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Schmidt N, Sielemann K, Breitenbach S, Fuchs J, Pucker B, Weisshaar B, Holtgräwe D, Heitkam T. Repeat turnover meets stable chromosomes: repetitive DNA sequences mark speciation and gene pool boundaries in sugar beet and wild beets. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:171-190. [PMID: 38128038 DOI: 10.1111/tpj.16599] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023]
Abstract
Sugar beet and its wild relatives share a base chromosome number of nine and similar chromosome morphologies. Yet, interspecific breeding is impeded by chromosome and sequence divergence that is still not fully understood. Since repetitive DNAs are among the fastest evolving parts of the genome, we investigated, if repeatome innovations and losses are linked to chromosomal differentiation and speciation. We traced genome and chromosome-wide evolution across 13 beet species comprising all sections of the genera Beta and Patellifolia. For this, we combined short and long read sequencing, flow cytometry, and cytogenetics to build a comprehensive framework that spans the complete scale from DNA to chromosome to genome. Genome sizes and repeat profiles reflect the separation into three gene pools with contrasting evolutionary patterns. Among all repeats, satellite DNAs harbor most genomic variability, leading to fundamentally different centromere architectures, ranging from chromosomal uniformity in Beta and Patellifolia to the formation of patchwork chromosomes in Corollinae/Nanae. We show that repetitive DNAs are causal for the genome expansions and contractions across the beet genera, providing insights into the genomic underpinnings of beet speciation. Satellite DNAs in particular vary considerably between beet genomes, leading to the evolution of distinct chromosomal setups in the three gene pools, likely contributing to the barriers in beet breeding. Thus, with their isokaryotypic chromosome sets, beet genomes present an ideal system for studying the link between repeats, genomic variability, and chromosomal differentiation and provide a theoretical fundament for understanding barriers in any crop breeding effort.
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Affiliation(s)
- Nicola Schmidt
- Faculty of Biology, Technische Universität Dresden, 01069, Dresden, Germany
| | - Katharina Sielemann
- Genetics and Genomics of Plants, Center for Biotechnology (CeBiTec) & Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany
- Graduate School DILS, Bielefeld Institute for Bioinformatics Infrastructure (BIBI), Bielefeld University, 33615, Bielefeld, Germany
| | - Sarah Breitenbach
- Faculty of Biology, Technische Universität Dresden, 01069, Dresden, Germany
| | - Jörg Fuchs
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Stadt Seeland, Germany
| | - Boas Pucker
- Plant Biotechnology and Bioinformatics, Institute of Plant Biology & Braunschweig Integrated Centre of Systems Biology (BRICS), TU Braunschweig, 38106, Braunschweig, Germany
| | - Bernd Weisshaar
- Genetics and Genomics of Plants, Center for Biotechnology (CeBiTec) & Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany
| | - Daniela Holtgräwe
- Genetics and Genomics of Plants, Center for Biotechnology (CeBiTec) & Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany
| | - Tony Heitkam
- Faculty of Biology, Technische Universität Dresden, 01069, Dresden, Germany
- Institute of Biology, NAWI Graz, Karl-Franzens-Universität, A-8010 Graz, Graz, Austria
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Khoshnami M, Zare B, Mardani-Mehrabad H, Rakhshandehroo F, Baghery MA, Malboobi MA. Assessment of co-infection with BNYVV and BSCTV on resistance against Rhizomania disease in transgenic sugar beet plants. Transgenic Res 2023; 32:475-485. [PMID: 37656262 DOI: 10.1007/s11248-023-00364-8] [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: 09/13/2022] [Accepted: 08/17/2023] [Indexed: 09/02/2023]
Abstract
