Resistant Barley Research Articles

Resistance of barley varieties to Heterodera avenae in the Qinghai–Tibet Plateau, China

The cereal cyst nematode, Heterodera avenae, is one of the most economically important pathogens impacting the worldwide production of cereals and is widely distributed in more than 16 regions in China. The present study used the numbers of nematodes inside the plant roots to evaluate the resistance/susceptibility of different subpopulations of barley Hordeum vulgare (QH2R, QH6R and TB2R) to H. avenae under field and pot conditions. Nematode development in two highly resistant varieties was also evaluated by in vivo experiment and microscopic observation. Analyses of 186 selected varieties showed the numbers of susceptible varieties identified with the number of females/cysts per plant (NFP) method were significantly higher than those identified with the Pf/Pi ratio (PPR) method, which indicated that the NFP method rather than the PPR method is more reliable to evaluate the resistance of barley. The field and pot experiment results indicated that the QH2R subpopulation had lower females/cysts numbers than QH6R and TB2R subpopulations, and eight HR varieties (Sunong 7617, Sunong 7635, Dongyuan 87-14, Rudong 14-46, Rudong 87-57, Rudong 87-8-45, Rudong 88-14-2, and Rudong 88-67-1) were identified in QH2R, with the NFP numbers below 4.2. Further microscopic observation of nematode development suggested that H. avenae often penetrated less into highly resistant varieties (Sunong 7635 and Dongyuan 87-14) and more frequently failed to develop into females than the susceptible barleys. The promising resistant varieties identified in the present research might be helpful for breeders to develop CCN-resistant cultivars and control H. avenae populations effectively at low costs.

Near-Isogenic Barley Lines Show Enhanced Susceptibility to Powdery Mildew Infection Following High-Temperature Stress.

Barley cultivation is adversely affected by high-temperature stress, which may modulate plant defense responses to pathogens such as barley powdery mildew (Blumeria graminis f. sp. hordei, Bgh). Earlier research focused mainly on the influence of short-term heat stress (heat shock) of barley on Bgh infection. In this study, our aim was to investigate the effects of both short- and long-term heat stress (35 °C from 30 s to 5 days) on Bgh infection in the barley cultivar Ingrid and its near-isogenic lines containing different powdery mildew resistance genes (Mla12, Mlg, and mlo5) by analyzing symptom severity and Bgh biomass with RT-qPCR. The expression of selected barley defense genes (BAX inhibitor-1, Pathogenesis- related protein-1b, Respiratory burst oxidase homologue F2, and Heat shock protein 90-1) was also monitored in plants previously exposed to heat stress followed by inoculation with Bgh. We demonstrated that pre-exposure to short- and long-term heat stress negatively affects the resistance of all resistant lines manifested by the appearance of powdery mildew symptoms and increased Bgh biomass. Furthermore, prolonged heat stress (48 and 120 h) enhanced both Bgh symptoms and biomass in susceptible wild-type Ingrid. Heat stress suppressed and delayed early defense gene activation in resistant lines, which is a possible reason why resistant barley became partially susceptible to Bgh.

Validation of Molecular Markers of Barley Net Blotch Resistance Loci on Chromosome 3H for Marker-Assisted Selection

The most widespread and harmful disease of barley is net form of net blotch caused by the ascomycete Pyrenophora teres f. teres Drechsler (Ptt). A cost effective and environmentally sustainable strategy for barley protection against Ptt is to develop barley cultivars possessing genetic resistance. In previous GWA analysis, we identified SNP-markers associated with a resistance locus on chromosome 3H in the interval of 45.82–54.53 cM. These SNPs have been described previously in the literature to be located within the same region of chromosome 3H. The aim of the study was to validate QTL markers controlling resistance to Ptt on chromosome 3H in this region by KASP genotyping in four F2 populations of crosses between the resistant cultivars, Morex, Fox, and Zolo, and the accession, Local k-21578, with the susceptible barley cv. Gesine and in a doubled haploid (DH) population of Canadian Lake Shore (CLS)/Harrington. Eleven of fifteen studied markers showed high efficacy (97.5–100%) for co-segregation with resistance to Ptt in the DH population, CLS/Harrington. Three of these markers located at 54.53 cM and one at 51.27 cM were effective in two F2 populations of crosses of Morex and Fox with susceptible cv. Gesine. These markers are also located close to each other on the physical map (442,203,921–443,119,491 bp). Apparently, in cultivars, CLS, Morex, and Fox, resistance to Ptt is determined by the same locus. Markers JHI-Hv50k-2016-166392 (47.1 cM, 112,536,071 bp), Clone ID 3255462_1 (51.63 cM, 363,531,898 bp), and Clone ID 3255462_2 (51.63 cM, 363,531,871 bp) showed high efficacy in the DH population and in the F2 population, Local k-21578/Gesine. Apparently, at least two loci controlling Ptt resistance exist in the chromosome region of 47.0–54.3 cM: one at 46.0–48.44 cM and another at 51.27–54.8 cM. These regions were found to harbor several genes involved in important plant functions, including disease response and signaling pathways. Allele-specific PCR markers were developed based on the KASP assay data and tested on six resistant, two moderately resistant, and two susceptible barley genotypes. Four markers were found to be effective to differentiate susceptible and resistant barley genotypes. The KASP and allele-specific PCR markers associated with Ptt resistance on chromosome 3H will be useful for pyramiding resistance QTLs in barley marker-assisted selection.

