription factors and PR-5 proteins. CONCLUSION: This study provides new insights into the complex, multilayered genetic control of SR resistance in barley. The discovery of both known and novel QTLs offers valuable targets for marker-assisted selection and lays the foundation for breeding durable SR-resistant barley adapted to diverse agroecological conditions.

Hordeum vulgare L.↗
PubMed2026

Genomic and evolutionary analysis reveals dynamic variations of MKK3 gene, a key regulator for seed dormancy in barley.

Barley (Hordeum vulgare L.) is an important crop in the world, and its seed dormancy is primarily controlled by a mitogen-activated protein kinase kinase 3 (MKK3) gene. Although kinase activity of MKK3 and its roles in barley post-domestication have been widely studied, the pre-domestication evolution of MKK3 and the spread of nondormant alleles among global barley varieties remain largely unexplored. In this study, we analyzed MKK3 sequences in barley and its wild progenitor (Hordeum spontaneum K. Koch) and identified two polymorphic miniature inverted-repeat transposable elements (MITEs). Comparative analyses indicated that the insertions/excision of the MITEs predated the current estimates of barley domestication. Examination of the barley pangenomes coupled with droplet digital polymerase chain reaction revealed extensive copy number variation of MKK3 and suggested that transposons likely contributed to tandem amplification of the MKK3 gene on chromosome 5H. Additionally, approximately 1-Kb MKK3 sequences were found on chromosomes 1H and 6H. Further analysis indicated that these short MKK3 sequences were captured by a CACTA transposon that also contained fragments from four other expressed genes. The acquisition of MKK3 was estimated to be between 1.9 and 2.5 million years ago. Together, these findings illuminate the dynamic pre-domestication evolution of the MKK3 gene and identify three divergent MKK3 haplotype groups including a unique lineage predominant in Ethiopian germplasm. This study highlights the contribution of transposons to structural diversification and evolutionary differentiation of the MKK3 locus and provides helpful information for understanding the complex history of MKK3 gene in barley and also for improving preharvest sprouting tolerant varieties under distinct natural conditions.

Hordeum↗
PubMed1978

Protein quality of induced high lysine mutants in barley.

Evidence of high-lysine gene sources in barley derived from spontaneous and induced mutations has been presented. In addition barley sources considered to be "normal" also differ in lysine content. Changes in lysine concentrations invariable results in changes in other amino acids in barley protein. Protein fractions are altered in several mutant barleys and differ also in so called "normal barleys". The fractions in the normal barleys are probably more dependent upon environmental conditions than in mutant barleys. It is clearly demonstrated with chemical analyses and biological experiments with rats, poultry and pigs that high-lysine cultivars are superior in nutritive quality than their low-lysine isotypes. However, it appears that most of the lysine genotypes possess reduced grain weight and lower grain yield. This is of course unfortunate as an adequate supply of food appears to be the number one nutritional priority in the world today. This does not mean, however, that protein improvement would be of no practical value under conditions of marginal energy deprivation. The literature reviewed suggests that protein improvement would likely be of value under these conditions.

Amino Acids↗
PubMed2026

Cloning, Transformation, and Reporter Gene Analysis of the SalT Promoter in Barley (Hordeum vulgare).

Constitutive gene expression can lead to pleiotropic effects. Therefore, spatial or temporal restriction of expression via specific promoters provides a more targeted approach. This study aimed to clone the SalT promoter and analyze its activity in transgenic barley using GFP and GUS reporter genes. The T-DNA constructs carrying the SalT promoter were introduced into barley cv. Golden Promise, and transgenic plants were confirmed through PCR, hygromycin selection, and Southern hybridization. Both constructs, SalT-GFP and SalT-GUS, were transformed in barley cv. Golden Promise. Here, we characterized the expression pattern of the SalT promoter in barley and utilized it to drive the expression of reporter genes GFP and GUS. The SalT promoter was isolated from rice genomic DNA, cloned into the pNos-AB-M vector, and confirmed through PCR and restriction analysis. Subsequently, GFP and GUS genes were cloned under the SalT promoter in the same vector. The constructs were then subcloned into the p6U vector for plant expression. Agrobacterium-mediated genetic transformation of barley cultivar "Golden Promise" was conducted, resulting in successful integration of the transgenes. Callus induction, regeneration, and root formation efficiency were assessed, demonstrating the potential of the SalT promoter to drive gene expression during various stages of plant development. Molecular analyses, including PCR and Southern hybridization, confirmed the presence and integration of transgenes in the barley genome. Furthermore, GFP fluorescence and GUS staining analyses revealed strong expression of the respective genes under control of the SalT promoter in different plant tissues. This study provides insights into the application of the SalT promoter for genetic manipulation and functional characterization in barley, offering opportunities for crop improvement and biotechnological applications.

