Characterizing the Pyrenophora teres f. maculata-Barley Interaction Using Pathogen Genetics.
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ABSTRACT:
SUBMITTER: Carlsen SA
PROVIDER: S-EPMC5555467 | biostudies-literature | 2017 Aug
REPOSITORIES: biostudies-literature
Publications
Characterizing the <i>Pyrenophora teres</i> f. <i>maculata</i>-Barley Interaction Using Pathogen Genetics.
Carlsen Steven A SA Neupane Anjan A Wyatt Nathan A NA Richards Jonathan K JK Faris Justin D JD Xu Steven S SS Brueggeman Robert S RS Friesen Timothy L TL
G3 (Bethesda, Md.) 20170807 8
<i>Pyrenophora teres</i> f. <i>maculata</i> is the cause of the foliar disease spot form net blotch (SFNB) on barley. To evaluate pathogen genetics underlying the <i>P. teres</i> f. <i>maculata</i>-barley interaction, we developed a 105-progeny population by crossing two globally diverse isolates, one from North Dakota and the other from Western Australia. Progeny were phenotyped on a set of four barley genotypes showing a differential reaction to the parental isolates, then genotyped using a re ...[more]
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Project description:Pyrenophora teres f. teres and P. teres f. maculata are significant pathogens that cause net blotch of barley. An increased number of loci involved in P. teres resistance or susceptibility responses of barley as well as interacting P. teres virulence effector loci have recently been identified through biparental and association mapping studies of both the pathogen and host. Characterization of the resistance/susceptibility loci in the host and the interacting effector loci in the pathogen will provide a path for targeted gene validation for better-informed release of resistant barley cultivars. This review assembles concise consensus maps for all loci published for both the host and pathogen, providing a useful resource for the community to be used in pathogen characterization and barley breeding for resistance to both forms of P. teres.
| S-EPMC6988421 | biostudies-literature
Project description:BACKGROUND: Pyrenophora teres f. teres is a necrotrophic fungal pathogen and the cause of one of barley's most important diseases, net form of net blotch. Here we report the first genome assembly for this species based solely on short Solexa sequencing reads of isolate 0-1. The assembly was validated by comparison to BAC sequences, ESTs, orthologous genes and by PCR, and complemented by cytogenetic karyotyping and the first genome-wide genetic map for P. teres f. teres. RESULTS: The total assembly was 41.95 Mbp and contains 11,799 gene models of 50 amino acids or more. Comparison against two sequenced BACs showed that complex regions with a high GC content assembled effectively. Electrophoretic karyotyping showed distinct chromosomal polymorphisms between isolates 0-1 and 15A, and cytological karyotyping confirmed the presence of at least nine chromosomes. The genetic map spans 2477.7 cM and is composed of 243 markers in 25 linkage groups, and incorporates simple sequence repeat markers developed from the assembly. Among predicted genes, non-ribosomal peptide synthetases and efflux pumps in particular appear to have undergone a P. teres f. teres-specific expansion of non-orthologous gene families. CONCLUSIONS: This study demonstrates that paired-end Solexa sequencing can successfully capture coding regions of a filamentous fungal genome. The assembly contains a plethora of predicted genes that have been implicated in a necrotrophic lifestyle and pathogenicity and presents a significant resource for examining the bases for P. teres f. teres pathogenicity.
| S-EPMC3156948 | biostudies-literature
Project description:Barley net form net blotch (NFNB), caused by the necrotrophic fungus Pyrenophora teres f. teres, is a destructive foliar disease in barley-growing regions worldwide. Little is known about the genetic and molecular basis of this pathosystem. Here, we identified a small secreted proteinaceous necrotrophic effector (NE), designated PttNE1, from intercellular wash fluids of the susceptible barley line Hector after inoculation with P.?teres f. teres isolate 0-1. Using a barley recombinant inbred line (RIL) population developed from a cross between the sensitive/susceptible line Hector and the insensitive/resistant line NDB 112 (HN population), sensitivity to PttNE1, which we have named SPN1, mapped to a common resistance/susceptibility region on barley chromosome 6H. PttNE1-SPN1 interaction accounted for 31% of the disease variation when the HN population was inoculated with the 0-1 isolate. Strong accumulation of hydrogen peroxide and increased levels of electrolyte leakage were associated with the susceptible reaction, but not the resistant reaction. In addition, the HN RIL population was evaluated for its reactions to 10 geographically diverse P.?teres f. teres isolates. Quantitative trait locus (QTL) mapping led to the identification of at least 10 genomic regions associated with disease, with chromosomes 3H and 6H harbouring major QTLs for resistance/susceptibility. SPN1 was associated with all the 6H QTLs, except one. Collectively, this information indicates that the barley-P.?teres f. teres pathosystem follows, at least partially, an NE-triggered susceptibility (NETS) model that has been described in other necrotrophic fungal disease systems, especially in the Dothideomycete class of fungi.