Selection value of samples spring barley for dry resistance in the conditions of the Eastern Part of the Forest Steppe of Ukraine

The results of three annual studies on the studied reaction of spring barley plants to the level of moisture supply during the growing season have already been covered. In order to study the diversity of collection samples of spring barley in response to drought, we used an index approach, which is widely used by foreign scientists. With the help of the seven most common of them. These are: drought susceptibility index, tolerance index, average yield, yield stability index, yield index, stress tolerance index and geometric mean yield. 37 samples of spring barley from the collection have already been evaluated to establish the selection value of these samples for drought resistance. According to the results of the evaluation of the collection of spring barley cuttings according to dry resistance indices, it has already been established that the samples: Vodohrai (UKR), Nutans 108 (RUS); Nutans 553 (RUS), Nutans 642 (RUS), Omskyi 90 (RUS), Orenburhskyi 35 (RUS), Karabalykskyi 43 (KAZ); Nutans 89 (KGZ) had a higher level of dry resistance compared to other samples from the collection. These samples can be involved in breeding programs to create competitive varieties of spring barley, which will be adapted to the conditions of the eastern part of the ForestSteppe of Ukraine. Keywords: spring barley, selection, dry resistance, indices of dry resistance, tolerance, stress, adaptation.

Host Genotype and Weather Effects on Fusarium Head Blight Severity and Mycotoxin Load in Spring Barley.

Epidemiology of Fusarium Head Blight (FHB) of spring barley is relatively little understood. In a five-year study, we assessed quantitative resistance to FHB in an assortment of 17 spring barley genotypes in the field in southern Germany. To this end, we used soil and spray inoculation of plants with F. culmorum and F. avenaceum. This increased disease pressure and provoked genotypic differentiation. To normalize effects of variable weather conditions across consecutive seasons, we used a disease ranking of the genotypes based on quantification of fungal DNA contents and multiple Fusarium toxins in harvested grain. Together, this allowed for assessment of stable quantitative FHB resistance of barley in several genotypes. Fungal DNA contents were positively associated with species-specific Fusarium toxins in single years and over several years in plots with soil inoculation. In those plots, plant height limited FHB; however, this was not observed after spray inoculation. A multiple linear regression model of recorded weather parameter and fungal DNA contents over five years identified time periods during the reproductive phase of barley, in which weather strongly influenced fungal colonization measured in mature barley grain. Environmental conditions before heading and late after anthesis showed strongest associations with F. culmorum DNA in all genotypes, whereas for F. avenaceum, this was less consistent where we observed weather-dependent associations, depending on the genotype. Based on this study, we discuss aspects of practical resistance breeding in barley relevant to improve quantitative resistance to FHB and associated mycotoxin contaminations.

Possible influence of abiotic factors on the resistance of barley and oats to rust diseases

Possible influence of abiotic factors on the resistance of barley and oats to rust diseases

Mixed Organic and Inorganic Amendments Enhance Soil Microbial Interactions and Environmental Stress Resistance of Tibetan Barley on Plateau Farmland

Mixed Organic and Inorganic Amendments Enhance Soil Microbial Interactions and Environmental Stress Resistance of Tibetan Barley on Plateau Farmland

Mixed Organic and Inorganic Amendments Enhance Soil Microbial Interactions and Environmental Stress Resistance of Tibetan Barley on Plateau Farmland

Mixed Organic and Inorganic Amendments Enhance Soil Microbial Interactions and Environmental Stress Resistance of Tibetan Barley on Plateau Farmland

