RESUMEN
The barley powdery mildew fungus, Blumeria hordei (Bh), secretes hundreds of candidate secreted effector proteins (CSEPs) to facilitate pathogen infection and colonization. One of these, CSEP0008, is directly recognized by the barley nucleotide-binding leucine-rich-repeat (NLR) receptor MLA1 and therefore is designated AVRA1. Here, we show that AVRA1 and the sequence-unrelated Bh effector BEC1016 (CSEP0491) suppress immunity in barley. We used yeast two-hybrid next-generation interaction screens (Y2H-NGIS), followed by binary Y2H and in planta protein-protein interactions studies, and identified a common barley target of AVRA1 and BEC1016, the endoplasmic reticulum (ER)-localized J-domain protein HvERdj3B. Silencing of this ER quality control (ERQC) protein increased Bh penetration. HvERdj3B is ER luminal, and we showed using split GFP that AVRA1 and BEC1016 translocate into the ER signal peptide-independently. Overexpression of the two effectors impeded trafficking of a vacuolar marker through the ER; silencing of HvERdj3B also exhibited this same cellular phenotype, coinciding with the effectors targeting this ERQC component. Together, these results suggest that the barley innate immunity, preventing Bh entry into epidermal cells, requires ERQC. Here, the J-domain protein HvERdj3B appears to be essential and can be regulated by AVRA1 and BEC1016. Plant disease resistance often occurs upon direct or indirect recognition of pathogen effectors by host NLR receptors. Previous work has shown that AVRA1 is directly recognized in the cytosol by the immune receptor MLA1. We speculate that the AVRA1 J-domain target being inside the ER, where it is inapproachable by NLRs, has forced the plant to evolve this challenging direct recognition.
Asunto(s)
Ascomicetos , Retículo Endoplásmico , Hordeum , Enfermedades de las Plantas , Inmunidad de la Planta , Proteínas de Plantas , Hordeum/microbiología , Hordeum/genética , Hordeum/inmunología , Ascomicetos/patogenicidad , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Retículo Endoplásmico/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Inmunidad de la Planta/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Dominios ProteicosRESUMEN
Crop losses caused by plant pathogens are a primary threat to stable food production. Stripe rust (Puccinia striiformis) is a fungal pathogen of cereal crops that causes significant, persistent yield loss. Stripe rust exhibits host species specificity, with lineages that have adapted to infect wheat and barley. While wheat stripe rust and barley stripe rust are commonly restricted to their corresponding hosts, the genes underlying this host specificity remain unknown. Here, we show that three resistance genes, Rps6, Rps7, and Rps8, contribute to immunity in barley to wheat stripe rust. Rps7 cosegregates with barley powdery mildew resistance at the Mla locus. Using transgenic complementation of different Mla alleles, we confirm allele-specific recognition of wheat stripe rust by Mla. Our results show that major resistance genes contribute to the host species specificity of wheat stripe rust on barley and that a shared genetic architecture underlies resistance to the adapted pathogen barley powdery mildew and non-adapted pathogen wheat stripe rust.
Asunto(s)
Hordeum/inmunología , Especificidad del Huésped , Inmunidad de la Planta , Proteínas de Plantas/inmunología , Adaptación Fisiológica , Alelos , Productos Agrícolas/genética , Grano Comestible , Fitomejoramiento , Enfermedades de las Plantas/inmunología , Puccinia , Receptores Inmunológicos , Proteínas Ribosómicas , TriticumRESUMEN
Food insecurity and malnutrition have reached critical levels with increased human population, climate fluctuations, water shortage; therefore, higher-yielding crops are in the spotlight of numerous studies. Abiotic factors affect the yield of staple food crops; among all, wheat stem sawfly (Cephus cinctus Norton) and orange wheat blossom midge (Sitodiplosis mosellana) are two of the most economically and agronomically harmful insect pests which cause yield loss in cereals, especially in wheat in North America. There is no effective strategy for suppressing this pest damage yet, and only the plants with intrinsic tolerance mechanisms such as solid stem phenotypes for WSS and antixenosis and/or antibiosis mechanisms for OWBM can limit damage. A major QTL and a causal gene for WSS resistance were previously identified in wheat, and 3 major QTLs and a causal gene for OWBM resistance. Here, we present a comparative analysis of coding and non-coding features of these loci of wheat across important cereal crops, barley, rye, oat, and rice. This research paves the way for our cloning and editing of additional WSS and OWBM tolerance gene(s), proteins, and metabolites.