| S-EPMC6638325 | biostudies-literature
Project description:BackgroundPathogens evolve in an arms race, frequently evolving virulence that defeats resistance genes in their hosts. Infection of multiple hosts may accelerate this virulence evolution. Theory predicts that host diversity affects pathogen diversity, with more diverse hosts expected to harbour more diverse pathogens that reproduce sexually. We tested this hypothesis by comparing the microsatellite (SSR) genetic diversity of the barley leaf pathogen Pyrenophora teres f. teres (Ptt) from barley (monoculture) and barley grass (outbreeding). We also aim to investigate host specificity and attempt to track virulence on two barley cultivars, Maritime and Keel.ResultsGenetic diversity in barley Ptt populations was higher than in populations from barley grass. Barley Ptt populations also had higher linkage disequilibrium levels, indicating less frequent sexual reproduction, consistent with the Red Queen hypothesis theory that genetically diverse hosts should select for higher levels of sexual reproduction of the pathogen. SSR analyses indicate that host-associated Ptt populations do not share genotypes and have independent evolutionary histories. Pathogenicity studies showed host specificity as host-associated Ptt isolates could not cross-infect hosts. Minimum spanning network analyses indicated two major clusters of barley Ptt. One cluster represents Maritime virulent and isolates from Western Australia (WA). Low PhiPt population differentiation between WA populations and those from Maritime and Keel, indicated a WA origin of the Maritime and Keel virulences. The main minimum spanning network cluster is represented by a panmictic population structure, represented by isolates from all over Australia.ConclusionsAlthough barley Ptt populations are more diverse than barley grass Ptt populations, this may be a result of the size and number of founder Ptt populations to Australia, with larger and more barley Ptt populations introduced. More frequent sexual reproduction of Ptt on barley grass support the Red Queen Hypothesis and suggest evolutionary potential of pathogens on diverse hosts are high. Extensive gene flow of Ptt between regions in Australia is suggested to maintain a panmictic population structure, with human-mediated dispersal aiding in virulence evolution of Ptt on barley.
| S-EPMC6615293 | biostudies-literature
Project description:BACKGROUND:Net blotch caused by Pyrenophra teres f. teres is a major foliar disease of barley. Infection can result in significant yield losses of susceptible cultivars of up to 40%. Of the two forms of net blotch (P. teres f. teres and P. teres f. maculata), P. teres f. teres (net form of net blotch) is the dominant one in Russia. The goal of the current study was to identify genomic regions associated with seedling resistance to several pathotypes of the net form of net blotch in Siberian spring barley genotypes. For this, a genome-wide association study of a Siberian barley collection, genotyped with 50?K Illumina SNP-chip, was carried out. RESULTS:Seedling resistance of 94 spring barley cultivars and lines to four Pyrenophora teres f. teres isolates (S10.2, K5.1, P3.4.0, and A2.6.0) was investigated. According to the Tekauz rating scale, 25, 21, 14, and 14% of genotypes were highly resistant, and 19, 8, 9, and 16% of genotypes were moderate-resistant to the isolates S10.2, K5.1, P3.4.0, and A2.6.0, respectively. Eleven genotypes (Alag-Erdene, Alan-Bulag, L-259/528, Kedr, Krymchak 55, Omsky golozyorny 2, Omsky 13709, Narymchanin, Pallidum 394, Severny and Viner) were resistant to all studied isolates. Nine additional cultivars (Aley, Barkhatny, Belogorsky, Bezenchuksky 2, Emelya, G-19980, Merit 57, Mestny Primorsky, Slavaynsky) were resistant to 3 of the 4 isolates. The phenotyping and genotyping data were analysed using several statistical models: GLM?+?Q, GLM?+?PCA, GLM?+?PCA?+?Q, and the MLM?