International Conference on Recent updates in Disease Treatments - EYAN 2021

This special issue is highly related to Microscopic examinations of the tissue of the medulla from the corticalsubcortical region on the injured side after a traumatic brain injury and various exercises were performed. Also it focuses on to identify possible ways to protect the rights of people who have lost their jobs due to the spread of COVID-19, analyse the effectiveness of international experience and propose promising changes to labour legislation in this area. In addition, grotechnical Methods of Increasing Drought Resistance of Spring Barley, The Role of Il4 in Contraction of Tracheal Muscle Among Rats, Stabilization of Mast Cell Membranes by Sodium Cromoglicate in Smooth Muscle Contraction of Trachea and Bronchi of The Rat, are been focused in this issues. This special issue focuses on those spects with much implication for the health care. The articles published in this special issue will certainly bring as positive effect for the developing health care and to make use of available resources and to remove certain obsolete factors and process which may delay or harm the existing health care system. It enhances maximum utilization of scientific knowledge to potentiate therapy and diagnosis in the health care system. With the above discussion in mind, the papers are broadly divided into those describing applications of biotechnology and nanotechnology in biological sense. This Special Issue presents range of applications for biotechnology and nanobiotechnology for human health and environment. It is hoped that the reader will gain, from a reading of these papers a better appreciation and recent advances in the area.

Genome-Wide Association Study for Powdery Mildew and Rusts Adult Plant Resistance in European Spring Barley from Polish Gene Bank

Rusts and powdery mildew are diseases that have a major effect on yield loss in barley. Adult Plant Resistance (APR) is a post-seedling resistance mechanism and its expression is influenced by many factors, including host susceptibility and weather conditions, as well as the timing and severity of disease outbreaks. There are two mechanisms associated with APR: non-hypersensitive and minor gene APR. In this study, 431 European barley accessions were evaluated phenotypically over 2 years (2018–2019) under field conditions, scoring APR to powdery mildew (PM), barley brown rust (BBR), and stem rust (SR), and genotypically using DArTseq. Accessions were grouped into sub-collections by cultivation period (group A—cultivated prior 1985, B—cultivated after 1985, and C—Polish landraces) and by European country of origin or European region. GWAS was conducted for PM, BBR, and SR, and scored at the heading (HA) and milky-waxy (MW) seed stages in 2019 and maximum scores across all replicates were obtained 2018–2019. Disease severity was sufficient to differentiate the collection according to cultivation time and country of origin and to determine SNPs. Overall, the GWAS analysis identified 73 marker–trait associations (MTAs) with these traits. For PM resistance, we identified five MTAs at both the HA stage and when considering the maximal disease score across both growth stages and both years. One marker (3432490-28-T/C) was shared between these two traits; it is located on chromosome 4H. For BBR resistance, six MTAs at HA and one MTA at the MW stage in 2019 and seven MTAs, when considering the maximal disease score across both growth stages and both years, were identified. Of the 48 markers identified as being associated with SR resistance, 12 were on chromosome 7H, 1 was in the telomeric region of the short arm, and 7 were in the telomeric region of the long arm. Rpg1 has previously been mapped to 7HS. The results of this study will be used to create a Polish Gene Bank platform for precise breeding programs. The resistant genotypes and MTA markers will serve as a valuable resource for breeding for PM, BBR, and SR resistance in barley.

Evaluation of Barley (Hordeum vulgare) and Wheat (Triticum aestivum) for Resistance to Hessian Fly, Mayetiola destructor, in a Controlled Environment

Small grains are widely grown as a cool-season forage crop for beef cattle and dairy industries in Texas. Small grains such as wheat (Triticum aestivum L.) for grazing are typically planted early in the fall and hence are more vulnerable to infestation by Hessian fly, Mayetiola destructor (Say). Although delaying planting until cooler weather can reduce pressure, Texas does not have a “fly free” date like many northern states. However, other small grains such as barley (Hordeum vulgare L.) might be less prone to damage by Hessian fly. An experiment in a controlled environment was used to determine resistance of winter barley, hard red winter wheat, and hard red spring wheat lines to Hessian fly and compare infestations among species. Infested tillers of winter wheat were collected and put with barley and wheat lines at Feekes growth stage 1.1 in a growth chamber. Approximately 2 weeks later, plants were dissected and numbers of Hessian fly larvae and pupae were counted. Hessian fly infestations significantly greater than zero using Fisher's LSD (P < 0.1) were considered susceptible while those not significantly different were resistant. Results showed that 42 of 136 (30.9%) winter barley, 31 of 40 (77.5%) winter wheat, and eight of 24 (33.3%) spring wheat genotypes were susceptible to the biotype of Hessian fly. The average numbers of Hessian flies per tiller were 2.2, 4.8, and 7.6 for barley, spring wheat, and winter wheat lines, respectively. Barley was a less preferred host than wheat and might be better suited in areas with abundant Hessian flies.