Asunto(s)
Dípteros/patogenicidad , Resistencia a la Enfermedad/genética , Genoma de Planta , Himenópteros/patogenicidad , Enfermedades de las Plantas/genética , Sitios de Carácter Cuantitativo , Triticum/genética , Animales , Avena/genética , Avena/inmunología , Avena/parasitología , Mapeo Cromosómico/métodos , Dípteros/fisiología , Grano Comestible , Código Genético , Hordeum/genética , Hordeum/inmunología , Hordeum/parasitología , Humanos , Himenópteros/fisiología , Oryza/genética , Oryza/inmunología , Oryza/parasitología , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/parasitología , Carácter Cuantitativo Heredable , Secale/genética , Secale/inmunología , Secale/parasitología , Especificidad de la Especie , Triticum/inmunología , Triticum/parasitologíaRESUMEN
Plant-pathogen interactions result in disease development in a susceptible host. Plants actively resist pathogens via a complex immune system comprising both surface-localized receptors that sense the extracellular space as well as intracellular receptors recognizing pathogen effectors. To date, the majority of cloned resistance genes encode intracellular nucleotide-binding leucine-rich repeat receptor proteins. Recent discoveries have revealed tandem kinase proteins (TKPs) as another important family of intracellular proteins involved in plant immune responses. Five TKP genes-barley Rpg1 and wheat WTK1 (Yr15), WTK2 (Sr60), WTK3 (Pm24), and WTK4-protect against devastating fungal diseases. Moreover, a large diversity and numerous putative TKPs exist across the plant kingdom. This review explores our current knowledge of TKPs and serves as a basis for future studies that aim to develop and exploit a deeper understanding of innate plant immunity receptor proteins.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
Asunto(s)
Resistencia a la Enfermedad , Hordeum , Inmunidad de la Planta , Proteínas Quinasas , Triticum , Hordeum/enzimología , Hordeum/inmunología , Enfermedades de las Plantas , Proteínas Quinasas/genética , Triticum/enzimología , Triticum/inmunologíaRESUMEN
Recent research suggests that gluten-free beers by prolyl-endopeptidase treatment may not be safe for coeliac disease (CD) patients. Therefore, the gluten peptidome of an industrial gluten-free prolyl-endopeptidase treated malt beer (<10 ppm gluten) was compared to its untreated counterpart (58 ppm gluten) as a reference. NanoLC-HRMS analysis revealed the presence of 155 and 158 gluten peptides in the treated and reference beer, respectively. Characterisation of the peptides in treated beer showed that prolyl-endopeptidase activity was not complete with many peptides containing (multiple) internal proline-residues. Yet, prolyl-endopeptidase treatment did eliminate complete CD-immunogenic motifs, however, 18 peptides still contained partial, and potentially unsafe, motifs. In the reference beer respectively 7 and 37 gluten peptides carried (multiple) complete and/or partial CD-immunogenic motifs. Worrying is that many of these partial immunogenic gluten peptides do not contain a recognition epitope for the R5-antibody and would be overlooked in the current ELISA analysis for gluten quantification.
Asunto(s)
Cerveza/análisis , Glútenes/análisis , Hordeum/metabolismo , Proteómica/métodos , Secuencia de Aminoácidos , Enfermedad Celíaca/inmunología , Enfermedad Celíaca/patología , Cromatografía Líquida de Alta Presión , Glútenes/inmunología , Glútenes/metabolismo , Hordeum/inmunología , Humanos , Espectrometría de Masas , Nanotecnología , Péptidos/análisis , Péptidos/inmunología , Prolil Oligopeptidasas/metabolismoRESUMEN
Barley (Hordeum vulgare L.) Mla (Mildew resistance locus a) and its nucleotide-binding, leucine-rich-repeat receptor (NLR) orthologs protect many cereal crops from diseases caused by fungal pathogens. However, large segments of the Mla pathway and its mechanisms remain unknown. To further characterize the molecular interactions required for NLR-based immunity, we used fast-neutron mutagenesis to screen for plants compromised in MLA-mediated response to the powdery mildew fungus, Blumeria graminis f. sp. hordei. One variant, m11526, contained a novel mutation, designated rar3 (required for Mla6 resistance3), that abolishes race-specific resistance conditioned by the Mla6, Mla7, and Mla12 alleles, but does not compromise immunity mediated by Mla1, Mla9, Mla10, and Mla13. This is analogous to, but unique from, the differential requirement of Mla alleles for the co-chaperone Rar1 (required for Mla12 resistance1). We used bulked-segregant-exome capture and fine mapping to delineate the causal mutation to an in-frame Lys-Leu deletion within the SGS domain of SGT1 (Suppressor of G-two allele of Skp1, Sgt1ΔKL308-309), the structural region that interacts with MLA proteins. In nature, mutations to Sgt1 usually cause lethal phenotypes, but here we pinpoint a unique modification that delineates its requirement for some disease resistances, while unaffecting others as well as normal cell processes. Moreover, the data indicate that the requirement of SGT1 for resistance signaling by NLRs can be delimited to single sites on the protein. Further study could distinguish the regions by which pathogen effectors and host proteins interact with SGT1, facilitating precise editing of effector incompatible variants.