Sugar beet is an economically important crop and one of the major sources of sucrose around the world. Beet necrotic yellow vein virus (BNYVV) and Beet severe curly top virus (BSCTV) are two widespread viruses in sugar beet that cause severe damage to its performance. Previously, we have successfully produced resistance to BNYVV based on RNA silencing in sugar beet by introducing constructs carrying the viral coat-protein-encoding DNA sequence, CP21, in sense and anti-sense orientations. Yet, the RNA silencing-mediated resistance to a specific virus could be affected by other ones as a part of synergistic interactions. In this study, we assayed the specificity of the induced resistance against BNYVV in two sets of transgenic events, S3 and S6 carrying 5'-UTR with or without CP21-coding sequences, respectively. These events were subjected to viral challenges with either BNYVV, an Iranian isolate of BSCTV (BSCTV-Ir) or both. All the plants inoculated with just BSCTV-Ir displayed curly-leaf symptoms. However, partial resistance was evident in S3 events as shown by mild symptoms and reduced PCR amplification of the BSCTV-Ir coat protein encoding sequence. Based on the presented data, resistance to BNYVV was stable in almost all the transgenic plants co-infected with BSCTV-Ir, except for one event, S3-229. In general, it seems that the co-infection does not affect the resistance to BNYVV in transgenic plants. These findings demonstrated that the introduced RNA silencing-mediated resistance against BNYVV in transgenic sugar beets is specific and is not suppressed after co-infection with a heterologous virus.
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Affiliation(s)
- Maryam Khoshnami
- Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Pazhouhesh Boulevard, Karaj Highway, Tehran, Iran
- Department of Plant Pathology, College of Agriculture and Natural Resources, Science and Research Branch, Islamic Azad University, Shohadaye Hesarak Boulevard, Daneshgah Square, Satary Highway, Tehran, Iran
| | - Bahar Zare
- Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Pazhouhesh Boulevard, Karaj Highway, Tehran, Iran
| | - Hamideh Mardani-Mehrabad
- Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Pazhouhesh Boulevard, Karaj Highway, Tehran, Iran
- Department of Plant Pathology, College of Agriculture and Natural Resources, Science and Research Branch, Islamic Azad University, Shohadaye Hesarak Boulevard, Daneshgah Square, Satary Highway, Tehran, Iran
| | - Farshad Rakhshandehroo
- Department of Plant Pathology, College of Agriculture and Natural Resources, Science and Research Branch, Islamic Azad University, Shohadaye Hesarak Boulevard, Daneshgah Square, Satary Highway, Tehran, Iran
| | - Mohammad Amin Baghery
- Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Pazhouhesh Boulevard, Karaj Highway, Tehran, Iran
| | - Mohammad Ali Malboobi
- Department of Plant Biotechnology, National Institute of Genetic Engineering and Biotechnology, Pazhouhesh Boulevard, Karaj Highway, Tehran, Iran.
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Guo T, Bao R, Yang Z, Fu X, Hu L, Wang N, Liu C, Ma F. The m 6 A reader MhYTP2 negatively modulates apple Glomerella leaf spot resistance by binding to and degrading MdRGA2L mRNA. MOLECULAR PLANT PATHOLOGY 2023; 24:1287-1299. [PMID: 37366340 PMCID: PMC10502827 DOI: 10.1111/mpp.13370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 06/04/2023] [Accepted: 06/08/2023] [Indexed: 06/28/2023]
Abstract
Glomerella leaf spot (GLS), caused by the fungal pathogen Colletotrichum fructicola, significantly threatens apple production. Some resistances to plant disease are mediated by the accumulation of nucleotide-binding site and leucine-rich repeat (NBS-LRR) proteins that are encoded by a major class of plant disease resistance genes (R genes). However, the R genes that confer resistance to GLS in apple remain largely unclear. Malus hupehensis YT521-B homology domain-containing protein 2 (MhYTP2) was identified as an N6 -methyladenosine RNA methylation (m6 A) modified RNA reader in our previous study. However, whether MhYTP2 binds to mRNAs without m6 A RNA modifications remains unknown. In this study, we discovered that MhYTP2 exerts both m6 A-dependent and -independent functions by analysing previously obtained RNA immunoprecipitation sequencing results. The overexpression of MhYTP2 significantly reduced the resistance of apple to GLS and down-regulated the transcript levels of some R genes whose transcripts do not contain m6 A modifications. Further analysis indicated that MhYTP2 binds to and reduces the stability of MdRGA2L mRNA. MdRGA2L positively regulates resistance to GLS by activating salicylic acid signalling. Our findings revealed that MhYTP2 plays an essential role in the regulation of resistance to GLS and identified a promising R gene, MdRGA2L, for use in developing apple cultivars with GLS resistance.