Hordeum↗
PubMed1976

A barley lectin that binds free amino sugars. I. Purification and characterization.

A lectin was isolated from barley seen which bound the coat glycoprotein of barley stripe mosaic virus (Type strain) and precipitated the virus from solution. Purification of the barley lectin was achieved by fractionation with ammonium sulfate and successive column chromatography on DEAE cellulose and cellulose phosphate. The barley lectin was homogeneous as ascertained by polyacrylamide gel electrophoresis, isoelectric focusing, and from immunochemical tests. No isolectins were detected. The lectin has a molecular weight of 31 000 daltons and is not a glycoprotein. Each virion can accomodate between 200 to 300 molecules of lectin. Barley lectin was shown to be specific for D-glucosamine, D-galactosamine and D-mannosamine with little distinction among the epimeric configurations at carbons 2 and 4. Free amino groups of D-glucosamine and D-galactosamine were detected on the coat glycoprotein of Type strain barley stripe mosaic virus and these sugars appear to serve as receptors for the barley lectin.

Agglutination Tests↗
PubMed2025

Barley resistance and susceptibility to fungal cell entry involve the interplay of ROP signaling with phosphatidylinositol-monophosphates.

Rho-of-plant small GTPases (ROPs) are regulators of plant polar growth and of plant-pathogen interactions. The barley ROP, RACB, is involved in susceptibility toward infection by the barley powdery mildew fungus Blumeria hordei (Bh) but little is known about the cellular pathways that connect RACB signaling to disease susceptibility. Here we identify novel RACB interaction partners of plant or fungal origin by untargeted co-immunoprecipitation of constitutively active (CA) RACB tagged by green fluorescent protein from Bh-infected barley epidermal layers and subsequent analysis by liquid chromatography-coupled mass spectrometry. Three of the immunoprecipitated proteins, a plant phosphoinositide phosphatase, a plant phosphoinositide phospholipase, and a putative Bh-effector protein, are involved in the barley-Bh-pathosystem and support disease resistance or susceptibility, respectively. RACB and its plant interactors bind to overlapping anionic phospholipid species in vitro, and in the case of RACB, this lipid interaction is mediated by its carboxy-terminal polybasic region (PBR). Fluorescent markers for anionic phospholipids show altered subcellular distribution in barley cells during Bh attack and under expression of a RACB-binding fungal effector. Phosphatidylinositol 4-phosphate, phosphatidylinositol 3,5-bisphosphate, and phosphatidylserine show a distinct enrichment at the haustorial neck region, suggesting a connection to subcellular targeting of RACB at this site. The interplay of ROPs with anionic phospholipids and phospholipid-metabolizing enzymes may thus enable the subcellular enrichment of components pivotal for success or failure of fungal penetration.

Hordeum↗
PubMed2026

Haplotype Blocks Are Associated With Rapid Local Adaptation to Environmental Shifts in Wild Barley.

Genomic mechanisms of local adaptation must be highly responsive in geographic regions where climate is changing rapidly. The Levant region is a critical biodiversity hotspot and the distribution edge for many species, including the wild ancestor of domesticated barley. This region is under an accelerated desertification process, thus enforcing a rapid genomic response to the projected environmental changes. To elucidate the genomic basis of rapid local adaptation, we studied wild barley populations using an ecological-genetic sampling design that decouples environmental variation from demographic background. We collected and sequenced 300 wild barley individuals and evaluated the phenotypes of 3600 progeny plants over 3 years. Our genomic analyses revealed that local adaptation is associated with clusters of candidate genes forming haplotype blocks. These clusters are enriched with environment and stress responsive genes, including flowering time regulators, drought and heat responsive genes. We identified six candidate adaptive haplotype blocks which span 1-8 Mbp and are distributed across chromosomes 1H, 2H, 4H and 5H, each segregating as two major haplotypes. Additionally, we integrated over 2600 occurrence records into ecological and evolutionary modelling to assess the genomic vulnerability of populations to projected future climates. Our study identifies candidate genomic regions and environmental drivers of local adaptation in wild barley and highlights the advantage of haplotype blocks architecture in orchestrating an efficient response to rapid environmental change. We highlight the ecological factors most strongly associated with the observed evolutionary responses and provide insights and guidelines for biodiversity conservation and implementation of crop wild relatives in breeding.