Asunto(s)
Eliminación de Gen , Hordeum/genética , Inmunidad de la Planta/genética , Proteínas de Plantas/genética , Ascomicetos/patogenicidad , Hordeum/inmunología , Hordeum/microbiología , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Dominios ProteicosRESUMEN
Nucleotide-binding domain leucine-rich repeat-containing receptors (NLRs) in plants can detect avirulence (AVR) effectors of pathogenic microbes. The Mildew locus a (Mla) NLR gene has been shown to confer resistance against diverse fungal pathogens in cereal crops. In barley, Mla has undergone allelic diversification in the host population and confers isolate-specific immunity against the powdery mildew-causing fungal pathogen Blumeria graminis forma specialis hordei (Bgh). We previously isolated the Bgh effectors AVRA1, AVRA7, AVRA9, AVRA13, and allelic AVRA10/AVRA22, which are recognized by matching MLA1, MLA7, MLA9, MLA13, MLA10 and MLA22, respectively. Here, we extend our knowledge of the Bgh effector repertoire by isolating the AVRA6 effector, which belongs to the family of catalytically inactive RNase-Like Proteins expressed in Haustoria (RALPHs). Using structural prediction, we also identified RNase-like folds in AVRA1, AVRA7, AVRA10/AVRA22, and AVRA13, suggesting that allelic MLA recognition specificities could detect structurally related avirulence effectors. To better understand the mechanism underlying the recognition of effectors by MLAs, we deployed chimeric MLA1 and MLA6, as well as chimeric MLA10 and MLA22 receptors in plant co-expression assays, which showed that the recognition specificity for AVRA1 and AVRA6 as well as allelic AVRA10 and AVRA22 is largely determined by the receptors' C-terminal leucine-rich repeats (LRRs). The design of avirulence effector hybrids allowed us to identify four specific AVRA10 and five specific AVRA22 aa residues that are necessary to confer MLA10- and MLA22-specific recognition, respectively. This suggests that the MLA LRR mediates isolate-specific recognition of structurally related AVRA effectors. Thus, functional diversification of multi-allelic MLA receptors may be driven by a common structural effector scaffold, which could be facilitated by proliferation of the RALPH effector family in the pathogen genome.
Asunto(s)
Ascomicetos/fisiología , Hordeum/genética , Leucina/química , Enfermedades de las Plantas/genética , Proteínas de Plantas/genética , Receptores Inmunológicos/genética , Ribonucleasas/química , Alelos , Secuencia de Aminoácidos , Regulación de la Expresión Génica de las Plantas , Variación Genética , Hordeum/inmunología , Hordeum/microbiología , Inmunidad Innata , Leucina/genética , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/metabolismo , Receptores Inmunológicos/metabolismo , Ribonucleasas/metabolismo , Homología de SecuenciaRESUMEN
KEY MESSAGE: We mapped the Rym14Hb resistance locus to barley yellow mosaic disease in a 2Mbp interval. The co-segregating markers will be instrumental for marker-assisted selection in barley breeding. Barley yellow mosaic disease is caused by Barley yellow mosaic virus and Barley mild mosaic virus and leads to severe yield losses in barley (Hordeum vulgare) in Central Europe and East-Asia. Several resistance loci are used in barley breeding. However, cases of resistance-breaking viral strains are known, raising concerns about the durability of those genes. Rym14Hb is a dominant major resistance gene on chromosome 6HS, originating from barley's secondary genepool wild relative Hordeum bulbosum. As such, the resistance mechanism may represent a case of non-host resistance, which could enhance its durability. A susceptible barley variety and a resistant H. bulbosum introgression line were crossed to produce a large F2 mapping population (n = 7500), to compensate for a ten-fold reduction in recombination rate compared to intraspecific barley crosses. After high-throughput genotyping, the Rym14Hb locus was assigned to a 2Mbp telomeric interval on chromosome 6HS. The co-segregating markers developed in this study can be used for marker-assisted introgression of this locus into barley elite germplasm with a minimum of linkage drag.
