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Million CR, Wijeratne S, Karhoff S, Cassone BJ, McHale LK, Dorrance AE. Molecular mechanisms underpinning quantitative resistance to Phytophthora sojae in Glycine max using a systems genomics approach. FRONTIERS IN PLANT SCIENCE 2023; 14:1277585. [PMID: 38023885 PMCID: PMC10662313 DOI: 10.3389/fpls.2023.1277585] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
Expression of quantitative disease resistance in many host-pathogen systems is controlled by genes at multiple loci, each contributing a small effect to the overall response. We used a systems genomics approach to study the molecular underpinnings of quantitative disease resistance in the soybean-Phytophthora sojae pathosystem, incorporating expression quantitative trait loci (eQTL) mapping and gene co-expression network analysis to identify the genes putatively regulating transcriptional changes in response to inoculation. These findings were compared to previously mapped phenotypic (phQTL) to identify the molecular mechanisms contributing to the expression of this resistance. A subset of 93 recombinant inbred lines (RILs) from a Conrad × Sloan population were inoculated with P. sojae isolate 1.S.1.1 using the tray-test method; RNA was extracted, sequenced, and the normalized read counts were genetically mapped from tissue collected at the inoculation site 24 h after inoculation from both mock and inoculated samples. In total, more than 100,000 eQTLs were mapped. There was a switch from predominantly cis-eQTLs in the mock treatment to an almost entirely nonoverlapping set of predominantly trans-eQTLs in the inoculated treatment, where greater than 100-fold more eQTLs were mapped relative to mock, indicating vast transcriptional reprogramming due to P. sojae infection occurred. The eQTLs were organized into 36 hotspots, with the four largest hotspots from the inoculated treatment corresponding to more than 70% of the eQTLs, each enriched for genes within plant-pathogen interaction pathways. Genetic regulation of trans-eQTLs in response to the pathogen was predicted to occur through transcription factors and signaling molecules involved in plant-pathogen interactions, plant hormone signal transduction, and MAPK pathways. Network analysis identified three co-expression modules that were correlated with susceptibility to P. sojae and associated with three eQTL hotspots. Among the eQTLs co-localized with phQTLs, two cis-eQTLs with putative functions in the regulation of root architecture or jasmonic acid, as well as the putative master regulators of an eQTL hotspot nearby a phQTL, represent candidates potentially underpinning the molecular control of these phQTLs for resistance.
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Affiliation(s)
- Cassidy R. Million
- Department of Plant Pathology, The Ohio State University, Wooster, OH, United States
- Center for Soybean Research and Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
| | - Saranga Wijeratne
- Molecular and Cellular Imaging Center, The Ohio State University, Wooster, OH, United States
| | - Stephanie Karhoff
- Center for Soybean Research and Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
- Translational Plant Sciences Graduate Program, The Ohio State University, Columbus, OH, United States
| | - Bryan J. Cassone
- Center for Soybean Research and Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
- Department of Biology, Brandon University, Brandon, Manitoba, MB, Canada
| | - Leah K. McHale
- Center for Soybean Research and Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, United States
| | - Anne E. Dorrance
- Department of Plant Pathology, The Ohio State University, Wooster, OH, United States
- Center for Soybean Research and Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, United States
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2
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Krishnan P, Caseys C, Soltis N, Zhang W, Burow M, Kliebenstein DJ. Polygenic pathogen networks influence transcriptional plasticity in the Arabidopsis-Botrytis pathosystem. Genetics 2023; 224:iyad099. [PMID: 37216906 PMCID: PMC10789313 DOI: 10.1093/genetics/iyad099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 03/30/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023] Open
Abstract
Bidirectional flow of information shapes the outcome of the host-pathogen interactions and depends on the genetics of each organism. Recent work has begun to use co-transcriptomic studies to shed light on this bidirectional flow, but it is unclear how plastic the co-transcriptome is in response to genetic variation in both the host and pathogen. To study co-transcriptome plasticity, we conducted transcriptomics using natural genetic variation in the pathogen, Botrytis cinerea, and large-effect genetic variation abolishing defense signaling pathways within the host, Arabidopsis thaliana. We show that genetic variation in the pathogen has a greater influence on the co-transcriptome than mutations that abolish defense signaling pathways in the host. Genome-wide association mapping using the pathogens' genetic variation and both organisms' transcriptomes allowed an assessment of how the pathogen modulates plasticity in response to the host. This showed that the differences in both organism's responses were linked to trans-expression quantitative trait loci (eQTL) hotspots within the pathogen's genome. These hotspots control gene sets in either the host or pathogen and show differential allele sensitivity to the host's genetic variation rather than qualitative host specificity. Interestingly, nearly all the trans-eQTL hotspots were unique to the host or pathogen transcriptomes. In this system of differential plasticity, the pathogen mediates the shift in the co-transcriptome more than the host.
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Affiliation(s)
- Parvathy Krishnan
- DynaMo Center of Excellence, University of Copenhagen, Copenhagen DL-1165Denmark
| | - Celine Caseys
- Department of Plant Sciences, University of California Davis, Davis, CA 95616USA
| | - Nik Soltis
- Department of Plant Sciences, University of California Davis, Davis, CA 95616USA
| | - Wei Zhang
- Department of Botany & Plant Sciences, Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Meike Burow
- DynaMo Center of Excellence, University of Copenhagen, Copenhagen DL-1165Denmark
| | - Daniel J Kliebenstein
- DynaMo Center of Excellence, University of Copenhagen, Copenhagen DL-1165Denmark
- Department of Plant Sciences, University of California Davis, Davis, CA 95616USA
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McNinch C, Chen K, Dennison T, Lopez M, Yandeau-Nelson MD, Lauter N. A multigenotype maize silk expression atlas reveals how exposure-related stresses are mitigated following emergence from husk leaves. THE PLANT GENOME 2020; 13:e20040. [PMID: 33090730 DOI: 10.1002/tpg2.20040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/11/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
The extraordinarily long stigmatic silks of corn (Zea mays L.) are critical for grain production but the biology of their growth and emergence from husk leaves has remained underexplored. Accordingly, gene expression was assayed for inbreds 'B73' and 'Mo17' across five contiguous silk sections. Half of the maize genes (∼20,000) are expressed in silks, mostly in spatiotemporally dynamic patterns. In particular, emergence triggers strong differential expression of ∼1,500 genes collectively enriched for gene ontology terms associated with abiotic and biotic stress responses, hormone signaling, cell-cell communication, and defense metabolism. Further, a meta-analysis of published maize transcriptomic studies on seedling stress showed that silk emergence elicits an upregulated transcriptomic response that overlaps strongly with both abiotic and biotic stress responses. Although the two inbreds revealed similar silk transcriptomic programs overall, genotypic expression differences were observed for 5,643 B73-Mo17 syntenic gene pairs and collectively account for >50% of genome-wide expression variance. Coexpression clusters, including many based on genotypic divergence, were identified and interrogated via ontology-term enrichment analyses to generate biological hypotheses for future research. Ultimately, dissecting how gene expression changes along the length of silks and between husk-encased and emerged states offers testable models for silk development and plant response to environmental stresses.
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Affiliation(s)
- Colton McNinch
- Molecular, Cellular, and Developmental Biology Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
| | - Keting Chen
- Bioinformatics & Computational Biology Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
| | - Tesia Dennison
- Genetics & Genomics Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
| | - Miriam Lopez
- USDA-ARS Corn Insects and Crop Genetics Research Unit, Iowa State Univ., Ames, IA, 50011, USA
| | - Marna D Yandeau-Nelson
- Molecular, Cellular, and Developmental Biology Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
- Bioinformatics & Computational Biology Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
- Genetics & Genomics Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
- Department of Genetics, Development and Cell Biology, Iowa State Univ., Ames, IA, 50011, USA
| | - Nick Lauter
- Molecular, Cellular, and Developmental Biology Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
- Genetics & Genomics Graduate Program, Iowa State Univ., Ames, IA, 50011, USA
- USDA-ARS Corn Insects and Crop Genetics Research Unit, Iowa State Univ., Ames, IA, 50011, USA
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4
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Weiss M, Sniezko RA, Puiu D, Crepeau MW, Stevens K, Salzberg SL, Langley CH, Neale DB, De La Torre AR. Genomic basis of white pine blister rust quantitative disease resistance and its relationship with qualitative resistance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:365-376. [PMID: 32654344 PMCID: PMC10773528 DOI: 10.1111/tpj.14928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/17/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
The genomic architecture and molecular mechanisms controlling variation in quantitative disease resistance loci are not well understood in plant species and have been barely studied in long-generation trees. Quantitative trait loci mapping and genome-wide association studies were combined to test a large single nucleotide polymorphism (SNP) set for association with quantitative and qualitative white pine blister rust resistance in sugar pine. In the absence of a chromosome-scale reference genome, a high-density consensus linkage map was generated to obtain locations for associated SNPs. Newly discovered associations for white pine blister rust quantitative disease resistance included 453 SNPs involved in wide biological functions, including genes associated with disease resistance and others involved in morphological and developmental processes. In addition, NBS-LRR pathogen recognition genes were found to be involved in quantitative disease resistance, suggesting these newly reported genes are qualitative genes with partial resistance, they are the result of defeated qualitative resistance due to avirulent races, or they have epistatic effects on qualitative disease resistance genes. This study is a step forward in our understanding of the complex genomic architecture of quantitative disease resistance in long-generation trees, and constitutes the first step towards marker-assisted disease resistance breeding in white pine species.
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Affiliation(s)
- Matthew Weiss
- School of Forestry, Northern Arizona University, 200 E.
Pine Knoll, Flagstaff, AZ 86011
| | - Richard A. Sniezko
- Dorena Genetic Resource Center, USDA Forest Service,
Cottage-Grove, OR 97424
| | - Daniela Puiu
- Department of Biomedical Engineering, Computer Science and
Biostatistics and Center for Computational Biology, Johns Hopkins University, 3100
Wyman Park Dr., Wyman Park Building Room S220, Baltimore, MD 21211
| | - Marc W. Crepeau
- Department of Evolution and Ecology, University of
California-Davis, One Shields Avenue, Davis, CA 95616
| | - Kristian Stevens
- Department of Evolution and Ecology, University of
California-Davis, One Shields Avenue, Davis, CA 95616
| | - Steven L. Salzberg
- Department of Biomedical Engineering, Computer Science and
Biostatistics and Center for Computational Biology, Johns Hopkins University, 3100
Wyman Park Dr., Wyman Park Building Room S220, Baltimore, MD 21211
- Departments of Computer Science and Biostatistics, Johns
Hopkins University, Baltimore, MD 21218
| | - Charles H. Langley
- Department of Evolution and Ecology, University of
California-Davis, One Shields Avenue, Davis, CA 95616
| | - David B. Neale
- Department of Plant Sciences, University of
California-Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Amanda R. De La Torre
- School of Forestry, Northern Arizona University, 200 E.
