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Salgotra RK, Thompson M, Chauhan BS. Unravelling the genetic potential of untapped crop wild genetic resources for crop improvement. CONSERV GENET RESOUR 2021. [DOI: 10.1007/s12686-021-01242-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Henningsen E, Sallam AH, Matny O, Szinyei T, Figueroa M, Steffenson BJ. Rpg7: A New Gene for Stem Rust Resistance from Hordeum vulgare ssp. spontaneum. PHYTOPATHOLOGY 2021; 111:548-558. [PMID: 32880513 DOI: 10.1094/phyto-08-20-0325-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: 06/11/2023]
Abstract
Wheat stem rust (causal organism: Puccinia graminis f. sp. tritici) is an important fungal disease that causes significant yield losses in barley. The deployment of resistant cultivars is the most effective means of controlling this disease. Stem rust evaluations of a diverse collection of wild barley (Hordeum vulgare ssp. spontaneum) identified two Jordanian accessions (WBDC094 and WBDC238) with resistance to a virulent pathotype (P. graminis f. sp. tritici HKHJC) from the United States. To elucidate the genetics of stem rust resistance, both accessions were crossed to the susceptible landrace Hiproly. Segregation ratios of F2 and F3 progeny indicated that a single dominant gene confers resistance to P. graminis f. sp. tritici HKHJC. Molecular mapping of the resistance locus was performed in the Hiproly/WBDC238 F2 population based on 3,329 single-nucleotide polymorphism markers generated by genotyping-by-sequencing. Quantitative trait locus analysis positioned the resistance gene to the long arm of chromosome 3H between the physical/genetic positions of 683.8 Mbp/172.9 cM and 693.7 Mbp/176.0 cM. Because this resistance gene is novel, it was assigned the new gene locus symbol of Rpg7 with a corresponding allele symbol of Rpg7.i. At the seedling stage, Rpg7 confers resistance against a number of other important P. graminis f. sp. tritici pathotypes from the United States (MCCFC, QCCJB, and TTTTF) and Africa (TTKSK) as well as an isolate (92-MN-90) of the rye stem rust pathogen (P. graminis f. sp. secalis) from Minnesota. The resistance conferred by Rpg7 can be readily transferred into breeding programs because of its simple inheritance and clear phenotypic expression.
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Affiliation(s)
- Eva Henningsen
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Ahmad H Sallam
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Oadi Matny
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Tamas Szinyei
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
| | - Melania Figueroa
- Commonwealth Scientific and Industrial Research Organization, Agriculture and Food, Canberra, ACT 2601, Australia
| | - Brian J Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, U.S.A
- Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul, MN 55108, U.S.A
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Si E, Meng Y, Ma X, Li B, Wang J, Yao L, Yang K, Zhang Y, Shang X, Wang H. Genome Resource for Barley Leaf Stripe Pathogen Pyrenophora graminea. PLANT DISEASE 2020; 104:320-322. [PMID: 31804900 DOI: 10.1094/pdis-06-19-1179-a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Pyrenophora graminea is the causative agent of barley leaf stripe disease. In this study, the strong pathogenic isolate QWC was used to generate DNA for Illumina sequencing. After assembly, its genome size was 42.5 Mb, consisting of 264 scaffolds, and a total of 10,376 genes was predicted. This is the first genome resource available for P. graminea. The genome sequences of P. graminea will accelerate the understanding interaction of P. graminea and barley.