Asunto(s)
Mapeo Cromosómico/métodos , Cromosomas de las Plantas/genética , Resistencia a la Enfermedad/genética , Genes de Plantas , Hordeum/genética , Enfermedades de las Plantas/genética , Potyviridae/fisiología , Resistencia a la Enfermedad/inmunología , Marcadores Genéticos , Hordeum/inmunología , Hordeum/virología , Enfermedades de las Plantas/virologíaRESUMEN
INTRODUCTION AND OBJECTIVES: Wheat and cereal grains have a broad range of cross-reactivity, but the clinical relevance of this cross-reactivity is uncertain. This study aimed to evaluate clinical and in vitro cross-reactivity with barley, oat, and Job's tears among wheat-allergic patients. MATERIALS AND METHODS: Patients aged 5 to 15 years with IgE-mediated wheat allergy were enrolled. Skin prick test (SPT) and specific IgE (sIgE) to wheat, barley, and oat, and SPT to Job's tears were performed. Oral food challenge (OFC) was conducted if the SPT was ≤5 mm in size and there was no history of anaphylaxis to each grain. Profiles of sIgE bound allergens of wheat, barley, and oat, and inhibition ELISA of IgE binding to barley and oat with wheat were performed. RESULTS: Ten patients with a median age of 8 years were enrolled. Nine of those patients had a history of wheat anaphylaxis. The median SPT size and sIgE level to wheat was 7.3 mm and 146.5 kUA/l, respectively. The cross-reactivity rate for barley, oat, and Job's tears was 60.0%, 33.3%, and 20.0%, respectively. Significantly larger SPT size and higher sIgE level were observed in patients with positive cross-reactivity to barley and oat when compared to patients without cross-reactivity. Barley and oat extracts inhibited 59% and 16% of sIgE bound to wheat gliadins and glutenins, respectively. CONCLUSION: The cross-reactivity rate was quite low for oat and Job's tears compared to that of barley; therefore, avoidance of all cereal grains may be unnecessary in patients with severe wheat allergy
No disponible
Asunto(s)
Humanos , Masculino , Femenino , Preescolar , Niño , Adolescente , Hipersensibilidad al Trigo/inmunología , Grano Comestible/inmunología , Inmunoglobulina E/inmunología , Pruebas Cutáneas/métodos , Ensayo de Inmunoadsorción Enzimática , Hipersensibilidad a los Alimentos/diagnóstico , Hipersensibilidad a los Alimentos/inmunología , Análisis de Varianza , Factores de Tiempo , Coix/inmunología , Hordeum/inmunología , Avena/inmunología , Reacciones Cruzadas/inmunologíaRESUMEN
Wild barley accessions have evolved broad-spectrum defence against barley powdery mildew through recessive mlo mutations. However, the mlo defence response is associated with deleterious phenotypes with a cost to yield and fertility, with implications for natural fitness and agricultural productivity. This research elucidates the mechanism behind a novel mlo allele, designated mlo-11(cnv2), which has a milder phenotype compared to standard mlo-11. Bisulphite sequencing and histone ChIP-seq analyses using near-isogenic lines showed pronounced repression of the Mlo promoter in standard mlo-11 compared to mlo-11(cnv2), with repression governed by 24 nt heterochromatic small interfering RNAs. The mlo-11(cnv2) allele appears to largely reduce the physiological effects of mlo while still endorsing a high level of powdery mildew resistance. RNA sequencing showed that this is achieved through only partly restricted expression of Mlo, allowing adequate temporal induction of defence genes during infection and expression close to wild-type Mlo levels in the absence of infection. The two mlo-11 alleles showed copy number proportionate oxidase and peroxidase expression levels during infection, but lower amino acid and aromatic compound biosynthesis compared to the null allele mlo-5. Examination of highly expressed genes revealed a common WRKY W-box binding motif (consensus ACCCGGGACTAAAGG) and a transcription factor more highly expressed in mlo-11 resistance. In conclusion, mlo-11(cnv2) appears to significantly mitigate the trade-off between mlo defence and normal gene expression.