Pine Knoll, Flagstaff, AZ 86011
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5
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Delplace F, Huard-Chauveau C, Dubiella U, Khafif M, Alvarez E, Langin G, Roux F, Peyraud R, Roby D. Robustness of plant quantitative disease resistance is provided by a decentralized immune network. Proc Natl Acad Sci U S A 2020; 117:18099-18109. [PMID: 32669441 PMCID: PMC7395444 DOI: 10.1073/pnas.2000078117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Quantitative disease resistance (QDR) represents the predominant form of resistance in natural populations and crops. Surprisingly, very limited information exists on the biomolecular network of the signaling machineries underlying this form of plant immunity. This lack of information may result from its complex and quantitative nature. Here, we used an integrative approach including genomics, network reconstruction, and mutational analysis to identify and validate molecular networks that control QDR in Arabidopsis thaliana in response to the bacterial pathogen Xanthomonas campestris To tackle this challenge, we first performed a transcriptomic analysis focused on the early stages of infection and using transgenic lines deregulated for the expression of RKS1, a gene underlying a QTL conferring quantitative and broad-spectrum resistance to XcampestrisRKS1-dependent gene expression was shown to involve multiple cellular activities (signaling, transport, and metabolism processes), mainly distinct from effector-triggered immunity (ETI) and pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) responses already characterized in Athaliana Protein-protein interaction network reconstitution then revealed a highly interconnected and distributed RKS1-dependent network, organized in five gene modules. Finally, knockout mutants for 41 genes belonging to the different functional modules of the network revealed that 76% of the genes and all gene modules participate partially in RKS1-mediated resistance. However, these functional modules exhibit differential robustness to genetic mutations, indicating that, within the decentralized structure of the QDR network, some modules are more resilient than others. In conclusion, our work sheds light on the complexity of QDR and provides comprehensive understanding of a QDR immune network.
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Affiliation(s)
- Florent Delplace
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
| | - Carine Huard-Chauveau
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
| | - Ullrich Dubiella
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
- KWS SAAT SE & Co, 37574 Einbeck, Germany
| | - Mehdi Khafif
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
| | - Eva Alvarez
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
| | - Gautier Langin
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
| | - Fabrice Roux
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
| | - Rémi Peyraud
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France
- iMean, 31520 Toulouse, France
| | - Dominique Roby
- Laboratoire des Interactions Plantes-Microorganismes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, 31326 Castanet-Tolosan, France;
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6
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Barbacci A, Navaud O, Mbengue M, Barascud M, Godiard L, Khafif M, Lacaze A, Raffaele S. Rapid identification of an Arabidopsis NLR gene as a candidate conferring susceptibility to Sclerotinia sclerotiorum using time-resolved automated phenotyping. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:903-917. [PMID: 32170798 PMCID: PMC7497225 DOI: 10.1111/tpj.14747] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/25/2020] [Accepted: 02/28/2020] [Indexed: 05/11/2023]
Abstract
The broad host range necrotrophic fungus Sclerotinia sclerotiorum is a devastating pathogen of many oil and vegetable crops. Plant genes conferring complete resistance against S. sclerotiorum have not been reported. Instead, plant populations challenged by S. sclerotiorum exhibit a continuum of partial resistance designated as quantitative disease resistance (QDR). Because of their complex interplay and their small phenotypic effect, the functional characterization of QDR genes remains limited. How broad host range necrotrophic fungi manipulate plant programmed cell death is for instance largely unknown. Here, we designed a time-resolved automated disease phenotyping pipeline enabling high-throughput disease lesion measurement with high resolution, low footprint at low cost. We could accurately recover contrasted disease responses in several pathosystems using this system. We used our phenotyping pipeline to assess the kinetics of disease symptoms caused by seven S. sclerotiorum isolates on six A. thaliana natural accessions with unprecedented resolution. Large effect polymorphisms common to the most resistant A. thaliana accessions identified highly divergent alleles of the nucleotide-binding site leucine-rich repeat gene LAZ5 in the resistant accessions Rubezhnoe and Lip-0. We show that impaired LAZ5 expression in laz5.1 mutant lines and in A. thaliana Rub natural accession correlate with enhanced QDR to S. sclerotiorum. These findings illustrate the value of time-resolved image-based phenotyping for unravelling the genetic bases of complex traits such as QDR. Our results suggest that S. sclerotiorum manipulates plant sphingolipid pathways guarded by LAZ5 to trigger programmed cell death and cause disease.
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Affiliation(s)
- Adelin Barbacci
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
| | - Olivier Navaud
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
| | - Malick Mbengue
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
| | - Marielle Barascud
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
| | - Laurence Godiard
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
| | - Mehdi Khafif
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
| | - Aline Lacaze
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
| | - Sylvain Raffaele
- Laboratoire des Interactions Plantes Micro-organismes (LIPM)Université de ToulouseINRAECNRS24 chemin de Borde Rouge - Auzeville CS 52627 F31326Castanet TolosanCedexFrance
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7
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Hernandez J, Del Blanco A, Filichkin T, Fisk S, Gallagher L, Helgerson L, Meints B, Mundt C, Steffenson B, Hayes P. A Genome-Wide Association Study of Resistance to Puccinia striiformis f. sp. hordei and P. graminis f. sp. tritici in Barley and Development of Resistant Germplasm. PHYTOPATHOLOGY 2020; 110:1082-1092. [PMID: 32023173 DOI: 10.1094/phyto-11-19-0415-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Stripe rust (incited by Puccinia striiformis f. sp. hordei) and stem rust (incited by P. graminis f. sp. tritici) are two of the most important diseases affecting barley. Building on prior work involving the introgression of the resistance genes rpg4/Rpg5 into diverse genetic backgrounds and the discovery of additional quantitative trait locus (QTLs) for stem rust resistance, we generated an array of germplasm in which we mapped resistance to stripe rust and stem rust. Stem rust races TTKSK and QCCJB were used for resistance mapping at the seedling and adult plant stages, respectively. Resistance to stripe rust, at the adult plant stage, was determined by QTLs on chromosomes 1H, 4H, and 5H that were previously reported in the literature. The rpg4/Rpg5 complex was validated as a source of resistance to stem rust at the seedling stage. Some parental germplasm, selected as potentially resistant to stem rust or susceptible but having other positive attributes, showed resistance at the seedling stage, which appears to be allelic to rpg4/Rpg5. The rpg4/Rpg5 complex, and this new allele, were not sufficient for adult plant resistance to stem rust in one environment. A QTL on 5H, distinct from Rpg5 and a previously reported resistance QTL, was required for resistance at the adult plant stage in all environments. This QTL is coincident with the QTL for stripe rust resistance. Germplasm with mapped genes/QTLs conferring resistance to stripe and stem rust was identified and is available as a resource to the research and breeding communities.
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Affiliation(s)
- Javier Hernandez
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Alicia Del Blanco
- Department of Plant Sciences, University of California-Davis, Davis, CA 95616
| | - Tanya Filichkin
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Scott Fisk
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Lynn Gallagher
- Department of Plant Sciences, University of California-Davis, Davis, CA 95616
| | - Laura Helgerson
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Brigid Meints
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Chris Mundt
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Brian Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108
| | - Patrick Hayes
- Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
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Hernandez J, Steffenson BJ, Filichkin T, Fisk SP, Helgerson L, Meints B, Vining KJ, Marshall D, Del Blanco A, Chen X, Hayes PM. Introgression of rpg4/ Rpg5 Into Barley Germplasm Provides Insights Into the Genetics of Resistance to Puccinia graminis f. sp. tritici Race TTKSK and Resources for Developing Resistant Cultivars. PHYTOPATHOLOGY 2019; 109:1018-1028. [PMID: 30714882 DOI: 10.1094/phyto-09-18-0350-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Stem rust (incited by Puccinia graminis f. sp. tritici) is a devastating disease of wheat and barley in many production areas. The widely virulent African P. graminis f. sp. tritici race TTKSK is of particular concern, because most cultivars are susceptible. To prepare for the possible arrival of race TTKSK in North America, we crossed a range of barley germplasm-representing different growth habits and end uses-with donors of stem rust resistance genes Rpg1 and rpg4/Rpg5. The former confers resistance to prevalent races of P. graminis f. sp. tritici in North America, and the latter confers resistance to TTKSK and other closely related races from Africa. We produced doubled haploids from these crosses and determined their allele type at the Rpg loci and haplotype at 7,864 single-nucleotide polymorphism loci. The doubled haploids were phenotyped for TTKSK resistance at the seedling stage. Integration of genotype and phenotype data revealed that (i) Rpg1 was not associated with TTKSK resistance, (ii) rpg4/Rpg5 was necessary but was not sufficient for resistance, and (iii) specific haplotypes at two quantitative trait loci were required for rpg4/Rpg5 to confer resistance to TTKSK. To confirm whether lines found resistant to TTKSK at the seedling resistance were also resistant at the adult plant stage, a subset of doubled haploids was evaluated in Kenya. Additionally, adult plant resistance to leaf rust and stripe rust (incited by Puccinia hordei and Puccinia striiformis f. sp. hordei, respectively) was also assessed on the doubled haploids in field trials at three locations in the United States over a 2-year period. Doubled haploids were identified with adult plant resistance to all three rusts, and this germplasm is available to the research and breeding communities.