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Affiliation(s)
- Erjing Si
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China
| | - Yaxiong Meng
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China
| | - Xiaole Ma
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China
| | - Baochun Li
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China
| | - Juncheng Wang
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China
| | - Lirong Yao
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China
| | - Ke Yang
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China
| | - Yu Zhang
- Gansu Plant Seed Administrative Station, Lanzhou 730020, China
| | - Xunwu Shang
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
| | - Huajun Wang
- Gansu Provincial Key Laboratory of Aridland and Crop Science/Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, 730070, China
- College of Agronomy, Gansu Agricultural University, Lanzhou, 730070, China
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Liu M, Li Y, Ma Y, Zhao Q, Stiller J, Feng Q, Tian Q, Liu D, Han B, Liu C. The draft genome of a wild barley genotype reveals its enrichment in genes related to biotic and abiotic stresses compared to cultivated barley. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:443-456. [PMID: 31314154 PMCID: PMC6953193 DOI: 10.1111/pbi.13210] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 07/13/2019] [Indexed: 05/06/2023]
Abstract
Wild barley (Hordeum spontaneum) is the progenitor of cultivated barley (Hordeum vulgare) and provides a rich source of genetic variations for barley improvement. Currently, the genome sequences of wild barley and its differences with cultivated barley remain unclear. In this study, we report a high-quality draft assembly of wild barley accession (AWCS276; henceforth named as WB1), which consists of 4.28 Gb genome and 36 395 high-confidence protein-coding genes. BUSCO analysis revealed that the assembly included full lengths of 95.3% of the 956 single-copy plant genes, illustrating that the gene-containing regions have been well assembled. By comparing with the genome of the cultivated genotype Morex, it is inferred that the WB1 genome contains more genes involved in resistance and tolerance to biotic and abiotic stresses. The presence of the numerous WB1-specific genes indicates that, in addition to enhance allele diversity for genes already existing in the cultigen, exploiting the wild barley taxon in breeding should also allow the incorporation of novel genes. Furthermore, high levels of genetic variation in the pericentromeric regions were detected in chromosomes 3H and 5H between the wild and cultivated genotypes, which may be the results of domestication. This H. spontaneum draft genome assembly will help to accelerate wild barley research and be an invaluable resource for barley improvement and comparative genomics research.
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Affiliation(s)
- Miao Liu
- CSIRO Agriculture and FoodSt LuciaQldAustralia
- Crop Research InstituteSichuan Academy of Agricultural SciencesJinjiang District, ChengduChina
- Triticeae Research InstituteSichuan Agricultural UniversityWenjiang, ChengduChina
| | - Yan Li
- National Center for Gene ResearchChinese Academy of SciencesShanghaiChina
| | - Yanling Ma
- CSIRO Agriculture and FoodSt LuciaQldAustralia
- Institute of Crop SciencesChinese Academy of Agricultural SciencesHaidian District, BeijingChina
| | - Qiang Zhao
- National Center for Gene ResearchChinese Academy of SciencesShanghaiChina
| | | | - Qi Feng
- National Center for Gene ResearchChinese Academy of SciencesShanghaiChina
| | - Qilin Tian
- National Center for Gene ResearchChinese Academy of SciencesShanghaiChina
| | - Dengcai Liu
- Triticeae Research InstituteSichuan Agricultural UniversityWenjiang, ChengduChina
| | - Bin Han
- National Center for Gene ResearchChinese Academy of SciencesShanghaiChina
| | - Chunji Liu
- CSIRO Agriculture and FoodSt LuciaQldAustralia
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Brozynska M, Furtado A, Henry RJ. Genomics of crop wild relatives: expanding the gene pool for crop improvement. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:1070-85. [PMID: 26311018 DOI: 10.1111/pbi.12454] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 06/26/2015] [Accepted: 07/16/2015] [Indexed: 05/20/2023]
Abstract
Plant breeders require access to new genetic diversity to satisfy the demands of a growing human population for more food that can be produced in a variable or changing climate and to deliver the high-quality food with nutritional and health benefits demanded by consumers. The close relatives of domesticated plants, crop wild relatives (CWRs), represent a practical gene pool for use by plant breeders. Genomics of CWR generates data that support the use of CWR to expand the genetic diversity of crop plants. Advances in DNA sequencing technology are enabling the efficient sequencing of CWR and their increased use in crop improvement. As the sequencing of genomes of major crop species is completed, attention has shifted to analysis of the wider gene pool of major crops including CWR. A combination of de novo sequencing and resequencing is required to efficiently explore useful genetic variation in CWR. Analysis of the nuclear genome, transcriptome and maternal (chloroplast and mitochondrial) genome of CWR is facilitating their use in crop improvement. Genome analysis results in discovery of useful alleles in CWR and identification of regions of the genome in which diversity has been lost in domestication bottlenecks. Targeting of high priority CWR for sequencing will maximize the contribution of genome sequencing of CWR. Coordination of global efforts to apply genomics has the potential to accelerate access to and conservation of the biodiversity essential to the sustainability of agriculture and food production.