+?kinship matrix. In total, 40 SNPs in seven genomic regions associated with net blotch resistance were revealed: the region on chromosome 1H between 57.3 and 62.8?cM associated with resistance to 2 isolates (to P3.4.0 at the significant and K5.1 at the suggestive levels), the region on chromosome 6H between 52.6 and 55.4?cM associated with resistance to 3 isolates (to P3.4.0 at the significant and K5.1 and S10.2 at the suggestive levels), three isolate-specific significant regions (P3.4.0-specific regions on chromosome 2H between 71.0 and 74.1?cM and on chromosome 3H between 12.1 and 17.4?cM, and the A2.6.0-specific region on chromosome 3H between 50.9 and 54.8?cM), as well as two additional regions on chromosomes 2H (between 23.2 and 23.8?cM, resistant to S10.2) and 3 (between 135.6 and 137.5?cM resistant to K5.1) with suggestive SNPs, coinciding, however, with known net blotch resistance quantitative trait loci (QTLs) at the same regions. CONCLUSIONS:Seven genomic regions on chromosomes 1H, 2H, 3H, and 6H associated with the resistance to four Pyrenophora teres f. teres isolates were identified in a genome-wide association study of a Siberian spring barley panel. One novel isolate-specific locus on chromosome 3 between 12.1 and 17.4?cM was revealed. Other regions identified in the current study coincided with previously known loci conferring resistance to net blotch. The significant SNPs revealed in the current study can be converted to convenient PCR markers for accelerated breeding of resistant barley cultivars.
| S-EPMC7227216 | biostudies-literature
Project description:Spot form net blotch (SFNB), caused by the necrotrophic fungal pathogen Pyrenophora teres f. maculata (Ptm), is a foliar disease of barley that results in significant yield losses in major growing regions worldwide. Understanding the host-parasite interactions between pathogen virulence/avirulence genes and the corresponding host susceptibility/resistance genes is important for the deployment of genetic resistance against SFNB. Two recombinant inbred mapping populations were developed to characterize genetic resistance/susceptibility to the Ptm isolate 13IM8.3, which was collected from Idaho (ID). An Illumina Infinium array was used to produce a genome-wide marker set. Quantitative trait loci (QTL) analysis identified ten significant resistance/susceptibility loci, with two of the QTL being common to both populations. One of the QTL on 5H appears to be novel, while the remaining loci have been reported previously. Single nucleotide polymorphisms (SNPs) closely linked to or delimiting the significant QTL have been converted to user-friendly markers. Loci and associated molecular markers identified in this study will be useful in genetic mapping and deployment of the genetic resistance to SFNB in barley.
| S-EPMC8664462 | biostudies-literature
Project description:Barley net- and spot-form of net blotch disease are caused by two formae of the hemibiotrophic fungus Pyrenophora teres (P. t. f. teres and P. t. f. maculata). In the present study, suppression subtractive hybridization (SSH) was used in combination with quantitative real-time reverse transcriptase PCR to identify and profile the expression of defence response (DR) genes in the early stages of both barley-P. teres incompatible and compatible interactions. From a pool of 307 unique gene transcripts identified by SSH, 45 candidate DR genes were selected for temporal expression profiling in infected leaf epidermis. Differential expression profiles were observed for 28 of the selected candidates, which were grouped into clusters depending on their expression profiles within the first 48 h after inoculation. The expression profiles characteristic of each gene cluster were very similar in both barley-P. t. f. teres and barley-P. t. f. maculata interactions, indicating that resistance to both pathogens could be mediated by induction of the same group of DR genes. Chromosomal map locations for 21 DR genes were identified using four doubled-haploid mapping populations. The mapped DR genes were distributed across all seven barley chromosomes, with at least one gene mapping to within 15 cM of another on chromosomes 1H, 2H, 5H and 7H. Additionally, some DR genes appeared to co-localize with loci harbouring known resistance genes or quantitative trait loci for net blotch resistance on chromosomes 6H and 7H, as well as loci associated with resistance to other barley diseases. The DR genes are discussed with respect to their map locations and potential functional role in contributing to net blotch disease resistance.