Hordeum↗
PubMed2025

Integrated 16 S rRNA and transcriptome analysis reveal molecular and microbial mechanisms of cold-tolerant germination in hulless barley.

BACKGROUND: Elucidating the mechanisms underlying cold-tolerant germination is crucial for enhancing crop resilience to low temperatures. Hulless barley (Hordeum vulgare var. coeleste L.), with remarkable natural cold adaptation, serves as an ideal model to study cold stress tolerance mechanisms in gramineous crops. In this study, cold-tolerant variety 37 and cold-sensitive variety 44 were screened and used to investigate the molecular mechanisms of cold-tolerant germination, via seed germination assays, combined with phytohormone determination, transcriptome sequencing and 16 S rRNA amplicon sequencing. RESULTS: Low temperature significantly inhibited hulless barley seed germination: the germination rate of cold-sensitive variety 44 decreased by 69%, while that of cold-tolerant variety 37 only decreased by 2%. Transcriptome analysis identified 2,647 and 2,392 differentially expressed genes (DEGs) in variety 37 and 44, respectively. Weighted gene co-expression network analysis (WGCNA) revealed a green module significantly positively correlated with gibberellic acid (GA) content, containing 10 core genes such as late embryogenesis abundant protein (LEA) and Homeobox genes. 16 S rRNA sequencing showed that the cold-tolerant variety 37 had enriched abundances of dominant endophytes including Sphingomonas and Pelomonas, with correlation coefficients of 0.70 and 0.87 with GA content, respectively. Additionally, exogenous GA treatment significantly increased germination rates under cold stress by 176.67% in cold-sensitive variety 44. CONCLUSIONS: This study confirms that the enhanced cold tolerance of hulless barley during seed germination originates from the synergistic interaction between beneficial endophytes (Sphingomonas, Pelomonas), GA, and core genes (e.g., LEA, Homeobox). Exogenous GA application can significantly restore the germination ability of cold-sensitive varieties. These findings provide a critical theoretical basis for improving cold tolerance in hulless barley germplasm.

Hordeum↗
PubMed2025

On the origin of the late-flowering ppd-H1 allele in barley.

To breed for climate resilient crops, an understanding of the genetic and environmental factors influencing adaptation is critical. Barley provides a model species to study adaptation to climate change. Here we present a detailed analysis of genetic variation at a major photoperiod response locus and relate this to the domestication history and dispersal of barley. The PPD-H1 locus (a PSEUDO-RESPONSE REGULATOR 7) promotes flowering under long-day conditions, and a natural mutation at this locus resulted in a recessive, late-flowering ppd-H1 allele. This mutation proved beneficial in high-latitude environments such as Northern Europe, where it allows extended vegetative growth during long spring days. We infer the origin of the mutated late-flowering ppd-H1 allele by re-sequencing a large geo-referenced collection of 942 Hordeum spontaneum, 5 Hordeum agriocrithon and 1110 domesticated (Hordeum vulgare) barleys. We demonstrate that the late-flowering phenotype originated from Desert-type wild barley in the Southern Levant and present evidence suggesting a post-domestication origin of the mutated ppd-H1 allele.

Hordeum↗
PubMed2026

Discovering common and population-specific QTLs for leaf rust resistance in different Barley populations.