Asunto(s)
Ascomicetos/patogenicidad , Resistencia a la Enfermedad/genética , Regulación de la Expresión Génica de las Plantas/inmunología , Aptitud Genética , Hordeum/genética , Enfermedades de las Plantas/genética , Proteínas de Plantas/genética , Alelos , Ascomicetos/crecimiento & desarrollo , Variaciones en el Número de Copia de ADN , Silenciador del Gen , Hordeum/inmunología , Hordeum/microbiología , Interacciones Microbiota-Huesped/genética , Interacciones Microbiota-Huesped/inmunología , Mutación , Peroxidasa/genética , Peroxidasa/inmunología , Fenotipo , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/inmunología , Regiones Promotoras Genéticas , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Secuencias Repetidas en TándemRESUMEN
Accurately estimating cause-specific mortality for immature insect herbivores is usually difficult. The insects are exposed to abiotic and biotic mortality factors, causing cadavers to simply disappear before cause of mortality can be recorded. Also, insect herbivores are often highly mobile on hosts, making it difficult to follow patterns for individuals through time. In contrast, the wheat stem sawfly, Cephus cinctus Norton, spends its entire egg, larval, and pupal period inside a host stem. Therefore, with periodic sampling stage-specific causes of mortality can be ascertained. Consequently, we examined C. cinctus mortality in eight barley, Hordeum vulgare L., cultivars in two locations in Montana from 2016 to 2018 by collecting stem samples from stem elongation to crop maturity at weekly intervals, and collecting overwintered barley stubs the following spring and summer from the same plots. If larvae were present, we examined larval status-dead or alive-and categorized dead individuals into one of 5 mortality categories: plant defense, cannibalism, parasitism, pathogens, and unknown factors. We used multiple decrement life tables to estimate cause-specific mortality and irreplaceable mortality (the proportion of mortality from a given cause that cannot be replaced by other causes of mortality). Plant defense (antibiosis) caused 85.7 ± 3.6%, cannibalism (governed by antixenosis) caused 70.1 ± 7.6%, parasitism caused 13.8 ± 5.9%, unknown factors caused 38.5 ± 7.6%, and pathogens caused 14.7 ± 8.5% mortality in the presence of all causes of mortality. Similarly, irreplaceable mortality due to plant defense was 22.3 ± 6.4%, cannibalism was 29.1± 4.2%, unknown factors was 6.2 ± 1.8%, pathogens was 0.9 ± 0.5%, and parasitism was 1. 5 ± 0. 6%. Antibiosis traits primarily killed newly emerged larvae, while other traits supported more favorable oviposition decisions by females, increasing mortality by obligate cannibalism. Our results suggest that breeding barley for resistance to C. cinctus targeting both categories of traits (antibiosis and antixenosis) is a highly valuable tactic for management of this important pest.
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Hordeum/inmunología , Hordeum/parasitología , Himenópteros/fisiología , Tablas de Vida , Animales , Parásitos/fisiologíaRESUMEN
Rho proteins of plants (ROPs) form a specific clade of Rho GTPases, which are involved in either plant immunity or susceptibility to diseases. They are intensively studied in grass host plants, in which ROPs are signaling hubs downstream of both cell surface immune receptor kinases and intracellular nucleotide-binding leucine-rich repeat receptors, which activate major branches of plant immune signaling. Additionally, invasive fungal pathogens may co-opt the function of ROPs for manipulation of the cytoskeleton, cell invasion and host cell developmental reprogramming, which promote pathogenic colonization. Strikingly, mammalian bacterial pathogens also initiate both effector-triggered susceptibility for cell invasion and effector-triggered immunity via Rho GTPases. In this review, we summarize central concepts of Rho signaling in disease and immunity of plants and briefly compare them to important findings in the mammalian research field. We focus on Rho activation, downstream signaling and cellular reorganization under control of Rho proteins involved in disease progression and pathogen resistance.