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Affiliation(s)
- Javier Hernandez
- 1 Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Brian J Steffenson
- 2 Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108
| | - Tanya Filichkin
- 1 Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Scott P Fisk
- 1 Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Laura Helgerson
- 1 Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Brigid Meints
- 1 Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
| | - Kelly J Vining
- 3 Department of Horticulture, Oregon State University, Corvallis, OR 97331
| | - David Marshall
- 4 U.S. Department of Agriculture Agricultural Research Service, Raleigh, NC 27695
| | - Alicia Del Blanco
- 5 Department of Plant Sciences, University of California, Davis, CA 95616
| | - Xianming Chen
- 6 U.S. Department of Agriculture Agricultural Research Service Wheat Health, Genetics, and Quality Research Unit and Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430
| | - Patrick M Hayes
- 1 Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331
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9
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Tanaka T, Ishikawa G, Ogiso-Tanaka E, Yanagisawa T, Sato K. Development of Genome-Wide SNP Markers for Barley via Reference- Based RNA-Seq Analysis. FRONTIERS IN PLANT SCIENCE 2019; 10:577. [PMID: 31134117 PMCID: PMC6523396 DOI: 10.3389/fpls.2019.00577] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Marker-assisted selection of crop plants requires DNA markers that can distinguish between the closely related strains often used in breeding. The availability of reference genome sequence facilitates the generation of markers, by elucidating the genomic positions of new markers as well as of their neighboring sequences. In 2017, a high quality genome sequence was released for the six-row barley (Hordeum vulgare) cultivar Morex. Here, we developed a de novo RNA-Seq-based genotyping procedure for barley strains used in Japanese breeding programs. Using RNA samples from the seedling shoot, seedling root, and immature flower spike, we mapped next-generation sequencing reads onto the transcribed regions, which correspond to ∼590 Mb of the whole ∼4.8-Gbp reference genome sequence. Using 150 samples from 108 strains, we detected 181,567 SNPs and 45,135 indels located in the 28,939 transcribed regions distributed throughout the Morex genome. We evaluated the quality of this polymorphism detection approach by analyzing 387 RNA-Seq-derived SNPs using amplicon sequencing. More than 85% of the RNA-Seq SNPs were validated using the highly redundant reads from the amplicon sequencing, although half of the indels and multiple-allele loci showed different polymorphisms between the platforms. These results demonstrated that our RNA-Seq-based de novo polymorphism detection system generates genome-wide markers, even in the closely related barley genotypes used in breeding programs.
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Affiliation(s)
- Tsuyoshi Tanaka
- Breeding Informatics Research Unit, Division of Basic Research, Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
- Bioinformatics Team, Advanced Analysis Center, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
- Advanced Agricultural Technology and Sciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Goro Ishikawa
- Breeding Strategies Research Unit, Division of Basic Research, Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
| | - Eri Ogiso-Tanaka
- Soybean and Field Crop Applied Genomics Research Unit, Division of Field Crop Research, Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
| | - Takashi Yanagisawa
- Wheat and Barley Breeding Unit, Division of Wheat and Barley Research, Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
| | - Kazuhiro Sato
- Group of Genome Diversity, Institute of Plant Science and Resources, Okayama University, Okayama, Japan
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Davis JL, Armengaud P, Larson TR, Graham IA, White PJ, Newton AC, Amtmann A. Contrasting nutrient-disease relationships: Potassium gradients in barley leaves have opposite effects on two fungal pathogens with different sensitivities to jasmonic acid. PLANT, CELL & ENVIRONMENT 2018; 41:2357-2372. [PMID: 29851096 PMCID: PMC6175101 DOI: 10.1111/pce.13350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/21/2018] [Indexed: 05/20/2023]
Abstract
Understanding the interactions between mineral nutrition and disease is essential for crop management. Our previous studies with Arabidopsis thaliana demonstrated that potassium (K) deprivation induced the biosynthesis of jasmonic acid (JA) and increased the plant's resistance to herbivorous insects. Here, we addressed the question of how tissue K affects the development of fungal pathogens and whether sensitivity of the pathogens to JA could play a role for the K-disease relationship in barley (Hordeum vulgare cv. Optic). We report that K-deprived barley plants showed increased leaf concentrations of JA and other oxylipins. Furthermore, a natural tip-to-base K-concentration gradient within leaves of K-sufficient plants was quantitatively mirrored by the transcript levels of JA-responsive genes. The local leaf tissue K concentrations affected the development of two economically important fungi in opposite ways, showing a positive correlation with powdery mildew (Blumeria graminis) and a negative correlation with leaf scald (Rhynchosporium commune) disease symptoms. B. graminis induced a JA response in the plant and was sensitive to methyl-JA treatment whereas R. commune initiated no JA response and was JA insensitive. Our study challenges the view that high K generally improves plant health and suggests that JA sensitivity of pathogens could be an important factor in determining the exact K-disease relationship.
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Affiliation(s)
- Jayne L. Davis
- Plant Science Group, Institute for Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
- Ecological SciencesThe James Hutton InstituteDundeeUK
| | - Patrick Armengaud
- Plant Science Group, Institute for Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Tony R. Larson
- Department of Biology, Centre for Novel Agricultural ProductsUniversity of YorkYorkUK
| | - Ian A. Graham
- Department of Biology, Centre for Novel Agricultural ProductsUniversity of YorkYorkUK
| | | | | | - Anna Amtmann
- Plant Science Group, Institute for Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
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11
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Case AJ, Bhavani S, Macharia G, Pretorius Z, Coetzee V, Kloppers F, Tyagi P, Brown-Guedira G, Steffenson BJ. Mapping adult plant stem rust resistance in barley accessions Hietpas-5 and GAW-79. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2018; 131:2245-2266. [PMID: 30109391 DOI: 10.1007/s00122-018-3149-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
Key message Major stem rust resistance QTLs proposed to be Rpg2 from Hietpas-5 and Rpg3 from GAW-79 were identified in chromosomes 2H and 5H, respectively, and will enhance the diversity of stem rust resistance in barley improvement programs. Stem rust is a devastating disease of cereal crops worldwide. In barley (Hordeum vulgare ssp. vulgare), the disease is caused by two pathogens: Puccinia graminis f. sp. secalis (Pgs) and Puccinia graminis f. sp. tritici (Pgt). In North America, the stem rust resistance gene Rpg1 has protected barley from serious losses for more than 60 years; however, widely virulent Pgt races from Africa in the Ug99 group threaten the crop. The accessions Hietpas-5 (CIho 7124) and GAW-79 (PI 382313) both possess moderate-to-high levels of adult plant resistance to stem rust and are the sources of the resistance genes Rpg2 and Rpg3, respectively. To identify quantitative trait loci (QTL) for stem rust resistance in Hietpas-5 and GAW-79, two biparental populations were developed with Hiproly (PI 60693), a stem rust-susceptible accession. Both populations were phenotyped to the North American Pgt races of MCCFC, QCCJB, and HKHJC in St. Paul, Minnesota, and to African Pgt races (predominately TTKSK in the Ug99 group) in Njoro, Kenya. In the Hietpas-5/Hiproly population, a major effect QTL was identified in chromosome 2H, which is proposed as the location for Rpg2. In the GAW-79/Hiproly population, a major effect QTL was identified in chromosome 5H and is the proposed location for Rpg3. These QTLs will enhance the diversity of stem rust resistance in barley improvement programs.
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Affiliation(s)
- Austin J Case
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
| | - Sridhar Bhavani
- Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT), Nairobi, Kenya
| | - Godwin Macharia
- Kenya Agriculture and Livestock Research Organization (KALRO), Njoro, Kenya
| | - Zacharias Pretorius
- Department of Plant Sciences, University of the Free State, Bloemfontein, Republic of South Africa
| | - Vicky Coetzee
- Pannar Seed (Pyt) Ltd, Greytown, Republic of South Africa
| | | | - Priyanka Tyagi
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, 27695, USA
| | | | - Brian J Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA.
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Case AJ, Bhavani S, Macharia G, Steffenson BJ. Genome-wide association study of stem rust resistance in a world collection of cultivated barley. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2018; 131:107-126. [PMID: 29177535 DOI: 10.1007/s00122-017-2989-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/19/2017] [Indexed: 05/20/2023]
Abstract
QTL conferring a 14-40% reduction in adult plant stem rust severity to multiple races of Pgt were found on chromosome 5H and will be useful in barley breeding. Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt) is an important disease of barley. The resistance gene Rpg1 has protected the crop against stem rust losses for over 70 years in North America, but is not effective against the African Pgt race TTKSK (and its variants) nor the domestic race QCCJB. To identify resistance to these Rpg1-virulent races, the Barley iCore Collection, held by the United States Department of Agriculture-Agricultural Research Service National Small Grains Collection was evaluated for adult plant resistance (APR) and seedling resistance to race TTKSK and APR to race QCCJB and the Pgt TTKSK composite of races TTKSK, TTKST, TTKTK, and TTKTT. Using a genome-wide association study approach based on 6224 single nucleotide polymorphic markers, seven significant loci for stem rust resistance were identified on chromosomes 1H, 2H, 3H, and 5H. The most significant markers detected were 11_11355 and SCRI_RS_177017 at 71-75 cM on chromosome 5H, conferring APR to QCCJB and TTKSK composite. Significant markers were also detected for TTKSK seedling resistance on chromosome 5H. All markers detected on 5H were independent of the rpg4/Rpg5 complex at 152-168 cM. This study verified the importance of the 11_11355 locus in conferring APR to races QCCJB and TTKSK and suggests that it may be effective against other races in the Ug99 lineage.
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Affiliation(s)
- Austin J Case
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
| | - Sridhar Bhavani
- Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT), Nairobi, Kenya
| | - Godwin Macharia
- Kenya Agriculture Livestock Research Organization (KALRO), Njoro, Kenya
| | - Brian J Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA.
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Samad‐Zamini M, Schweiger W, Nussbaumer T, Mayer KF, Buerstmayr H. Time-course expression QTL-atlas of the global transcriptional response of wheat to Fusarium graminearum. PLANT BIOTECHNOLOGY JOURNAL 2017; 15:1453-1464. [PMID: 28332274 PMCID: PMC5633761 DOI: 10.1111/pbi.12729] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 01/11/2017] [Accepted: 03/16/2017] [Indexed: 05/09/2023]
Abstract
Fusarium head blight is a devastating disease of small grain cereals such as bread wheat (Triticum aestivum). The pathogen switches from a biotrophic to a nectrotrophic lifestyle in course of disease development forcing its host to adapt its defence strategies. Using a genetical genomics approach, we illustrate genome-wide reconfigurations of genetic control over transcript abundances between two decisive time points after inoculation with the causative pathogen Fusarium graminearum. Whole transcriptome measurements have been recorded for 163 lines of a wheat doubled haploid population segregating for several resistance genes yielding 15 552 at 30 h and 15 888 eQTL at 50 h after inoculation. The genetic map saturated with transcript abundance-derived markers identified of a novel QTL on chromosome 6A, besides the previously reported QTL Fhb1 and Qfhs.ifa-5A. We find a highly different distribution of eQTL between time points with about 40% of eQTL being unique for the respective assessed time points. But also for more than 20% of genes governed by eQTL at either time point, genetic control changes in time. These changes are reflected in the dynamic compositions of three major regulatory hotspots on chromosomes 2B, 4A and 5A. In particular, control of defence-related biological mechanisms concentrated in the hotspot at 4A shift to hotspot 2B as the disease progresses. Hotspots do not colocalize with phenotypic QTL, and within their intervals no higher than expected number of eQTL was detected. Thus, resistance conferred by either QTL is mediated by few or single genes.