Multi-population GWAS lead to identification of common and population-specific QTLs for leaf rust resistance in barley. Genome-wide association studies (GWAS) are a powerful tool for detecting genetic markers associated with traits of interest. However, these studies are typically restricted to a single population, and transferability of identified marker effects across populations is challenged by population differences in linkage, allele frequencies, epistatic effects, and environmental context. When comparing GWAS results between populations, a lack of overlapping signals is often interpreted as a lack of common quantitative trait loci (QTLs), although such discrepancies may result from differences in statistical power to detect signals. In barley (Hordeum vulgare L.), where genetic leaf rust resistance is rapidly overcome by evolving pathogens, identification of cross-population robust and potentially transferable resistance loci is a key task. Here, we present a mixed model approach for multi-population GWAS that estimates correlated marker effects in multiple populations and use this to test for significant effects across and within populations. Applying this model to four barley breeding populations revealed both common and population-specific QTL effects for leaf rust resistance, including loci colocalizing with known Rph genes and novel regions with plausible candidate genes. Multi-population GWAS increased power, revealing signals not detected by GWAS within populations. We categorized the reported QTLs into three groups based on marker-associated allele effects: (1) consistent effect direction across populations, (2) differing effect direction across populations, and (3) present in a single population. The study highlights the transferability and limitations of leaf rust resistance QTLs across different barley populations and provides a general statistical framework to support robust marker-assisted selection across populations.

Quantitative Trait Loci↗
PubMed1979

Picosecond time-resolved fluorescence study of chlorophyll organisation and excitation energy distribution in chloroplasts from wild-type barley and a mutant lacking chlorophyll b.

Picosecond time-resolved fluorescence spectroscopy has been used to investigate the fluorescence emission from wild-type barley chloroplasts and from chloroplasts of the barley mutant, chlorina f-2, which lacks the light-harvesting chlorophyll a/b-protein complex. Cation-controlled regulation of the distribution of excitation energy was studied in isolated chloroplasts at the Fo and Fm levels. It was found that: (a) The fluorescence decay curves were distinctly non-exponential, even at low excitation intensities (less than 2 x 10(14) photons . cm(-2). (b) The fluorescence decay curves could, however, be described by a dual exponential decay law. The wild-type barley chloroplasts gave a short-lived fluorescence component of approximately 140 ps and a long-lived component of 600 ps (Fo) or 1300 ps (Fm) in the presence of Mg2+; in comparison, the mutant barley yielded a short-lived fluorescence component of approx. 50 ps and a long-lived component of 194 ps (Fo) and 424 ps (Fm). (c) The absence of the light-harvesting chlorophyll a/b-protein complex in the mutant results in a low fluorescence quantum yield which is unaffected by the cation composition of the medium. (d) The fluorescence yield changes seen in steady-state experiments on closing Photosystem II reaction centres (Fm/Fo) or on the addition of MgCl2 (+Mg2+/-Mg2+) were in overall agreement with those calculated from the time-resolved fluorescence measurements. The results suggest that the short-lived fluorescence component is partly attributable to the chlorophyll a antenna of Photosystem I, and, in part, to those light-harvesting-Photosystem II pigment combinations which are strongly coupled to the Photosystem I antenna chlorophyll. The long-lived fluorescence component can be ascribed to the light-harvesting-Photosystem II pigment combinations not coupled with the antenna of Photosystem I. In the case of the mutant, the two components appear to be the separate emissions from the Photosystem I and Photosystem II antenna chlorophylls.

Chlorophyll↗
PubMed1978

Analysis of plant genomes. III. Denaturation and reassociation properties of cryptic satellite DNAs in barley (Hordeum vulgare) and wheat (Triticum aestivum).

A cryptic satellite fraction was isolated from barley and wheat by preparatory ultracentrifugation of total DNA in Ag+-Cs2SO4 density gradients and was characterized by studying its denaturation-reassociation properties. Wheat satellite DNA underwent thermal denaturation as a single component with a Tm of 81 degrees C while barley satellite DNA consisted of one major (Tm = 82.5 degrees C) and one minor (Tm = 91 degrees C) component. When the barley and wheat satellites were reassociated and then melted, the Tm values were found to be 6--7 degrees C lower than those of the corresponding native DNA preparations. Examination of the C0t curves of these two satellite DNAs revealed the presence of a major, fast reassociating and a minor, slow reassociating fraction. The fast reassociating DNA fraction of barley was found to have a complexity of 9.7 . 10(5) daltons while that of wheat satellite was 5.8 . 10(5) daltons. Since these satellites reassociated with about 4--5% base mismatching, as judged by their deltsTm (6--7 degrees C), they each appear to consist of rather similar base sequences.

Centrifugation, Density Gradient↗