Asunto(s)
Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas/inmunología , Enfermedades de las Plantas/genética , Inmunidad de la Planta/genética , Proteínas de Plantas/genética , Proteínas de Unión al GTP rho/genética , Animales , Arabidopsis/inmunología , Arabidopsis/microbiología , Citoesqueleto/inmunología , Citoesqueleto/microbiología , Resistencia a la Enfermedad/genética , Hordeum/genética , Hordeum/inmunología , Hordeum/microbiología , Interacciones Huésped-Patógeno/genética , Interacciones Huésped-Patógeno/inmunología , Humanos , Proteínas Repetidas Ricas en Leucina , Oryza/genética , Oryza/inmunología , Oryza/microbiología , Células Vegetales/inmunología , Células Vegetales/microbiología , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/inmunología , Proteínas/genética , Proteínas/inmunología , Transducción de Señal , Proteínas de Unión al GTP rho/inmunologíaRESUMEN
Fusarium head blight (FHB) caused by Fusarium graminearum (Fg) is a devastating disease of crops, especially wheat and barley, resulting in significant yield loss and reduced grain quality. Fg infection leads to the production of mycotoxins, whose consumption is toxic to humans and livestock. The Arabidopsis DMR6 gene encodes a putative 2-oxoglutarate Fe(II)-dependent oxygenase (2OGO) and has been identified as a susceptibility factor to downy mildew. We generated site-specific mutations in Arabidopsis At2OGO by CRISPR/Cas9 gene editing. The resulting At2OGO knock-out (KO) mutants display enhanced resistance to Fg in a detached inflorescence infection assay. Expression profiling of defense genes revealed that impairment of At2OGO function resulted in the upregulation of defense genes that are regulated by salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) pathways. Complementation of the At2OGO-KO lines with a barley (cv. Conlon) orthologue, Hv2OGO, restored susceptibility to Fg. This result indicates that the Hv2OGO gene is functionally equivalent to its Arabidopsis counterpart and, hence, may have a similar role in conditioning susceptibility to FHB in barley. These results provide a molecular basis for proposing 2OGO as a plant immunity suppressor in Arabidopsis and potentially in barley plants and establish a rationale and strategy for enhancing FHB resistance in barley.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Fusarium/fisiología , Hordeum/inmunología , Enfermedades de las Plantas/inmunología , Inmunidad de la Planta/inmunología , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Hordeum/genética , Hordeum/microbiología , Mutación , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/crecimiento & desarrolloRESUMEN
INTRODUCTION AND OBJECTIVES: Wheat and cereal grains have a broad range of cross-reactivity, but the clinical relevance of this cross-reactivity is uncertain. This study aimed to evaluate clinical and in vitro cross-reactivity with barley, oat, and Job's tears among wheat-allergic patients. MATERIALS AND METHODS: Patients aged 5 to 15 years with IgE-mediated wheat allergy were enrolled. Skin prick test (SPT) and specific IgE (sIgE) to wheat, barley, and oat, and SPT to Job's tears were performed. Oral food challenge (OFC) was conducted if the SPT was ≤5â¯mm in size and there was no history of anaphylaxis to each grain. Profiles of sIgE bound allergens of wheat, barley, and oat, and inhibition ELISA of IgE binding to barley and oat with wheat were performed. RESULTS: Ten patients with a median age of 8 years were enrolled. Nine of those patients had a history of wheat anaphylaxis. The median SPT size and sIgE level to wheat was 7.3â¯mm and 146.5 kUA/l, respectively. The cross-reactivity rate for barley, oat, and Job's tears was 60.0%, 33.3%, and 20.0%, respectively. Significantly larger SPT size and higher sIgE level were observed in patients with positive cross-reactivity to barley and oat when compared to patients without cross-reactivity. Barley and oat extracts inhibited 59% and 16% of sIgE bound to wheat gliadins and glutenins, respectively. CONCLUSION: The cross-reactivity rate was quite low for oat and Job's tears compared to that of barley; therefore, avoidance of all cereal grains may be unnecessary in patients with severe wheat allergy.