Identification of novel QTL contributing to barley yellow mosaic resistance in wild barley (Hordeum vulgare spp. spontaneum)

BackgroundBarley yellow mosaic disease (BYMD) caused by Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV) seriously threatens the production of winter barley. Cultivating and promoting varieties that carry disease-resistant genes is one of the most powerful ways to minimize the disease’s effect on yield. However, as the BYMD virus mutates rapidly, resistance conferred by the two cloned R genes to the virus had been overcome by new virus strains. There is an urgent need for novel resistance genes in barley that convey sustainable resistance to newly emerging virus strains causing BYMD.ResultsA doubled haploid (DH) population derived from a cross of SRY01 (BYMD resistant wild barley) and Gairdner (BYMD susceptible barley cultivar) was used to explore for QTL of resistance to BYMD in barley. A total of six quantitative trait loci (qRYM-1H, qRYM-2Ha, qRYM-2Hb, qRYM-3H, qRYM-5H, and qRYM-7H) related to BYMD resistance were detected, which were located on chromosomes 1H, 2H, 3H, 5H, and 7H. Both qRYM-1H and qRYM-2Ha were detected in all environments. qRYM-1H was found to be overlapped with rym7, a known R gene to the disease, whereas qRYM-2Ha is a novel QTL on chromosome 2H originated from SRY01, explaining phenotypic variation from 9.8 to 17.8%. The closely linked InDel markers for qRYM-2Ha were developed which could be used for marker-assisted selection in barley breeding. qRYM-2Hb and qRYM-3H were stable QTL for specific resistance to Yancheng and Yangzhou virus strains, respectively. qRYM-5H and qRYM-7H identified in Yangzhou were originated from Gairdner.ConclusionsOur work is focusing on a virus disease (barley yellow mosaic) of barley. It is the first report on BYMD-resistant QTL from wild barley accessions. One novel major QTL (qRYM-2Ha) for the resistance was detected. The consistently detected new genes will potentially serve as novel sources for achieving pre-breeding barley materials with resistance to BYMD.

Identification of Block-Structured Covariance Matrix on an Example of Metabolomic Data

Modern investigation techniques (e.g., metabolomic, proteomic, lipidomic, genomic, transcriptomic, phenotypic), allow to collect high-dimensional data, where the number of observations is smaller than the number of features. In such cases, for statistical analyzing, standard methods cannot be applied or lead to ill-conditioned estimators of the covariance matrix. To analyze the data, we need an estimator of the covariance matrix with good properties (e.g., positive definiteness), and therefore covariance matrix identification is crucial. The paper presents an approach to determine the block-structured estimator of the covariance matrix based on an example of metabolomic data on the drought resistance of barley. This method can be used in many fields of science, e.g., in agriculture, medicine, food and nutritional sciences, toxicology, functional genomics and nutrigenomics.

Mining Middle Eastern and Central Asian Barley Germplasm to Understand Diversity for Resistance to Puccinia hordei, Causal Agent of Leaf Rust

Vast collections of barley germplasm have been established and conserved in various global gene banks. These collections hold tremendous genetic diversity for resistance genes to Puccinia hordei, a causal agent of barley leaf rust. This study was undertaken to discover, characterize and postulate the known Rph genes (resistance to Puccinia hordei) and identify novel sources of ASR (all-stage resistance) and APR (adult plant resistance) to P. hordei. A core set of 315 barley lines were rust-tested as seedlings for their response to eight Australian pathotypes of P. hordei and genotyped with molecular markers linked to the known characterised ASR and APR genes. These tests led to the postulation of ASR leaf rust resistance genes Rph1, Rph2, Rph3, Rph9.am, Rph12, Rph15, Rph19 and Rph25 singly or in combination. Field tests revealed that the vast majority of lines (84%) carried APR. Genotyping of the APR-carrying lines with markers bPb-0837, Ebmac0603 and sun43-44 identified lines that likely carry the known APR genes Rph20, Rph23 and Rph24 singly or in combination. Thirty-nine per cent of the lines were negative for all the three markers and were thus postulated to carry uncharacterized APR. The sources of resistance identified in this study provide a valuable resource to breeders for further utilization and diversifying the genetic basis of leaf rust resistance in barley.