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Affiliation(s)
- Marta Brozynska
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Qld, Australia
| | - Agnelo Furtado
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Qld, Australia
| | - Robert J Henry
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Qld, Australia
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Biselli C, Urso S, Tacconi G, Steuernagel B, Schulte D, Gianinetti A, Bagnaresi P, Stein N, Cattivelli L, Valè G. Haplotype variability and identification of new functional alleles at the Rdg2a leaf stripe resistance gene locus. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2013; 126:1575-1586. [PMID: 23494394 DOI: 10.1007/s00122-013-2075-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/23/2013] [Indexed: 06/01/2023]
Abstract
The barley Rdg2a locus confers resistance to the leaf stripe pathogen Pyrenophora graminea and, in the barley genotype Thibaut, it is composed of a gene family with three highly similar paralogs. Only one member of the gene family (called as Rdg2a) encoding for a CC-NB-LRR protein is able to confer resistance to the leaf stripe isolate Dg2. To study the genome evolution and diversity at the Rdg2a locus, sequences spanning the Rdg2a gene were compared in two barley cultivars, Thibaut and Morex, respectively, resistant and susceptible to leaf stripe. An overall high level of sequence conservation interrupted by several rearrangements that included three main deletions was observed in the Morex contig. The main deletion of 13,692 bp was most likely derived from unequal crossing over between Rdg2a paralogs leading to the generation of a chimeric Morex rdg2a gene which was not associated to detectable level of resistance toward leaf stripe. PCR-based analyses of genic and intergenic regions at the Rdg2a locus in 29 H. vulgare lines and one H. vulgare ssp. spontaneum accession indicated large haplotype variability in the cultivated barley gene pool suggesting rapid and recent divergence at this locus. Barley genotypes showing the same haplotype as Thibaut at the Rdg2a locus were selected for a Rdg2a allele mining through allele re-sequencing and two lines with polymorphic nucleotides leading to amino acid changes in the CC-NB and LRR encoding domains, respectively, were identified. Analysis of nucleotide diversity of the Rdg2a alleles revealed that the polymorphic sites were subjected to positive selection. Moreover, strong positively selected sites were located in the LRR encoding domain suggesting that both positive selection and divergence at homologous loci are possibly representing the molecular mechanism for the generation of high diversity at the Rdg2a locus in the barley gene pool.
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Affiliation(s)
- Chiara Biselli
- Genomics Research Centre, CRA-Consiglio per la ricerca e la sperimentazione in agricoltura, Via S Protaso 302, 29017 Fiorenzuola d'Arda, Piacenza, Italy
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The CC-NB-LRR-type Rdg2a resistance gene confers immunity to the seed-borne barley leaf stripe pathogen in the absence of hypersensitive cell death. PLoS One 2010; 5. [PMID: 20844752 PMCID: PMC2937021 DOI: 10.1371/journal.pone.0012599] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 08/12/2010] [Indexed: 01/04/2023] Open
Abstract
Background Leaf stripe disease on barley (Hordeum vulgare) is caused by the seed-transmitted hemi-biotrophic fungus Pyrenophora graminea. Race-specific resistance to leaf stripe is controlled by two known Rdg (Resistance to Drechslera graminea) genes: the H. spontaneum-derived Rdg1a and Rdg2a, identified in H. vulgare. The aim of the present work was to isolate the Rdg2a leaf stripe resistance gene, to characterize the Rdg2a locus organization and evolution and to elucidate the histological bases of Rdg2a-based leaf stripe resistance. Principal Findings We describe here the positional cloning and functional characterization of the leaf stripe resistance gene Rdg2a. At the Rdg2a locus, three sequence-related coiled-coil, nucleotide-binding site, and leucine-rich repeat (CC-NB-LRR) encoding genes were identified. Sequence comparisons suggested that paralogs of this resistance locus evolved through recent gene duplication, and were subjected to frequent sequence exchange. Transformation of the leaf stripe susceptible cv. Golden Promise with two Rdg2a-candidates under the control of their native 5′ regulatory sequences identified a member of the CC-NB-LRR gene family that conferred resistance against the Dg2 leaf stripe isolate, against which the Rdg2a-gene is effective. Histological analysis demonstrated that Rdg2a-mediated leaf stripe resistance involves autofluorescing cells and prevents pathogen colonization in the embryos without any detectable hypersensitive cell death response, supporting a cell wall reinforcement-based resistance mechanism. Conclusions This work reports about the cloning of a resistance gene effective against a seed borne disease. We observed that Rdg2a was subjected to diversifying selection which is consistent with a model in which the R gene co-evolves with a pathogen effector(s) gene. We propose that inducible responses giving rise to physical and chemical barriers to infection in the cell walls and intercellular spaces of the barley embryo tissues represent mechanisms by which the CC-NB-LRR-encoding Rdg2a gene mediates resistance to leaf stripe in the absence of hypersensitive cell death.
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