Asunto(s)
Alérgenos/inmunología , Grano Comestible/efectos adversos , Hipersensibilidad al Trigo/inmunología , Adolescente , Alérgenos/administración & dosificación , Avena/efectos adversos , Avena/inmunología , Niño , Preescolar , Coix/efectos adversos , Coix/inmunología , Reacciones Cruzadas , Grano Comestible/inmunología , Femenino , Hordeum/efectos adversos , Hordeum/inmunología , Humanos , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Masculino , Índice de Severidad de la Enfermedad , Pruebas Cutáneas/estadística & datos numéricos , Tailandia , Triticum/efectos adversos , Triticum/inmunología , Hipersensibilidad al Trigo/sangre , Hipersensibilidad al Trigo/diagnóstico , Hipersensibilidad al Trigo/dietoterapiaRESUMEN
In this study, we demonstrated the feasibility of isolating recombinant phage-antibodies against gluten from a non-immunized library of human single-domain antibodies (dAbs). Phage display technology enabled the selection of affinity probes by successive rounds of biopanning against a biotinylated synthetic peptide comprising repetitive immunogenic gluten motifs. The analysis of a wide representation of heterologous plant species corroborated that two of the isolated clones were specific to wheat, barley and rye proteins. The phage antibody selected as the most appropriate clone for the detection of gluten in foods (dAb8E-phage) was further applied in an indirect ELISA to the analysis of 50 commercial food samples. Although the limit of detection achieved did not improve those of current immunoassays, the proposed methodology could provide promising new pathways for the generation of recombinant antibodies that allow a comprehensive determination of gluten in foods, whilst replacing the need for animal immunization.
Asunto(s)
Alérgenos/inmunología , Análisis de los Alimentos , Glútenes/inmunología , Hordeum/inmunología , Proteínas de Plantas/inmunología , Secale/inmunología , Triticum/inmunología , Ensayo de Inmunoadsorción Enzimática , Alimentos , Glútenes/análisis , Hordeum/química , Humanos , Fragmentos de Inmunoglobulinas/inmunología , Biblioteca de Péptidos , Proteínas de Plantas/química , Secale/química , Triticum/químicaRESUMEN
Bymovirus-induced yellow mosaic diseases seriously threaten global production of autumn-sown barley and wheat, which are two of the presently most important crops around the world. Under natural field conditions, the diseases are caused by infection of soil-borne plasmodiophorid Polymyxa graminis-transmitted bymoviruses of the genus Bymovirus of the family Potyviridae. Focusing on barley and wheat, this article summarizes the achievements on taxonomy, geography and host specificity of these disease-conferring viruses, as well as the genetics of resistance in barley, wheat and wild relatives. Moreover, based on recent progress of barley and wheat genomics, germplasm resources and large-scale sequencing, the exploration and isolation of corresponding resistant genes from wheat and barley as well as relatives, no matter what a large and complicated genome is present, are becoming feasible and are discussed. Furthermore, the foreseen advances on cloning of the resistance or susceptibility-encoding genes, which will provide the possibility to explore the functional interaction between host plants and soil-borne viral pathogens, are discussed as well as the benefits for marker-assisted resistance breeding in barley and wheat.
Asunto(s)
Resistencia a la Enfermedad/inmunología , Regulación de la Expresión Génica de las Plantas , Hordeum/inmunología , Enfermedades de las Plantas/inmunología , Proteínas de Plantas/metabolismo , Potyviridae/aislamiento & purificación , Triticum/inmunología , Resistencia a la Enfermedad/genética , Genoma Viral , Hordeum/genética , Hordeum/virología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/virología , Proteínas de Plantas/genética , Triticum/genética , Triticum/virologíaRESUMEN
Plants survey their environment for the presence of potentially harmful or beneficial microbes. During colonization, cell surface receptors perceive microbe-derived or modified-self ligands and initiate appropriate responses. The recognition of fungal chitin oligomers and the subsequent activation of plant immunity are well described. In contrast, the mechanisms underlying ß-glucan recognition and signaling activation remain largely unexplored. Here, we systematically tested immune responses towards different ß-glucan structures and show that responses vary between plant species. While leaves of the monocots Hordeum vulgare and Brachypodium distachyon can recognize longer (laminarin) and shorter (laminarihexaose) ß-1,3-glucans with responses of varying intensity, duration and timing, leaves of the dicot Nicotiana benthamiana activate immunity in response to long ß-1,3-glucans, whereas Arabidopsis thaliana and Capsella rubella perceive short ß-1,3-glucans. Hydrolysis of the ß-1,6 side-branches of laminarin demonstrated that not the glycosidic decoration but rather the degree of polymerization plays a pivotal role in the recognition of long-chain ß-glucans. Moreover, in contrast to the recognition of short ß-1,3-glucans in A. thaliana, perception of long ß-1,3-glucans in N. benthamiana and rice is independent of CERK1, indicating that ß-glucan recognition may be mediated by multiple ß-glucan receptor systems.