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Affiliation(s)
- Tianli Guo
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
| | - Ru Bao
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
| | - Zehua Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
| | - Xiaomin Fu
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
| | - Liu Hu
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
| | - Na Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
| | - Changhai Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
| | - Fengwang Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of AppleCollege of Horticulture, Northwest A&F UniversityYanglingChina
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Taniguchi E, Satoh K, Ohkubo M, Ue S, Matsuhira H, Kuroda Y, Kubo T, Kitazaki K. Nuclear DNA segments homologous to mitochondrial DNA are obstacles for detecting heteroplasmy in sugar beet (Beta vulgaris L.). PLoS One 2023; 18:e0285430. [PMID: 37552681 PMCID: PMC10409277 DOI: 10.1371/journal.pone.0285430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 04/21/2023] [Indexed: 08/10/2023] Open
Abstract
Heteroplasmy, the coexistence of multiple mitochondrial DNA (mtDNA) sequences in a cell, is well documented in plants. Next-generation sequencing technology (NGS) has made it feasible to sequence entire genomes. Thus, NGS has the potential to detect heteroplasmy; however, the methods and pitfalls in heteroplasmy detection have not been fully investigated and identified. One obstacle for heteroplasmy detection is the sequence homology between mitochondrial-, plastid-, and nuclear DNA, of which the influence of nuclear DNA segments homologous to mtDNA (numt) need to be minimized. To detect heteroplasmy, we first excluded nuclear DNA sequences of sugar beet (Beta vulgaris) line EL10 from the sugar beet mtDNA sequence. NGS reads were obtained from single plants of sugar beet lines NK-195BRmm-O and NK-291BRmm-O and mapped to the unexcluded mtDNA regions. More than 1000 sites exhibited intra-individual polymorphism as detected by genome browsing analysis. We focused on a 309-bp region where 12 intra-individual polymorphic sites were closely linked to each other. Although the existence of DNA molecules having variant alleles at the 12 sites was confirmed by PCR amplification from NK-195BRmm-O and NK-291BRmm-O, these variants were not always called by six variant-calling programs, suggesting that these programs are inappropriate for intra-individual polymorphism detection. When we changed the nuclear DNA reference, a numt absent from EL10 was found to include the 309-bp region. Genetic segregation of an F2 population from NK-195BRmm-O x NK-291BRmm-O supported the numt origin of the variant alleles. Using four references, we found that numt detection exhibited reference dependency, and extreme polymorphism of numts exists among sugar beet lines. One of the identified numts absent from EL10 is also associated with another intra-individual polymorphic site in NK-195mm-O. Our data suggest that polymorphism among numts is unexpectedly high within sugar beets, leading to confusion about the true degree of heteroplasmy.