Identification of a bio-signature for barley resistance against Pyrenophora teres infection based on physiological, molecular and sensor-based phenotyping

Necrotic and chlorotic symptoms induced during Pyrenophora teres infection in barley leaves indicate a compatible interaction that allows the hemi-biotrophic fungus Pyrenophora teres to colonise the host. However, it is unexplored how this fungus affects the physiological responses of resistant and susceptible cultivars during infection. To assess the degree of resistance in four different cultivars, we quantified visible symptoms and fungal DNA and performed expression analyses of genes involved in plant defence and ROS scavenging. To obtain insight into the interaction between fungus and host, we determined the activity of 19 key enzymes of carbohydrate and antioxidant metabolism. The pathogen impact was also phenotyped non-invasively by sensor-based multireflectance and –fluorescence imaging.Symptoms, regulation of stress-related genes and pathogen DNA content distinguished the cultivar Guld as being resistant. Severity of net blotch symptoms was also strongly correlated with the dynamics of enzyme activities already within the first day of infection. In contrast to the resistant cultivar, the three susceptible cultivars showed a higher reflectance over seven spectral bands and higher fluorescence intensities at specific excitation wavelengths. The combination of semi high-throughput physiological and molecular analyses with non-invasive phenotyping enabled the identification of bio-signatures that discriminates the resistant from susceptible cultivars.

Genome-Wide Identification of the HMA Gene Family and Expression Analysis under Cd Stress in Barley.

In recent years, cadmium (Cd) pollution in soil has increased with increasing industrial activities, which has restricted crop growth and agricultural development. The heavy metal ATPase (HMA) gene family contributes to heavy metal stress resistance in plants. In this study, 21 HMA genes (HvHMAs) were identified in barley (Hordeum vulgare L., Hv) using bioinformatics methods. Based on phylogenetic analysis and domain distribution, barley HMA genes were divided into five groups (A–E), and complete analyses were performed in terms of physicochemical properties, structural characteristics, conserved domains, and chromosome localization. The expression pattern analysis showed that most HvHMA genes were expressed in barley and exhibited tissue specificity. According to the fragments per kilobase of exon per million fragments values in shoots from seedlings at the 10 cm shoot stage (LEA) and phylogenetic analysis, five HvHMA genes were selected for expression analysis under Cd stress. Among the five HvHMA genes, three (HvHMA1, HvHMA3, and HvHMA4) were upregulated and two (HvHMA2 and HvHMA6) were downregulated following Cd treatments. This study serves as a foundation for clarifying the functions of HvHMA proteins in the heavy metal stress resistance of barley.

Powdery mildew resistance of barley accessions from Dagestan.

Powdery mildew caused by the parasitic fungus Blumeria graminis (DC.) Golovin ex Speer f. sp. hordei Marchal is one of the most common diseases of barley. Growing resistant varieties can signif icantly minimize harmful effects of the pathogen. The specif icity in the interaction between the fungus and its host plant requires a continuous search for new donors of the resistance trait. The powdery mildew resistance of 264 barley accessions from Dagestan and genetic control of the trait in resistant forms were studied under f ield and laboratory conditions. Forty-seven barley lines carrying previously identif ied powdery mildew resistance genes were also examined. During three years, the experimental material was evaluated under severe infection pressure at the Dagestan Experiment Station of VIR (North Caucasus, Derbent). Juvenile resistance against the Northwest (St. Petersburg, Pushkin) pathogen population was evaluated in a climatic chamber. The genetic control of B. graminis resistance in the selected accessions was studied with the application of hybridological and molecular analyses. The level of genetic diversity of Dagestan barley for effective resistance to powdery mildew is very low. Only two accessions, VIR-23787 and VIR-28212, are resistant against B. graminis at both seedling and adult plant stages. The high-level resistance of breeding line VIR-28212 originating from barley landrace VIR-17554 (Ep-80 Abyssinien) from Ethiopia is controlled by the recessive gene mlo11. Accession VIR-17554 is heterogeneous for the studied trait, with the powdery mildew resistant genotypes belonging to two varieties, dupliatrum (an awnless phenotype) and nigrinudum (an awned phenotype). In accession VIR-23787, a recessive resistance gene distinct from the mlo11 allele was identif ied. This accession is supposed to be protected by a new, effective pathogen resistance gene.