Asunto(s)
Inmunidad de la Planta , beta-Glucanos/metabolismo , Arabidopsis/inmunología , Arabidopsis/metabolismo , Brachypodium/inmunología , Brachypodium/metabolismo , Capsella/inmunología , Capsella/metabolismo , Glucanos/metabolismo , Hordeum/inmunología , Hordeum/metabolismo , Oligosacáridos/metabolismo , Hojas de la Planta/inmunología , Hojas de la Planta/metabolismo , Proteínas de Plantas/metabolismo , Receptores Inmunológicos/metabolismo , Especificidad de la Especie , Nicotiana/inmunología , Nicotiana/metabolismoRESUMEN
Celiac disease (CeD) is driven by CD4+ T-cell responses to dietary gluten proteins of wheat, barley, and rye when deamidated gluten epitopes are presented by certain disease-associated HLA-DQ allotypes. About 90% of the CeD patients express HLA-DQ2.5. In such patients, five gluten epitopes dominate the anti-gluten T-cell response; two epitopes unique to wheat, two epitopes present in wheat, barley, and rye and one epitope unique to barley. Despite presence of barley in commonly consumed food and beverages and hence being a prominent source of gluten, knowledge about T-cell responses elicited by barley in CeD is scarce. Therefore, in this study, we explored T-cell response toward the barley unique epitope DQ2.5-hor-3 (PIPEQPQPY) by undertaking HLA-DQ:gluten peptide tetramer staining, single-cell T-cell receptor (TCR) αß sequencing, T-cell cloning, and T-cell proliferation studies. We demonstrate that majority of the CeD patients generate T-cell response to DQ2.5-hor-3, and this response is characterized by clonal expansion, preferential TCR V-gene usage and public TCR features thus echoing findings previously made for wheat gluten epitopes. The knowledge that biased and public TCRs underpin the T-cell response to all the immunodominant gluten epitopes in CeD suggests that such T cells are promising diagnostic and therapeutic targets.
Asunto(s)
Enfermedad Celíaca/inmunología , Hipersensibilidad a los Alimentos/inmunología , Glútenes/inmunología , Hordeum/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Linfocitos T CD4-Positivos/inmunología , Epítopos de Linfocito T/inmunología , Femenino , Antígenos HLA-DQ/inmunología , Humanos , Epítopos Inmunodominantes/inmunología , Activación de Linfocitos/inmunología , MasculinoRESUMEN
Puccinia striiformis f. sp. hordei, the causal organism of stripe rust in barley poses serious threats to its production. The present study examined the seedling response and changes in antioxidant defence system along with NADPH oxidase, hydrogen peroxide, and lipid peroxidation marker-malondialdehyde (MDA) in the four barley genotypes namely Jyoti, RD2900, RD2901, and RD2552 in response to M and G-races of stripe rust pathogen. Disease reaction showed Jyoti as susceptible genotype, RD2901 and RD2552 as resistant, whereas RD2900 behaved differentially to both the races. M-race which is predominant was found to be more virulent than G-race of barley stripe rust pathogen. RD2901 showed an increase in activities of NADPH oxidase, catalase, peroxidase, and enzymes of ascorbate-glutathione pathway along with ascorbate and glutathione pool on inoculation with M-race, which was accompanied by the decrease in hydrogen peroxide and MDA contents. Jyoti, on the other hand, showed an increase in peroxidase and glutathione-S-transferase activities only which were unable to maintain redox homeostasis. The scrutiny of data indicated an increase in ASA/DHA ratio on infection in all the genotypes irrespective of their behaviour towards the races. However, GSH/GSSG ratio significantly declined in Jyoti and increased or remained unaffected in the resistant genotypes which suggested that GSH/GSSG might be playing a vital role in imparting tolerance against stripe rust. Further, correlation studies also revealed that leaf damage was positively correlated with H2O2 and MDA contents.