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Affiliation(s)
- Eigo Taniguchi
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kosuke Satoh
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Megumi Ohkubo
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Sachiyo Ue
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Hiroaki Matsuhira
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Memuro, Hokkaido, Japan
| | - Yosuke Kuroda
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Memuro, Hokkaido, Japan
| | - Tomohiko Kubo
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kazuyoshi Kitazaki
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
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Guimaraes PM, Quintana AC, Mota APZ, Berbert PS, Ferreira DDS, de Aguiar MN, Pereira BM, de Araújo ACG, Brasileiro ACM. Engineering Resistance against Sclerotinia sclerotiorum Using a Truncated NLR (TNx) and a Defense-Priming Gene. PLANTS (BASEL, SWITZERLAND) 2022; 11:3483. [PMID: 36559595 PMCID: PMC9786959 DOI: 10.3390/plants11243483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
The association of both cell-surface PRRs (Pattern Recognition Receptors) and intracellular receptor NLRs (Nucleotide-Binding Leucine-Rich Repeat) in engineered plants have the potential to activate strong defenses against a broad range of pathogens. Here, we describe the identification, characterization, and in planta functional analysis of a novel truncated NLR (TNx) gene from the wild species Arachis stenosperma (AsTIR19), with a protein structure lacking the C-terminal LRR (Leucine Rich Repeat) domain involved in pathogen perception. Overexpression of AsTIR19 in tobacco plants led to a significant reduction in infection caused by Sclerotinia sclerotiorum, with a further reduction in pyramid lines containing an expansin-like B gene (AdEXLB8) potentially involved in defense priming. Transcription analysis of tobacco transgenic lines revealed induction of hormone defense pathways (SA; JA-ET) and PRs (Pathogenesis-Related proteins) production. The strong upregulation of the respiratory burst oxidase homolog D (RbohD) gene in the pyramid lines suggests its central role in mediating immune responses in plants co-expressing the two transgenes, with reactive oxygen species (ROS) production enhanced by AdEXLB8 cues leading to stronger defense response. Here, we demonstrate that the association of potential priming elicitors and truncated NLRs can produce a synergistic effect on fungal resistance, constituting a promising strategy for improved, non-specific resistance to plant pathogens.
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Affiliation(s)
- Patricia Messenberg Guimaraes
- Embrapa Genetic Resources and Biotechnology, Brasilia 70770-917, Brazil
- National Institute of Science and Technology (INCT Plant Stress Biotech), Brasilia 70770-917, Brazil
| | | | - Ana Paula Zotta Mota
- INRAE, Institut Sophia Agrobiotech, CNRS, Université Côte d’Azur, 06903 Sophia Antipolis, France
| | | | | | | | | | | | - Ana Cristina Miranda Brasileiro
- Embrapa Genetic Resources and Biotechnology, Brasilia 70770-917, Brazil
- National Institute of Science and Technology (INCT Plant Stress Biotech), Brasilia 70770-917, Brazil
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Li X, He W, Fang J, Liang Y, Zhang H, Chen D, Wu X, Zhang Z, Wang L, Han P, Zhang B, Xue T, Zheng W, He J, Bai C. Genomic and transcriptomic-based analysis of agronomic traits in sugar beet ( Beta vulgaris L.) pure line IMA1. FRONTIERS IN PLANT SCIENCE 2022; 13:1028885. [PMID: 36311117 PMCID: PMC9608375 DOI: 10.3389/fpls.2022.1028885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Sugar beet (Beta vulgaris L.) is an important sugar-producing and energy crop worldwide. The sugar beet pure line IMA1 independently bred by Chinese scientists is a standard diploid parent material that is widely used in hybrid-breeding programs. In this study, a high-quality, chromosome-level genome assembly for IMA1was conducted, and 99.1% of genome sequences were assigned to nine chromosomes. A total of 35,003 protein-coding genes were annotated, with 91.56% functionally annotated by public databases. Compared with previously released sugar beet assemblies, the new genome was larger with at least 1.6 times larger N50 size, thereby substantially improving the completeness and continuity of the sugar beet genome. A Genome-Wide Association Studies analysis identified 10 disease-resistance genes associated with three important beet diseases and five genes associated with sugar yield per hectare, which could be key targets to improve sugar productivity. Nine highly expressed genes associated with pollen fertility of sugar beet were also identified. The results of this study provide valuable information to identify and dissect functional genes affecting sugar beet agronomic traits, which can increase sugar beet production and help screen for excellent sugar beet breeding materials. In addition, information is provided that can precisely incorporate biotechnology tools into breeding efforts.