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Affiliation(s)
- Mina Samad‐Zamini
- Institute for Biotechnology in Plant Production (IFA‐Tulln)BOKU ‐ University of Natural Resources and Life SciencesTullnAustria
| | - Wolfgang Schweiger
- Institute for Biotechnology in Plant Production (IFA‐Tulln)BOKU ‐ University of Natural Resources and Life SciencesTullnAustria
- Present address:
BIOMIN Research CenterTulln3430Austria
| | - Thomas Nussbaumer
- Plant Genome and Systems BiologyHelmholtz Zentrum MünchenNeuherbergGermany
- Present address:
Division of Computational System BiologyDepartment of Microbiology and Ecosystem ScienceUniversity of ViennaVienna1090Austria
| | - Klaus F.X. Mayer
- Plant Genome and Systems BiologyHelmholtz Zentrum MünchenNeuherbergGermany
| | - Hermann Buerstmayr
- Institute for Biotechnology in Plant Production (IFA‐Tulln)BOKU ‐ University of Natural Resources and Life SciencesTullnAustria
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14
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Sallam AH, Tyagi P, Brown-Guedira G, Muehlbauer GJ, Hulse A, Steffenson BJ. Genome-Wide Association Mapping of Stem Rust Resistance in Hordeum vulgare subsp. spontaneum. G3 (BETHESDA, MD.) 2017; 7:3491-3507. [PMID: 28855281 PMCID: PMC5633397 DOI: 10.1534/g3.117.300222] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 08/24/2017] [Indexed: 01/06/2023]
Abstract
Stem rust was one of the most devastating diseases of barley in North America. Through the deployment of cultivars with the resistance gene Rpg1, losses to stem rust have been minimal over the past 70 yr. However, there exist both domestic (QCCJB) and foreign (TTKSK aka isolate Ug99) pathotypes with virulence for this important gene. To identify new sources of stem rust resistance for barley, we evaluated the Wild Barley Diversity Collection (WBDC) (314 ecogeographically diverse accessions of Hordeum vulgare subsp. spontaneum) for seedling resistance to four pathotypes (TTKSK, QCCJB, MCCFC, and HKHJC) of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici, Pgt) and one isolate (92-MN-90) of the rye stem rust pathogen (P. graminis f. sp. secalis, Pgs). Based on a coefficient of infection, the frequency of resistance in the WBDC was low ranging from 0.6% with HKHJC to 19.4% with 92-MN-90. None of the accessions was resistant to all five cultures of P. graminis A genome-wide association study (GWAS) was conducted to map stem rust resistance loci using 50,842 single-nucleotide polymorphic markers generated by genotype-by-sequencing and ordered using the new barley reference genome assembly. After proper accounting for genetic relatedness and structure among accessions, 45 quantitative trait loci were identified for resistance to P. graminis across all seven barley chromosomes. Three novel loci associated with resistance to TTKSK, QCCJB, MCCFC, and 92-MN-90 were identified on chromosomes 5H and 7H, and two novel loci associated with resistance to HKHJC were identified on chromosomes 1H and 3H. These novel alleles will enhance the diversity of resistance available for cultivated barley.
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Affiliation(s)
- Ahmad H Sallam
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota 55108
| | - Priyanka Tyagi
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina 27695
| | - Gina Brown-Guedira
- United States Department of Agriculture-Agricultural Research Service, Raleigh, North Carolina 27695
| | - Gary J Muehlbauer
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108
| | - Alex Hulse
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota 55108
| | - Brian J Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota 55108
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15
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Interchromosomal Transfer of Immune Regulation During Infection of Barley with the Powdery Mildew Pathogen. G3-GENES GENOMES GENETICS 2017; 7:3317-3329. [PMID: 28790145 PMCID: PMC5633382 DOI: 10.1534/g3.117.300125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Powdery mildew pathogens colonize over 9500 plant species, causing critical yield loss. The Ascomycete fungus, Blumeria graminis f. sp. hordei (Bgh), causes powdery mildew disease in barley (Hordeum vulgare L.). Successful infection begins with penetration of host epidermal cells, culminating in haustorial feeding structures, facilitating delivery of fungal effectors to the plant and exchange of nutrients from host to pathogen. We used expression Quantitative Trait Locus (eQTL) analysis to dissect the temporal control of immunity-associated gene expression in a doubled haploid barley population challenged with Bgh. Two highly significant regions possessing trans eQTL were identified near the telomeric ends of chromosomes (Chr) 2HL and 1HS. Within these regions reside diverse resistance loci derived from barley landrace H. laevigatum (MlLa) and H. vulgare cv. Algerian (Mla1), which associate with the altered expression of 961 and 3296 genes during fungal penetration of the host and haustorial development, respectively. Regulatory control of transcript levels for 299 of the 961 genes is reprioritized from MlLa on 2HL to Mla1 on 1HS as infection progresses, with 292 of the 299 alternating the allele responsible for higher expression, including Adaptin Protein-2 subunit μ AP2M and Vesicle Associated Membrane Protein VAMP72 subfamily members VAMP721/722. AP2M mediates effector-triggered immunity (ETI) via endocytosis of plasma membrane receptor components. VAMP721/722 and SNAP33 form a Soluble N-ethylmaleimide-sensitive factor Attachment Protein REceptor (SNARE) complex with SYP121 (PEN1), which is engaged in pathogen associated molecular pattern (PAMP)-triggered immunity via exocytosis. We postulate that genes regulated by alternate chromosomal positions are repurposed as part of a conserved immune complex to respond to different pathogen attack scenarios.
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16
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Corwin JA, Kliebenstein DJ. Quantitative Resistance: More Than Just Perception of a Pathogen. THE PLANT CELL 2017; 29:655-665. [PMID: 28302676 PMCID: PMC5435431 DOI: 10.1105/tpc.16.00915] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/26/2017] [Accepted: 03/16/2017] [Indexed: 05/20/2023]
Abstract
Molecular plant pathology has focused on studying large-effect qualitative resistance loci that predominantly function in detecting pathogens and/or transmitting signals resulting from pathogen detection. By contrast, less is known about quantitative resistance loci, particularly the molecular mechanisms controlling variation in quantitative resistance. Recent studies have provided insight into these mechanisms, showing that genetic variation at hundreds of causal genes may underpin quantitative resistance. Loci controlling quantitative resistance contain some of the same causal genes that mediate qualitative resistance, but the predominant mechanisms of quantitative resistance extend beyond pathogen recognition. Indeed, most causal genes for quantitative resistance encode specific defense-related outputs such as strengthening of the cell wall or defense compound biosynthesis. Extending previous work on qualitative resistance to focus on the mechanisms of quantitative resistance, such as the link between perception of microbe-associated molecular patterns and growth, has shown that the mechanisms underlying these defense outputs are also highly polygenic. Studies that include genetic variation in the pathogen have begun to highlight a potential need to rethink how the field considers broad-spectrum resistance and how it is affected by genetic variation within pathogen species and between pathogen species. These studies are broadening our understanding of quantitative resistance and highlighting the potentially vast scale of the genetic basis of quantitative resistance.
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Affiliation(s)
- Jason A Corwin
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Daniel J Kliebenstein
- Department of Plant Sciences, University of California, Davis, California 95616
- DynaMo Center of Excellence, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
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17
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Christie N, Myburg AA, Joubert F, Murray SL, Carstens M, Lin YC, Meyer J, Crampton BG, Christensen SA, Ntuli JF, Wighard SS, Van de Peer Y, Berger DK. Systems genetics reveals a transcriptional network associated with susceptibility in the maize-grey leaf spot pathosystem. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:746-763. [PMID: 27862526 DOI: 10.1111/tpj.13419] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 10/20/2016] [Accepted: 11/04/2016] [Indexed: 05/20/2023]
Abstract
We used a systems genetics approach to elucidate the molecular mechanisms of the responses of maize to grey leaf spot (GLS) disease caused by Cercospora zeina, a threat to maize production globally. Expression analysis of earleaf samples in a subtropical maize recombinant inbred line population (CML444 × SC Malawi) subjected in the field to C. zeina infection allowed detection of 20 206 expression quantitative trait loci (eQTLs). Four trans-eQTL hotspots coincided with GLS disease QTLs mapped in the same field experiment. Co-expression network analysis identified three expression modules correlated with GLS disease scores. The module (GY-s) most highly correlated with susceptibility (r = 0.71; 179 genes) was enriched for the glyoxylate pathway, lipid metabolism, diterpenoid biosynthesis and responses to pathogen molecules such as chitin. The GY-s module was enriched for genes with trans-eQTLs in hotspots on chromosomes 9 and 10, which also coincided with phenotypic QTLs for susceptibility to GLS. This transcriptional network has significant overlap with the GLS susceptibility response of maize line B73, and may reflect pathogen manipulation for nutrient acquisition and/or unsuccessful defence responses, such as kauralexin production by the diterpenoid biosynthesis pathway. The co-expression module that correlated best with resistance (TQ-r; 1498 genes) was enriched for genes with trans-eQTLs in hotspots coinciding with GLS resistance QTLs on chromosome 9. Jasmonate responses were implicated in resistance to GLS through co-expression of COI1 and enrichment of genes with the Gene Ontology term 'cullin-RING ubiquitin ligase complex' in the TQ-r module. Consistent with this, JAZ repressor expression was highly correlated with the severity of GLS disease in the GY-s susceptibility network.