Plant Extracts Inducing Enzyme Activity in Grains Against Loose Smut Disease

Abstract This study investigated the role of endogenous Palestinian plant extracts in inducing wheat and barley resistance systems against loose smut disease with the aim to alternate the chemical pest control with natural fungicides. Twenty indigenous herbal plant extracts and essential oils were assessed for their biological and antifungal properties against Ustilago tritici and Ustilago nuda. Their potential role in inducing resistance pathways was studied on four different cultivars of wheat and barley. Two common enzyme indicators – guaiacol peroxidase (POX) and polyphenol oxidase (PPO) – are expressed in plants only after physical or chemical induction. The antifungal activity of the plant extracts was investigated in vitro. Totally 70 % of the plant extracts showed antifungal activity against Ustilago tritici and Ustilago nuda. Coridothyme extracts ranked first (61 %) in the fungal growth inhibition, followed by varthemia, salvia, ambrosia, artemisia, and lemon thyme. Some plant extracts significantly increased the POX and PPO effect compared to control for all the wheat and barley cultivars tested. The study revealed that oregano, clove or lavender and pomegranate, common yarrow or chamomile oil effectively induced the resistance indicator enzymes in wheat and barley.

RACE1, a Japanese Blumeria graminis f. sp. hordei isolate, is capable of overcoming partially mlo-mediated penetration resistance in barley in an allele-specific manner.

Loss-of-function mutation of the MILDEW RESISTANCE LOCUS O (Mlo) gene confers durable and broad-spectrum resistance to powdery mildew fungi in various plants, including barley. In combination with the intracellular nucleotide-binding domain and leucine-rich repeat receptor (NLR) genes, which confer the race-specific resistance, the mlo alleles have long been used in barley breeding as genetic resources that confer robust non-race-specific resistance. However, a Japanese Blumeria graminis f. sp. hordei isolate, RACE1, has been reported to have the potential to overcome partially the mlo-mediated penetration resistance, although this is yet uncertain because the putative effects of NLR genes in the tested accessions have not been ruled out. In this study, we examined the reproducibility of the earlier report and found that the infectious ability of RACE1, which partially overcomes the mlo-mediated resistance, is only exerted in the absence of NLR genes recognizing RACE1. Furthermore, using the transient-induced gene silencing technique, we demonstrated that RACE1 can partially overcome the resistance in the host cells with suppressed MLO expression but not in plants possessing the null mutant allele mlo-5.

Phytohormonal and Transcriptomic Response of Hulless Barley Leaf in Response to Powdery Mildew Infection

Powdery mildew (PM) caused by Blumeria graminis (DC.) Golovin ex Speer f. sp. hordei Marchal (Bgh) is one of the major yield reducing diseases in hulless barley (Hordeum vulgare L. var. nudum Hook. f.). Genotypes with contrasting resistance to PM offer unique opportunities to explore the transcriptome in order to understand the expression changes in genes and pathways. In this study, we explored the phytohormone levels and transcriptome of a Bgh susceptible (XL19) and resistant (ZYM1288) hulless barley genotypes at 0, 5, 12, 24, and 36 h post infection (hpi) with Bgh. We found relatively higher levels of abscisic acid, jasmonic acid, salicylic acid, and cytokinins in ZYM1288. The transcriptome analyses identified 31,354 genes that were enriched in signaling, energy, and defense related pathways. Higher numbers of differentially expressed genes (DEGs) were found in XL19 as compared to ZYM1288 after 5 (3603 vs. 2341) and 12 hpi (3530 vs. 2416). However, after 24 and 36 hpi, the number of DEGs was higher in ZYM1288 as compared to XL19 i.e., 3625 vs. 3034 and 5855 vs. 2725, respectively. Changes in hormone levels drove downstream expression changes in plant-hormone signaling that helped ZYM1288 to perform better under Bgh infection. The expression of DEGs in MAPK-signaling and Toll-like receptor signaling pathways, glucosinolate biosynthesis, glutathione metabolism, brassinosteroid metabolism, and energy related pathways indicated their common roles in defense against PM. Key genes related to PM-resistance were upregulated in the resistant genotype. These genes provide key information towards differences in both genotypes towards resistance to PM. The transcriptomic signatures explored in this study will broaden our understanding towards molecular regulation of resistance to PM in hulless barley.