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Affiliation(s)
- Xiaodong Li
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Wenjin He
- Life Science College of Fujian Normal University, Fuzhou, China
| | - Jingping Fang
- Life Science College of Fujian Normal University, Fuzhou, China
| | - Yahui Liang
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Huizhong Zhang
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Duo Chen
- Life Science College of Fujian Normal University, Fuzhou, China
| | - Xingrong Wu
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Ziqiang Zhang
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Liang Wang
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Pingan Han
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Bizhou Zhang
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Ting Xue
- Life Science College of Fujian Normal University, Fuzhou, China
| | - Wenzhe Zheng
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Jiangfeng He
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
| | - Chen Bai
- Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
- Inner Mongolia Key Laboratory of Sugarbeet Genetics & Germplasm Enhancement, Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences, Hohhot, China
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McGrath JM, Funk A, Galewski P, Ou S, Townsend B, Davenport K, Daligault H, Johnson S, Lee J, Hastie A, Darracq A, Willems G, Barnes S, Liachko I, Sullivan S, Koren S, Phillippy A, Wang J, Liu T, Pulman J, Childs K, Shu S, Yocum A, Fermin D, Mutasa-Göttgens E, Stevanato P, Taguchi K, Naegele R, Dorn KM. A contiguous de novo genome assembly of sugar beet EL10 (Beta vulgaris L.). DNA Res 2022; 30:6748264. [PMID: 36208288 PMCID: PMC9896481 DOI: 10.1093/dnares/dsac033] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/26/2022] [Accepted: 09/12/2022] [Indexed: 02/04/2023] Open
Abstract
A contiguous assembly of the inbred 'EL10' sugar beet (Beta vulgaris ssp. vulgaris) genome was constructed using PacBio long-read sequencing, BioNano optical mapping, Hi-C scaffolding, and Illumina short-read error correction. The EL10.1 assembly was 540 Mb, of which 96.2% was contained in nine chromosome-sized pseudomolecules with lengths from 52 to 65 Mb, and 31 contigs with a median size of 282 kb that remained unassembled. Gene annotation incorporating RNA-seq data and curated sequences via the MAKER annotation pipeline generated 24,255 gene models. Results indicated that the EL10.1 genome assembly is a contiguous genome assembly highly congruent with the published sugar beet reference genome. Gross duplicate gene analyses of EL10.1 revealed little large-scale intra-genome duplication. Reduced gene copy number for well-annotated gene families relative to other core eudicots was observed, especially for transcription factors. Variation in genome size in B. vulgaris was investigated by flow cytometry among 50 individuals producing estimates from 633 to 875 Mb/1C. Read-depth mapping with short-read whole-genome sequences from other sugar beet germplasm suggested that relatively few regions of the sugar beet genome appeared associated with high-copy number variation.