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Affiliation(s)
- Nanette Christie
- Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
- Centre for Bioinformatics and Computational Biology, Genomics Research Institute, Department of Biochemistry, University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Alexander A Myburg
- Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Fourie Joubert
- Centre for Bioinformatics and Computational Biology, Genomics Research Institute, Department of Biochemistry, University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Shane L Murray
- Centre for Proteomic and Genomic Research, 0A Anzio Rd, Observatory, Cape Town, 7925, South Africa
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa
| | - Maryke Carstens
- Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Yao-Cheng Lin
- Department of Plant Systems Biology, VIB, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Jacqueline Meyer
- Centre for Proteomic and Genomic Research, 0A Anzio Rd, Observatory, Cape Town, 7925, South Africa
- Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Bridget G Crampton
- Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Shawn A Christensen
- Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Chemistry Research Unit, Gainesville, FL, 32608, USA
| | - Jean F Ntuli
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa
| | - Sara S Wighard
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa
| | - Yves Van de Peer
- Department of Plant Systems Biology, VIB, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
- Department of Genetics, Genomics Research Institute, University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
| | - Dave K Berger
- Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), Genomics Research Institute (GRI), University of Pretoria, Private Bag X20, Pretoria, 0028, South Africa
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18
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Wang Y, Richard R, Pan Y. Prior knowledge guided eQTL mapping for identifying candidate genes. BMC Bioinformatics 2016; 17:531. [PMID: 27964730 PMCID: PMC5155383 DOI: 10.1186/s12859-016-1387-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 11/26/2016] [Indexed: 12/03/2022] Open
Abstract
Background Expression quantitative trait loci (eQTL) mapping is often used to identify genetic loci and candidate genes correlated with traits. Although usually a group of genes affect complex traits, genes in most eQTL mapping methods are considered as independent. Recently, some eQTL mapping methods have accounted for correlated genes, used biological prior knowledge and applied these in model species such as yeast or mouse. However, biological prior knowledge might be very limited for most species. Results We proposed a data-driven prior knowledge guided eQTL mapping for identifying candidate genes. At first, quantitative trait loci (QTL) analysis was used to identify single nucleotide polymorphisms (SNP) markers that are associated with traits. Then co-expressed gene modules were generated and gene modules significantly associated with traits were selected. Prior knowledge from QTL mapping was used for eQTL mapping on the selected modules. We tested and compared prior knowledge guided eQTL mapping to the eQTL mapping with no prior knowledge in a simulation study and two barley stem rust resistance case studies. The results in simulation study and real barley case studies show that models using prior knowledge outperform models without prior knowledge. In the first case study, three gene modules were selected and one of the gene modules was enriched with defense response Gene Ontology (GO) terms. Also, one probe in the gene module is mapped to Rpg1, previously identified as resistance gene to stem rust. In the second case study, four gene modules are identified, one gene module is significantly enriched with defense response to fungus and bacterium. Conclusions Prior knowledge guided eQTL mapping is an effective method for identifying candidate genes. The case studies in stem rust show that this approach is robust, and outperforms methods with no prior knowledge in identifying candidate genes. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1387-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yunli Wang
- National Research Council Canada, 1200 Montreal Rd., Ottawa, K1A 0R6, Canada.
| | - Rene Richard
- National Research Council Canada, 46 Dineen Dr., Fredericton, E3B 9W4, Canada
| | - Youlian Pan
- National Research Council Canada, 1200 Montreal Rd., Ottawa, K1A 0R6, Canada
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19
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Andolfo G, Iovieno P, Frusciante L, Ercolano MR. Genome-Editing Technologies for Enhancing Plant Disease Resistance. FRONTIERS IN PLANT SCIENCE 2016; 7:1813. [PMID: 27990151 PMCID: PMC5130979 DOI: 10.3389/fpls.2016.01813] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/16/2016] [Indexed: 05/23/2023]
Abstract
One of the greatest challenges for agricultural science in the 21st century is to improve yield stability through the progressive development of superior cultivars. The increasing numbers of infectious plant diseases that are caused by plant-pathogens make it ever more necessary to develop new strategies for plant disease resistance breeding. Targeted genome engineering allows the introduction of precise modifications directly into a commercial variety, offering a viable alternative to traditional breeding methods. Genome editing is a powerful tool for modifying crucial players in the plant immunity system. In this work, we propose and discuss genome-editing strategies and targets for improving resistance to phytopathogens. First of all, we present the opportunities to rewrite the effector-target sequence for avoiding effector-target molecular interaction and also to modify effector-target promoters for increasing the expression of target genes involved in the resistance process. In addition, we describe potential approaches for obtaining synthetic R-genes through genome-editing technologies (GETs). Finally, we illustrate a genome editing flowchart to modify the pathogen recognition sites and engineer an R-gene that mounts resistance to some phylogenetically divergent pathogens. GETs potentially mark the beginning of a new era, in which synthetic biology affords a basis for obtaining a reinforced plant defense system. Nowadays it is conceivable that by modulating the function of the major plant immunity players, we will be able to improve crop performance for a sustainable agriculture.
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Affiliation(s)
| | | | | | - Maria R. Ercolano
- Department of Agricultural Sciences, University of Naples ‘Federico II’Portici, Italy
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Verta JP, Landry CR, MacKay J. Dissection of expression-quantitative trait locus and allele specificity using a haploid/diploid plant system - insights into compensatory evolution of transcriptional regulation within populations. THE NEW PHYTOLOGIST 2016; 211:159-171. [PMID: 26891783 DOI: 10.1111/nph.13888] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 01/06/2016] [Indexed: 06/05/2023]
Abstract
Regulation of gene expression plays a central role in translating genotypic variation into phenotypic variation. Dissection of the genetic basis of expression variation is key to understanding how expression regulation evolves. Such analyses remain challenging in contexts where organisms are outbreeding, highly heterozygous and long-lived such as in the case of conifer trees. We developed an RNA sequencing (RNA-seq)-based approach for both expression-quantitative trait locus (eQTL) mapping and the detection of cis-acting (allele-specific) vs trans-acting (non-allele-specific) eQTLs. This method can be potentially applied to many conifers. We used haploid and diploid meiotic seed tissues of a single self-fertilized white spruce (Picea glauca) individual to dissect eQTLs according to linkage and allele specificity. The genetic architecture of local eQTLs linked to the expressed genes was particularly complex, consisting of cis-acting, trans-acting and, surprisingly, compensatory cis-trans effects. These compensatory effects influence expression in opposite directions and are neutral when combined in homozygotes. Nearly half of local eQTLs were under compensation, indicating that close linkage between compensatory cis-trans factors is common in spruce. Compensated genes were overrepresented in developmental and cell organization functions. Our haploid-diploid eQTL analysis in spruce revealed that compensatory cis-trans eQTLs segregate within populations and evolve in close genetic linkage.
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Affiliation(s)
- Jukka-Pekka Verta
- Centre d'étude de la forêt, Département des sciences du bois et de la forêt, Université Laval, Québec, QC, Canada G1V 0A6
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada G1V 0A6
| | - Christian R Landry
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada G1V 0A6
- Département de Biologie, Université Laval, Québec, QC, Canada G1V 0A6
| | - John MacKay
- Centre d'étude de la forêt, Département des sciences du bois et de la forêt, Université Laval, Québec, QC, Canada G1V 0A6
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada G1V 0A6
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
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Dawson AM, Ferguson JN, Gardiner M, Green P, Hubbard A, Moscou MJ. Isolation and fine mapping of Rps6: an intermediate host resistance gene in barley to wheat stripe rust. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2016; 129:831-843. [PMID: 26754419 PMCID: PMC4799244 DOI: 10.1007/s00122-015-2659-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/14/2015] [Indexed: 05/24/2023]
Abstract
We uncouple host and nonhost resistance in barley to Puccinia striiformis ff. spp. hordei and tritici . We isolate, fine map, and physically anchor Rps6 to chromosome 7H in barley. A plant may be considered a nonhost of a pathogen if all known genotypes of a plant species are resistant to all known isolates of a pathogen species. However, if a small number of genotypes are susceptible to some known isolates of a pathogen species this plant may be considered an intermediate host. Barley (Hordeum vulgare) is an intermediate host for Puccinia striiformis f. sp. tritici (Pst), the causal agent of wheat stripe rust. We wanted to understand the genetic architecture underlying resistance to Pst and to determine whether any overlap exists with resistance to the host pathogen, Puccinia striiformis f. sp. hordei (Psh). We mapped Pst resistance to chromosome 7H and show that host and intermediate host resistance is genetically uncoupled. Therefore, we designate this resistance locus Rps6. We used phenotypic and genotypic selection on F2:3 families to isolate Rps6 and fine mapped the locus to a 0.1 cM region. Anchoring of the Rps6 locus to the barley physical map placed the region on a single fingerprinted contig spanning a physical region of 267 kb. Efforts are now underway to sequence the minimal tiling path and to delimit the physical region harboring Rps6. This will facilitate additional marker development and permit identification of candidate genes in the region.
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Affiliation(s)
- Andrew M Dawson
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - John N Ferguson
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
- School of Biological Sciences, University of Essex, Colchester, CO4 3SQ, UK
| | - Matthew Gardiner
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Phon Green
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Amelia Hubbard
- National Institute of Agricultural Botany, Huntingdon Road, Cambridge, CB3 0LE, UK
| | - Matthew J Moscou
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK.
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Parrott DL, Huang L, Fischer AM. Downregulation of a barley (Hordeum vulgare) leucine-rich repeat, non-arginine-aspartate receptor-like protein kinase reduces expression of numerous genes involved in plant pathogen defense. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 100:130-140. [PMID: 26820571 DOI: 10.1016/j.plaphy.2016.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 01/12/2016] [Indexed: 05/24/2023]
Abstract
Pattern recognition receptors represent a first line of plant defense against pathogens. Comparing the flag leaf transcriptomes of barley (Hordeum vulgare L.) near-isogenic lines varying in the allelic state of a locus controlling senescence, we have previously identified a leucine-rich repeat receptor-like protein kinase gene (LRR-RLK; GenBank accession: AK249842), which was strongly upregulated in leaves of early-as compared to late-senescing germplasm. Bioinformatic analysis indicated that this gene codes for a subfamily XII, non-arginine-aspartate (non-RD) LRR-RLK. Virus-induced gene silencing resulted in a two-fold reduction of transcript levels as compared to controls. Transcriptomic comparison of leaves from untreated plants, from plants treated with virus only without any plant sequences (referred to as 'empty virus' control), and from plants in which AK249842 expression was knocked down identified numerous genes involved in pathogen defense. These genes were strongly induced in 'empty virus' as compared to untreated controls, but their expression was significantly reduced (again compared to 'empty virus' controls) when AK249842 was knocked down, indicating that their expression partially depends on the LRR-RLK investigated here. Expression analysis, using datasets from BarleyBase/PLEXdb, demonstrated that AK249842 transcript levels are heavily influenced by the allelic state of the well-characterized mildew resistance a (Mla) locus, and that the gene is induced after powdery mildew and stem rust infection. Together, our data suggest that AK249842 is a barley pattern recognition receptor with a tentative role in defense against fungal pathogens, setting the stage for its full functional characterization.
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Affiliation(s)
- David L Parrott
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA
| | - Li Huang
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA
| | - Andreas M Fischer
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA.