| S-EPMC6640259 | biostudies-literature
Project description:BackgroundSpot form net blotch (SFNB) caused by the necrotrophic fungal pathogen Pyrenophora teres f. maculata (Ptm) is an economically important disease of barley that also infects wheat. Using genetic analysis to characterize loci in Ptm genomes associated with virulence or avirulence is an important step to identify pathogen effectors that determine compatible (virulent) or incompatible (avirulent) interactions with cereal hosts. Association mapping (AM) is a powerful tool for detecting virulence loci utilizing phenotyping and genotyping data generated for natural populations of plant pathogenic fungi.ResultsRestriction-site associated DNA genotyping-by-sequencing (RAD-GBS) was used to generate 4,836 single nucleotide polymorphism (SNP) markers for a natural population of 103 Ptm isolates collected from Idaho, Montana and North Dakota. Association mapping analyses were performed utilizing the genotyping and infection type data generated for each isolate when challenged on barley seedlings of thirty SFNB differential barley lines. A total of 39 marker trait associations (MTAs) were detected across the 20 barley lines corresponding to 30 quantitative trait loci (QTL); 26 novel QTL and four that were previously mapped in Ptm biparental populations. These results using diverse US isolates and barley lines showed numerous barley-Ptm genetic interactions with seven of the 30 Ptm virulence/avirulence loci falling on chromosome 3, suggesting that it is a reservoir of diverse virulence effectors. One of the loci exhibited reciprocal virulence/avirulence with one haplotype predominantly present in isolates collected from Idaho increasing virulence on barley line MXB468 and the alternative haplotype predominantly present in isolates collected from North Dakota and Montana increasing virulence on barley line CI9819.ConclusionsAssociation mapping provided novel insight into the host pathogen genetic interactions occurring in the barley-Ptm pathosystem. The analysis suggests that chromosome 3 of Ptm serves as an effector reservoir in concordance with previous reports for Pyrenophora teres f. teres, the causal agent of the closely related disease net form net blotch. Additionally, these analyses identified the first reported case of a reciprocal pathogen virulence locus. However, further investigation of the pathosystem is required to determine if multiple genes or alleles of the same gene are responsible for this genetic phenomenon.
| S-EPMC8994276 | biostudies-literature
Project description:Barley is an important cereal crop worldwide because of its use in the brewing and distilling industry. However, adequate supplies of quality malting barley are threatened by global climate change due to drought in some regions and excess precipitation in others, which facilitates epidemics caused by fungal pathogens. The disease net form net blotch caused by the necrotrophic fungal pathogen Pyrenophora teres f. teres (Ptt) has emerged as a global threat to barley production and diverse populations of Ptt have shown a capacity to overcome deployed genetic resistances. The barley line CI5791 exhibits remarkably effective resistance to diverse Ptt isolates from around the world that maps to two major QTL on chromosomes 3H and 6H. To identify genes involved in this effective resistance, CI5791 seed were γ-irradiated and two mutants, designated CI5791-γ3 and CI5791-γ8, with compromised Ptt resistance were identified from an M2 population. Phenotyping of CI5791-γ3 and -γ8 × Heartland F2 populations showed three resistant to one susceptible segregation ratios and CI5791-γ3 × -γ8 F1 individuals were susceptible, thus these independent mutants are in a single allelic gene. Thirty-four homozygous mutant (susceptible) CI5791-γ3 × Heartland F2 individuals, representing 68 recombinant gametes, were genotyped via PCR genotype by sequencing. The data were used for single marker regression mapping placing the mutation on chromosome 3H within an approximate 75 cM interval encompassing the 3H CI5791 resistance QTL. Sequencing of the mutants and wild-type (WT) CI5791 genomic DNA following exome capture identified independent mutations of the HvWRKY6 transcription factor located on chromosome 3H at ∼50.7 cM, within the genetically delimited region. Post transcriptional gene silencing of HvWRKY6 in barley line CI5791 resulted in Ptt susceptibility, confirming that it functions in NFNB resistance, validating it as the gene underlying the mutant phenotypes. Allele analysis and transcript regulation of HvWRKY6 from resistant and susceptible lines revealed sequence identity and upregulation upon pathogen challenge in all genotypes analyzed, suggesting a conserved transcription factor is involved in the defense against the necrotrophic pathogen. We hypothesize that HvWRKY6 functions as a conserved signaling component of defense mechanisms that restricts Ptt growth in barley.
| S-EPMC7844392 | biostudies-literature
Project description:Pyrenophora teres f. maculata strain:13IM8 Genome sequencing
| PRJNA1031594 | ENA