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Corwin JA, Copeland D, Feusier J, Subedy A, Eshbaugh R, Palmer C, Maloof J, Kliebenstein DJ. The Quantitative Basis of the Arabidopsis Innate Immune System to Endemic Pathogens Depends on Pathogen Genetics. PLoS Genet 2016; 12:e1005789. [PMID: 26866607 PMCID: PMC4750985 DOI: 10.1371/journal.pgen.1005789] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 12/16/2015] [Indexed: 01/19/2023] Open
Abstract
The most established model of the eukaryotic innate immune system is derived from examples of large effect monogenic quantitative resistance to pathogens. However, many host-pathogen interactions involve many genes of small to medium effect and exhibit quantitative resistance. We used the Arabidopsis-Botrytis pathosystem to explore the quantitative genetic architecture underlying host innate immune system in a population of Arabidopsis thaliana. By infecting a diverse panel of Arabidopsis accessions with four phenotypically and genotypically distinct isolates of the fungal necrotroph B. cinerea, we identified a total of 2,982 genes associated with quantitative resistance using lesion area and 3,354 genes associated with camalexin production as measures of the interaction. Most genes were associated with resistance to a specific Botrytis isolate, which demonstrates the influence of pathogen genetic variation in analyzing host quantitative resistance. While known resistance genes, such as receptor-like kinases (RLKs) and nucleotide-binding site leucine-rich repeat proteins (NLRs), were found to be enriched among associated genes, they only account for a small fraction of the total genes associated with quantitative resistance. Using publically available co-expression data, we condensed the quantitative resistance associated genes into co-expressed gene networks. GO analysis of these networks implicated several biological processes commonly connected to disease resistance, including defense hormone signaling and ROS production, as well as novel processes, such as leaf development. Validation of single gene T-DNA knockouts in a Col-0 background demonstrate a high success rate (60%) when accounting for differences in environmental and Botrytis genetic variation. This study shows that the genetic architecture underlying host innate immune system is extremely complex and is likely able to sense and respond to differential virulence among pathogen genotypes.
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Affiliation(s)
- Jason A. Corwin
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California - Davis, Davis, California, United States of America
| | - Daniel Copeland
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California - Davis, Davis, California, United States of America
| | - Julie Feusier
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California - Davis, Davis, California, United States of America
| | - Anushriya Subedy
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California - Davis, Davis, California, United States of America
| | - Robert Eshbaugh
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California - Davis, Davis, California, United States of America
| | - Christine Palmer
- Department of Plant Biology, College of Biological Sciences, University of California - Davis, Davis, California, United States of America
| | - Julin Maloof
- Department of Plant Biology, College of Biological Sciences, University of California - Davis, Davis, California, United States of America
| | - Daniel J. Kliebenstein
- Department of Plant Sciences, College of Agricultural and Environmental Sciences, University of California - Davis, Davis, California, United States of America
- DynaMo Center of Excellence, University of Copenhagen, Frederiksberg, Denmark
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24
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Turuspekov Y, Ormanbekova D, Rsaliev A, Abugalieva S. Genome-wide association study on stem rust resistance in Kazakh spring barley lines. BMC PLANT BIOLOGY 2016; 16 Suppl 1:6. [PMID: 26821649 PMCID: PMC4895317 DOI: 10.1186/s12870-015-0686-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
BACKGROUND Stem rust (SR) is one of the most economically devastating barley diseases in Kazakhstan, and in some years it causes up to 50 % of yield losses. Routine conventional breeding for resistance to stem rust is almost always in progress in all Kazakhstan breeding stations. However, molecular marker based approach towards new SR resistance genes identification and relevant marker-assisted selection had never been employed in Kazakhstan yet. In this study, as a preliminary step the GWAS (genome-wide association study) mapping was applied in attempt to identify reliable SNP markers and quantitative trait loci (QTL) associated with resistance to SR. RESULTS Barley collection of 92 commercial cultivars and promising lines was genotyped using a high-throughput single nucleotide polymorphism (9,000 SNP) Illumina iSelect array. 6,970 SNPs out of 9,000 total were polymorphic and scorable. 5,050 SNPs out of 6,970 passed filtering threshold and were used for association mapping (AM). All 92 accessions were phenotyped for resistance to SR by observing adult plants in artificially infected plots at the Research Institute for Biological Safety Problems in Dzhambul region of Kazakhstan. GLM analysis allowed the identification of 15 SNPs associated with the resistance at the heading time (HA) phase, and 2 SNPs at the seed's milky-waxy maturity (SM) phase. However, after application of 5 % Bonferroni multiple test correction, only 2 SNPs at the HA stage on the same position of chromosome 6H can be claimed as reliable markers for SR resistance. The MLM analysis after the Bonferroni correction did not reveal any associations in this study, although distribution lines in the quantile-quantile (QQ) plot indicates that overcorrection in the test due to both Q and K matrices usage. CONCLUSIONS Obtained data suggest that genome wide genotyping of 92 spring barley accessions from Kazakhstan with 9 K Illumina SNP array was highly efficient. Linkage disequilibrium based mapping approach allowed the identification of highly significant QTL for the SR resistance at the HA phase of growth on chromosome 6H. On the other hand, no significant QTL was detected at the SM phase, assuming that for a successful GWASmapping experiment a larger size population with more diverse genetic background should be tested. Obtained results provide additional information towards better understanding of SR resistance in barley.
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Affiliation(s)
| | | | - Aralbek Rsaliev
- Research Institute for Biological Safety Problems, Gvardeiskiy vil, Dzhambul region, Kazakhstan.
| | - Saule Abugalieva
- Institute of Plant Biology and Biotechnology, Almaty, Kazakhstan.
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25
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Survival Rate and Transcriptional Response upon Infection with the Generalist Parasite Beauveria bassiana in a World-Wide Sample of Drosophila melanogaster. PLoS One 2015; 10:e0132129. [PMID: 26154519 PMCID: PMC4495925 DOI: 10.1371/journal.pone.0132129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 06/10/2015] [Indexed: 01/22/2023] Open
Abstract
The ability to cope with infection by a parasite is one of the major challenges for any host species and is a major driver of evolution. Parasite pressure differs between habitats. It is thought to be higher in tropical regions compared to temporal ones. We infected Drosophila melanogaster from two tropical (Malaysia and Zimbabwe) and two temperate populations (the Netherlands and North Carolina) with the generalist entomopathogenic fungus Beauveria bassiana to examine if adaptation to local parasite pressures led to differences in resistance. Contrary to previous findings we observed increased survival in temperate populations. This, however, is not due to increased resistance to infection per se, but rather the consequence of a higher general vigor of the temperate populations. We also assessed transcriptional response to infection within these flies eight and 24 hours after infection. Only few genes were induced at the earlier time point, most of which are involved in detoxification. In contrast, we identified more than 4,000 genes that changed their expression state after 24 hours. This response was generally conserved over all populations with only few genes being uniquely regulated in the temperate populations. We furthermore found that the American population was transcriptionally highly diverged from all other populations concerning basal levels of gene expression. This was particularly true for stress and immune response genes, which might be the genetic basis for their elevated vigor.
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26
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Zurn JD, Dugyala S, Borowicz P, Brueggeman R, Acevedo M. Unraveling the Wheat Stem Rust Infection Process on Barley Genotypes Through Relative qPCR and Fluorescence Microscopy. PHYTOPATHOLOGY 2015; 105:707-712. [PMID: 25689517 DOI: 10.1094/phyto-09-14-0251-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The infection process of wheat stem rust (Puccinia graminis f. sp. tritici) on barley (Hordeum vulgare) is often observed as a mesothetic infection type at the seedling stages, and cultivars containing the same major resistance genes often show variation in the level of resistance provided against the same pathogen race or isolate. Thus, robust phenotyping data based on quantification of fungal DNA can improve the ability to elucidate host-pathogen interaction, especially at early time points of infection when disease symptoms are not yet evident. Quantitative real-time polymerase chain reaction (qPCR) was used to determine the amount of fungal DNA relative to host DNA in infected tissue, providing new insights about fungal development and host resistance during the infection process in this pathosystem. The stem rust susceptible 'Steptoe', resistant cultivars containing only Rpg1 ('Beacon', 'Morex', and 'Chevron'), and the resistant line Q21861 containing Rpg1 and the rpg4/Rpg5 complex were evaluated using the traditional 0-to-4 rating scale, fluorescence microscopy, and qPCR. Statistical differences (P<0.05) were observed in fungal development as early as 24 h postinoculation using the qPCR assay. Fungal development observed using fluorescence microscopy displayed the same hierarchal ordering observed using the qPCR assay. The fungal development occurring at 24 and 48 h postinoculation was vastly different than what was expected using the traditional disease phenotyping methodology; with Steptoe appearing more resistant than the barley lines harboring the known Rpg1 and rpg4/Rpg5 resistance complex. These data indicate potential early prehaustorial resistance contributions in a cultivar considered susceptible based on infection type. Moreover, the temporal differences in resistance suggest pre- and post-haustorial resistance mechanisms in the barley-wheat stem rust infection process, indicating potential host genotype contributions related to basal defense during the wheat stem rust infection process.
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Affiliation(s)
- J D Zurn
- First, second, fourth, and fifth authors: Department of Plant Pathology, and third author: Department of Animal Sciences, North Dakota State University, Fargo 58108
| | - S Dugyala
- First, second, fourth, and fifth authors: Department of Plant Pathology, and third author: Department of Animal Sciences, North Dakota State University, Fargo 58108
| | - P Borowicz
- First, second, fourth, and fifth authors: Department of Plant Pathology, and third author: Department of Animal Sciences, North Dakota State University, Fargo 58108
| | - R Brueggeman
- First, second, fourth, and fifth authors: Department of Plant Pathology, and third author: Department of Animal Sciences, North Dakota State University, Fargo 58108
| | - M Acevedo
- First, second, fourth, and fifth authors: Department of Plant Pathology, and third author: Department of Animal Sciences, North Dakota State University, Fargo 58108
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27
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Gill US, Lee S, Mysore KS. Host versus nonhost resistance: distinct wars with similar arsenals. PHYTOPATHOLOGY 2015; 105:580-7. [PMID: 25626072 DOI: 10.1094/phyto-11-14-0298-rvw] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plants face several challenges by bacterial, fungal, oomycete, and viral pathogens during their life cycle. In order to defend against these biotic stresses, plants possess a dynamic, innate, natural immune system that efficiently detects potential pathogens and initiates a resistance response in the form of basal resistance and/or resistance (R)-gene-mediated defense, which is often associated with a hypersensitive response. Depending upon the nature of plant-pathogen interactions, plants generally have two main defense mechanisms, host resistance and nonhost resistance. Host resistance is generally controlled by single R genes and less durable compared with nonhost resistance. In contrast, nonhost resistance is believed to be a multi-gene trait and more durable. In this review, we describe the mechanisms of host and nonhost resistance against fungal and bacterial plant pathogens. In addition, we also attempt to compare host and nonhost resistance responses to identify similarities and differences, and their practical applications in crop improvement.
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Affiliation(s)
- Upinder S Gill
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401
| | - Seonghee Lee
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401
| | - Kirankumar S Mysore
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401
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28
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Wang Y, Han Y, Teng W, Zhao X, Li Y, Wu L, Li D, Li W. Expression quantitative trait loci infer the regulation of isoflavone accumulation in soybean (Glycine max L. Merr.) seed. BMC Genomics 2014; 15:680. [PMID: 25124843 PMCID: PMC4138391 DOI: 10.1186/1471-2164-15-680] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 07/30/2014] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mapping expression quantitative trait loci (eQTL) of targeted genes represents a powerful and widely adopted approach to identify putative regulatory variants. Linking regulation differences to specific genes might assist in the identification of networks and interactions. The objective of this study is to identify eQTL underlying expression of four gene families encoding isoflavone synthetic enzymes involved in the phenylpropanoid pathway, which are phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), chalcone synthase (CHS; EC 2.3.1.74), 2-hydroxyisoflavanone synthase (IFS; EC1.14.13.136) and flavanone 3-hydroxylase (F3H; EC 1.14.11.9). A population of 130 recombinant inbred lines (F5:11), derived from a cross between soybean cultivar 'Zhongdou 27' (high isoflavone) and 'Jiunong 20' (low isoflavone), and a total of 194 simple sequence repeat (SSR) markers were used in this study. Overlapped loci of eQTLs and phenotypic QTLs (pQTLs) were analyzed to identify the potential candidate genes underlying the accumulation of isoflavone in soybean seed. RESULTS Thirty three eQTLs (thirteen cis-eQTLs and twenty trans-eQTLs) underlying the transcript abundance of the four gene families were identified on fifteen chromosomes. The eQTLs between Satt278-Sat_134, Sat_134-Sct_010 and Satt149-Sat_234 underlie the expression of both IFS and CHS genes. Five eQTL intervals were overlapped with pQTLs. A total of eleven candidate genes within the overlapped eQTL and pQTL were identified. CONCLUSIONS These results will be useful for the development of marker-assisted selection to breed soybean cultivars with high or low isoflavone contents and for map-based cloning of new isoflavone related genes.
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Affiliation(s)
- Yan Wang
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
| | - Yingpeng Han
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
| | - Weili Teng
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
| | - Xue Zhao
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
| | - Yongguang Li
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
| | - Lin Wu
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
| | - Dongmei Li
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
| | - Wenbin Li
- Key Laboratory of Soybean Biology in Chinese Ministry of Education (key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030 China
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Graham NS, Hammond JP, Lysenko A, Mayes S, O Lochlainn S, Blasco B, Bowen HC, Rawlings CJ, Rios JJ, Welham S, Carion PWC, Dupuy LX, King GJ, White PJ, Broadley MR. Genetical and comparative genomics of Brassica under altered Ca supply identifies Arabidopsis Ca-transporter orthologs. THE PLANT CELL 2014; 26:2818-30. [PMID: 25082855 PMCID: PMC4145116 DOI: 10.1105/tpc.114.128603] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 06/09/2014] [Accepted: 07/14/2014] [Indexed: 05/18/2023]
Abstract
Although Ca transport in plants is highly complex, the overexpression of vacuolar Ca(2+) transporters in crops is a promising new technology to improve dietary Ca supplies through biofortification. Here, we sought to identify novel targets for increasing plant Ca accumulation using genetical and comparative genomics. Expression quantitative trait locus (eQTL) mapping to 1895 cis- and 8015 trans-loci were identified in shoots of an inbred mapping population of Brassica rapa (IMB211 × R500); 23 cis- and 948 trans-eQTLs responded specifically to altered Ca supply. eQTLs were screened for functional significance using a large database of shoot Ca concentration phenotypes of Arabidopsis thaliana. From 31 Arabidopsis gene identifiers tagged to robust shoot Ca concentration phenotypes, 21 mapped to 27 B. rapa eQTLs, including orthologs of the Ca(2+) transporters At-CAX1 and At-ACA8. Two of three independent missense mutants of BraA.cax1a, isolated previously by targeting induced local lesions in genomes, have allele-specific shoot Ca concentration phenotypes compared with their segregating wild types. BraA.CAX1a is a promising target for altering the Ca composition of Brassica, consistent with prior knowledge from Arabidopsis. We conclude that multiple-environment eQTL analysis of complex crop genomes combined with comparative genomics is a powerful technique for novel gene identification/prioritization.
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Affiliation(s)
- Neil S Graham
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom
| | - John P Hammond
- School of Agriculture, Policy, and Development, University of Reading, Earley Gate, Whiteknights, Reading RG6 6AR, United Kingdom
| | - Artem Lysenko
- Computational and Systems Biology Department, Rothamsted Research, West Common, Harpenden AL5 2JQ, United Kingdom
| | - Sean Mayes
- Crops for the Future Research Centre, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia
| | - Seosamh O Lochlainn
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom
| | - Bego Blasco
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom
| | - Helen C Bowen
- Warwick HRI, University of Warwick, Wellesbourne CV35 9EF, United Kingdom
| | - Chris J Rawlings
- Computational and Systems Biology Department, Rothamsted Research, West Common, Harpenden AL5 2JQ, United Kingdom
| | - Juan J Rios
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom
| | - Susan Welham
- Computational and Systems Biology Department, Rothamsted Research, West Common, Harpenden AL5 2JQ, United Kingdom
| | - Pierre W C Carion
- Computational and Systems Biology Department, Rothamsted Research, West Common, Harpenden AL5 2JQ, United Kingdom
| | - Lionel X Dupuy
- James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Graham J King
- Southern Cross Plant Science, Southern Cross University, Lismore, New South Wales 2480, Australia
| | - Philip J White
- James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom College of Science, King Saud University, Riyadh 11451, Kingdom of Saudi Arabia
| | - Martin R Broadley
- Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom
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30
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Zhou H, Steffenson BJ, Muehlbauer G, Wanyera R, Njau P, Ndeda S. Association mapping of stem rust race TTKSK resistance in US barley breeding germplasm. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2014; 127:1293-304. [PMID: 24710821 PMCID: PMC4035542 DOI: 10.1007/s00122-014-2297-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 03/12/2014] [Indexed: 05/18/2023]
Abstract
Loci conferring resistance to the highly virulent African stem rust race TTKSK were identified in advanced barley breeding germplasm and positioned to chromosomes 5H and 7H using an association mapping approach. African races of the stem rust pathogen (Puccinia graminis f. sp. tritici) are a serious threat to barley production worldwide because of their wide virulence. To discover and characterize resistance to African stem rust race TTKSK in US barley breeding germplasm, over 3,000 lines/cultivars were assessed for resistance at the seedling stage in the greenhouse and also the adult plant stage in the field in Kenya. Only 12 (0.3 %) and 64 (2.1 %) lines exhibited a resistance level comparable to the resistant control at the seedling and adult plant stage, respectively. To map quantitative trait loci (QTL) for resistance to race TTKSK, an association mapping approach was conducted, utilizing 3,072 single nucleotide polymorphism (SNP) markers. At the seedling stage, two neighboring SNP markers (0.8 cM apart) on chromosome 7H (11_21491 and 12_30528) were found significantly associated with resistance. The most significant one found was 12_30528; thus, the resistance QTL was named Rpg-qtl-7H-12_30528. At the adult plant stage, two SNP markers on chromosome 5H (11_11355 and 12_31427) were found significantly associated with resistance. This resistance QTL was named Rpg-qtl-5H-11_11355 for the most significant marker identified. Adult plant resistance is of paramount importance for stem rust. The marker associated with Rpg-qtl-5H-11_11355 for adult plant resistance explained only a small portion of the phenotypic variation (0.02); however, this QTL reduced disease severity up to 55.0 % under low disease pressure and up to 21.1 % under heavy disease pressure. SNP marker 11_11355 will be valuable for marker-assisted selection of adult plant stem rust resistance in barley breeding.
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Affiliation(s)
- H. Zhou
- Department of Plant Pathology, University of Minnesota, St. Paul, MN USA
| | - B. J. Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, MN USA
| | - Gary Muehlbauer
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN USA
- Department of Plant Biology, University of Minnesota, St. Paul, MN USA
| | - Ruth Wanyera
- Kenya Agricultural Research Institute, Njoro, Kenya
| | - Peter Njau
- Kenya Agricultural Research Institute, Njoro, Kenya
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31
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Alonso-Blanco C, Méndez-Vigo B. Genetic architecture of naturally occurring quantitative traits in plants: an updated synthesis. CURRENT OPINION IN PLANT BIOLOGY 2014; 18:37-43. [PMID: 24565952 DOI: 10.1016/j.pbi.2014.01.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/20/2014] [Accepted: 01/26/2014] [Indexed: 05/08/2023]
Abstract
Deciphering the genetic and molecular bases of quantitative variation is a long-standing challenge in plant biology because it is essential for understanding evolution and for accelerating plant breeding. Recent multi-trait analyses at different phenotypic levels are uncovering the pleiotropy and the genetic regulation underlying high-level complex traits. Thus, the number of known causal loci, genes and nucleotide polymorphisms is expanding. Current plant causal catalogs contain ∼400 genes and natural polymorphisms revealing several dysfunctional allelic series that involve multiple mutations. In addition, repeated evolution of quantitative traits mediated by large effect alleles is found across plant phylogeny. Finally, systematic analyses of genetic and environmental interactions are beginning to elucidate the molecular mechanisms of relevant interactions.
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Affiliation(s)
- Carlos Alonso-Blanco
- Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, Madrid 28049, Spain.
| | - Belén Méndez-Vigo
- Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, Madrid 28049, Spain
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32
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Ballini E, Lauter N, Wise R. Prospects for advancing defense to cereal rusts through genetical genomics. FRONTIERS IN PLANT SCIENCE 2013; 4:117. [PMID: 23641250 PMCID: PMC3640194 DOI: 10.3389/fpls.2013.00117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 04/15/2013] [Indexed: 05/03/2023]
Abstract
Rusts are one of the most severe threats to cereal crops because new pathogen races emerge regularly, resulting in infestations that lead to large yield losses. In 1999, a new race of stem rust, Puccinia graminis f. sp. tritici (Pgt TTKSK or Ug99), was discovered in Uganda. Most of the wheat and barley cultivars grown currently worldwide are susceptible to this new race. Pgt TTKSK has already spread northward into Iran and will likely spread eastward throughout the Indian subcontinent in the near future. This scenario is not unique to stem rust; new races of leaf rust (Puccinia triticina) and stripe rust (Puccinia striiformis) have also emerged recently. One strategy for countering the persistent adaptability of these pathogens is to stack complete- and partial-resistance genes, which requires significant breeding efforts in order to reduce deleterious effects of linkage drag. These varied resistance combinations are typically more difficult for the pathogen to defeat, since they would be predicted to apply lower selection pressure. Genetical genomics or expression Quantitative Trait Locus (eQTL) analysis enables the identification of regulatory loci that control the expression of many to hundreds of genes. Integrated deployment of these technologies coupled with efficient phenotyping offers significant potential to elucidate the regulatory nodes in genetic networks that orchestrate host defense responses. The focus of this review will be to present advances in genetical genomic experimental designs and analysis, particularly as they apply to the prospects for discovering partial disease resistance alleles in cereals.
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Affiliation(s)
| | | | - Roger Wise
- Corn Insects and Crop Genetics Research, Department of Plant Pathology and Microbiology, US Department of Agriculture - Agricultural Research Service, Center for Plant Responses to Environmental Stresses, Iowa State UniversityAmes, IA, USA
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Munkvold JD, Laudencia-Chingcuanco D, Sorrells ME. Systems genetics of environmental response in the mature wheat embryo. Genetics 2013; 194:265-77. [PMID: 23475987 PMCID: PMC3632474 DOI: 10.1534/genetics.113.150052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 02/26/2013] [Indexed: 12/30/2022] Open
Abstract
Quantitative phenotypic traits are influenced by genetic and environmental variables as well as the interaction between the two. Underlying genetic × environment interaction is the influence that the surrounding environment exerts on gene expression. Perturbation of gene expression by environmental factors manifests itself in alterations to gene co-expression networks and ultimately in phenotypic plasticity. Comparative gene co-expression networks have been used to uncover biological mechanisms that differentiate tissues or other biological factors. In this study, we have extended consensus and differential Weighted Gene Co-Expression Network Analysis to compare the influence of different growing environments on gene co-expression in the mature wheat (Triticum aestivum) embryo. This network approach was combined with mapping of individual gene expression QTL to examine the genetic control of environmentally static and variable gene expression. The approach is useful for gene expression experiments containing multiple environments and allowed for the identification of specific gene co-expression modules responsive to environmental factors. This procedure identified conserved coregulation of gene expression between environments related to basic developmental and cellular functions, including protein localization and catabolism, vesicle composition/trafficking, Golgi transport, and polysaccharide metabolism among others. Environmentally unique modules were found to contain genes with predicted functions in responding to abiotic and biotic environmental variables. These findings represent the first report using consensus and differential Weighted Gene Co-expression Network Analysis to characterize the influence of environment on coordinated transcriptional regulation.
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Affiliation(s)
- Jesse D. Munkvold
- Department of Plant Breeding and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
| | - Debbie Laudencia-Chingcuanco
- Genomics and Gene Discovery Unit, U.S. Department of Agriculture–Agricultural Research Service, Western Regional Research Center, Albany, California 94710
| | - Mark E. Sorrells
- Department of Plant Breeding and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14853
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Wang X, Richards J, Gross T, Druka A, Kleinhofs A, Steffenson B, Acevedo M, Brueggeman R. The rpg4-mediated resistance to wheat stem rust (Puccinia graminis) in barley (Hordeum vulgare) requires Rpg5, a second NBS-LRR gene, and an actin depolymerization factor. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:407-18. [PMID: 23216085 DOI: 10.1094/mpmi-06-12-0146-r] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The rpg4 gene confers recessive resistance to several races of wheat stem rust (Puccinia graminis f. sp. tritici) and Rpg5 provides dominant resistance against isolates of the rye stem rust (P. graminis f. sp. secalis) in barley. The rpg4 and Rpg5 genes are tightly linked on chromosome 5H, and positional cloning using high-resolution populations clearly separated the genes, unambiguously identifying Rpg5; however, the identity of rpg4 remained unclear. High-resolution genotyping of critical recombinants at the rpg4/Rpg5 locus, designated here as rpg4-mediated resistance locus (RMRL) delimited two distinct yet tightly linked loci required for resistance, designated as RMRL1 and RMRL2. Utilizing virus-induced gene silencing, each gene at RMRL1, i.e., HvRga1 (a nucleotide-binding site leucine-rich repeat [NBS-LRR] domain gene), Rpg5 (an NBS-LRR-protein kinase domain gene), and HvAdf3 (an actin depolymerizing factor-like gene), was individually silenced followed by inoculation with P. graminis f. sp. tritici race QCCJ. Silencing each gene changed the reaction type from incompatible to compatible, indicating that all three genes are required for rpg4-mediated resistance. This stem rust resistance mechanism in barley follows the emerging theme of unrelated pairs of genetically linked NBS-LRR genes required for specific pathogen recognition and resistance. It also appears that actin cytoskeleton dynamics may play an important role in determining resistance against several races of stem rust in barley.
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Affiliation(s)
- X Wang
- Department of Plant Pathology, North Dakota State University, Fargo, ND, USA
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Bancroft T, Du C, Nettleton D. Estimation of false discovery rate using sequential permutation p-values. Biometrics 2013; 69:1-7. [PMID: 23379645 DOI: 10.1111/j.1541-0420.2012.01825.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We consider the problem of testing each of m null hypotheses with a sequential permutation procedure in which the number of draws from the permutation distribution of each test statistic is a random variable. Each sequential permutation p-value has a null distribution that is nonuniform on a discrete support. We show how to use a collection of such p-values to estimate the number of true null hypotheses m0 among the m null hypotheses tested and how to estimate the false discovery rate (FDR) associated with p-value significance thresholds. We use real data analyses and simulation studies to evaluate and illustrate the performance of our proposed approach relative to standard, more computationally intensive strategies. We find that our sequential approach produces similar results with far less computational expense in a variety of scenarios.
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Affiliation(s)
- Tim Bancroft
- Health Economics and Outcomes Research, OptumInsight, Eden Prairie, Minnesota 55344, USA.
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Li L, Petsch K, Shimizu R, Liu S, Xu WW, Ying K, Yu J, Scanlon MJ, Schnable PS, Timmermans MCP, Springer NM, Muehlbauer GJ. Mendelian and non-Mendelian regulation of gene expression in maize. PLoS Genet 2013; 9:e1003202. [PMID: 23341782 PMCID: PMC3547793 DOI: 10.1371/journal.pgen.1003202] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 11/14/2012] [Indexed: 11/25/2022] Open
Abstract
Transcriptome variation plays an important role in affecting the phenotype of an organism. However, an understanding of the underlying mechanisms regulating transcriptome variation in segregating populations is still largely unknown. We sought to assess and map variation in transcript abundance in maize shoot apices in the intermated B73×Mo17 recombinant inbred line population. RNA–based sequencing (RNA–seq) allowed for the detection and quantification of the transcript abundance derived from 28,603 genes. For a majority of these genes, the population mean, coefficient of variation, and segregation patterns could be predicted by the parental expression levels. Expression quantitative trait loci (eQTL) mapping identified 30,774 eQTL including 96 trans-eQTL “hotspots,” each of which regulates the expression of a large number of genes. Interestingly, genes regulated by a trans-eQTL hotspot tend to be enriched for a specific function or act in the same genetic pathway. Also, genomic structural variation appeared to contribute to cis-regulation of gene expression. Besides genes showing Mendelian inheritance in the RIL population, we also found genes whose expression level and variation in the progeny could not be predicted based on parental difference, indicating that non-Mendelian factors also contribute to expression variation. Specifically, we found 145 genes that show patterns of expression reminiscent of paramutation such that all the progeny had expression levels similar to one of the two parents. Furthermore, we identified another 210 genes that exhibited unexpected patterns of transcript presence/absence. Many of these genes are likely to be gene fragments resulting from transposition, and the presence/absence of their transcripts could influence expression levels of their ancestral syntenic genes. Overall, our results contribute to the identification of novel expression patterns and broaden the understanding of transcriptional variation in plants. Phenotypes are determined by the expression of genes, the environment, and the interaction of gene expression and the environment. However, a complete understanding of the inheritance of and genome-wide regulation of gene expression is lacking. One approach, called expression quantitative trait locus (eQTL) mapping provides the opportunity to examine the genome-wide inheritance and regulation of gene expression. In this paper, we conducted high-throughput sequencing of gene transcripts to examine gene expression in the shoot apex of a maize biparental mapping population. We quantified expression levels from 28,603 genes in the population and showed that the vast majority of genes exhibited the expected pattern of Mendelian inheritance. We genetically mapped the expression patterns and identified genomic regions associated with gene expression. Notably, we detected gene expression patterns that exhibited non-Mendelian inheritance. These included 145 genes that exhibited expression patterns in the progeny that were similar to only one of the parents and 210 genes with unexpected presence/absence expression patterns. The findings of non-Mendelian inheritance underscore the complexity of gene expression and provide a framework for understanding these complexities.
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Affiliation(s)
- Lin Li
- Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Katherine Petsch
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Rena Shimizu
- Department of Plant Biology, Cornell University, Ithaca, New York, United States of America
| | - Sanzhen Liu
- Department of Genetics, Development, and Cell Biology, and Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | - Wayne Wenzhong Xu
- Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Kai Ying
- Department of Genetics, Development, and Cell Biology, and Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | - Jianming Yu
- Department of Agronomy, Kansas State University, Manhattan, Kansas, United States of America
| | - Michael J. Scanlon
- Department of Plant Biology, Cornell University, Ithaca, New York, United States of America
| | - Patrick S. Schnable
- Department of Genetics, Development, and Cell Biology, and Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | | | - Nathan M. Springer
- Department of Plant Biology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Gary J. Muehlbauer
- Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, Minnesota, United States of America
- Department of Plant Biology, University of Minnesota, Saint Paul, Minnesota, United States of America
- * E-mail:
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37
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Cubillos FA, Coustham V, Loudet O. Lessons from eQTL mapping studies: non-coding regions and their role behind natural phenotypic variation in plants. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:192-8. [PMID: 22265229 DOI: 10.1016/j.pbi.2012.01.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 12/17/2011] [Accepted: 01/03/2012] [Indexed: 05/24/2023]
Abstract
Even if considerable progress has been achieved towards the understanding of natural variation in plant systems, the contribution of transcript abundance variation to phenotypic diversity remains unappreciated. Over the last decade, efforts to characterise the genome-wide expression variation in natural accessions, structured populations and hybrids have improved our knowledge of the contribution of non-coding polymorphisms to gene expression regulation. Moreover, new studies are helping to unravel the role of expression polymorphisms and their orchestrated performance. Recent advances involving classical linkage analysis, GWAS and improved eQTL mapping strategies will provide a greater resolution to determine the genetic variants shaping the broad diversity in plant systems.
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Affiliation(s)
- Francisco A Cubillos
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, F-78000 Versailles, France
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