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Affiliation(s)
| | - Andrew Funk
- Plant Breeding, Genetics, and Biotechnology Program, Michigan State University, East Lansing, MI 48824, USA
| | - Paul Galewski
- Plant Breeding, Genetics, and Biotechnology Program, Michigan State University, East Lansing, MI 48824, USA
| | - Shujun Ou
- Plant Breeding, Genetics, and Biotechnology Program, Michigan State University, East Lansing, MI 48824, USA
| | - Belinda Townsend
- Department of Plant Sciences, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Karen Davenport
- Los Alamos Nat’l Lab, Biosecurity and Public Health, Los Alamos, NM 87545, USA
| | - Hajnalka Daligault
- Los Alamos Nat’l Lab, Biosecurity and Public Health, Los Alamos, NM 87545, USA
| | - Shannon Johnson
- Los Alamos Nat’l Lab, Biosecurity and Public Health, Los Alamos, NM 87545, USA
| | - Joyce Lee
- BioNano Genomics, 9640 Towne Centre Drive, San Diego, CA 92121, USA
| | - Alex Hastie
- BioNano Genomics, 9640 Towne Centre Drive, San Diego, CA 92121, USA
| | - Aude Darracq
- SESVANDERHAVE N.V., Industriepark Soldatenplein Zone 2 Nr 15, 3300 Tienen, Belgium
| | - Glenda Willems
- SESVANDERHAVE N.V., Industriepark Soldatenplein Zone 2 Nr 15, 3300 Tienen, Belgium
| | - Steve Barnes
- SESVANDERHAVE N.V., Industriepark Soldatenplein Zone 2 Nr 15, 3300 Tienen, Belgium
| | - Ivan Liachko
- Phase Genomics, 4000 Mason Road, Suite 225, Seattle, WA 98195, USA
| | - Shawn Sullivan
- Phase Genomics, 4000 Mason Road, Suite 225, Seattle, WA 98195, USA
| | - Sergey Koren
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD, USA
| | - Adam Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD, USA
| | - Jie Wang
- Center for Genomics-Enabled Plant Science, Plant Biology Department, Michigan State University, East Lansing, MI 48824, USA
| | - Tiffany Liu
- Center for Genomics-Enabled Plant Science, Plant Biology Department, Michigan State University, East Lansing, MI 48824, USA
| | - Jane Pulman
- Center for Genomics-Enabled Plant Science, Plant Biology Department, Michigan State University, East Lansing, MI 48824, USA
| | - Kevin Childs
- Center for Genomics-Enabled Plant Science, Plant Biology Department, Michigan State University, East Lansing, MI 48824, USA
| | - Shengqiang Shu
- United States Department of Energy, Joint Genome Institute, Berkeley, CA, USA
| | | | | | - Effie Mutasa-Göttgens
- University of Hertfordshire, Division of Biosciences, Hatfield, Hertfordshire AL10 9AB, UK
| | | | - Kazunori Taguchi
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Shinsei Memuro, Hokkaido 082-0081, Japan
| | - Rachel Naegele
- USDA-ARS Sugarbeet and Bean Research Unit, Michigan State University, 1066 Bogue St., East Lansing, MI 48824, USA
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A TIR-NBS-LRR Gene MdTNL1 Regulates Resistance to Glomerella Leaf Spot in Apple. Int J Mol Sci 2022; 23:ijms23116323. [PMID: 35683002 PMCID: PMC9181576 DOI: 10.3390/ijms23116323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/03/2022] [Accepted: 06/04/2022] [Indexed: 12/18/2022] Open
Abstract
Glomerella leaf spot (GLS), caused by the fungus Colletotrichum fructicola, is one of the most devastating apple diseases. Our previous study reported that the GLS resistance locus was defined on the chromosome 15 region. Here, we further found a single-nucleotide polymorphism (SNP) site (SNP7309212) in the GLS resistance that was able to distinguish resistant cultivars (lines) from susceptible ones. On the basis of the SNP site, we cloned a TNL gene from the GLS resistant locus and named it MdTNL1 (NCBI Accession Number: ON402514). This gene contains a toll/interleukin-1 receptor transmembrane domain (TIR), nucleotide-binding sites (NBS), and leucine-rich repeat (LRR) domain. Subcellular location indicated that MdTNL1 was expressed in the nucleus and cell membrane. Ectopic overexpression of MdTNL1 in Nicotiana benthamiana caused cell death. We further demonstrated allelic polymorphisms in MdTNL1. It is noteworthy that NBS and LRR domains of the MdTNL1 protein serve as the repository for generating allelic diversity. Quantitative real-time PCR (qRT-PCR) assay revealed that MdTNL1 was highly expressed in resistant apple cultivar ‘Fuji’ after inoculation with C. fructicola, whereas susceptible cultivar ‘Golden Delicious’ exhibited low expression after inoculation. Over-expression of MdTNL1-1 in susceptible apple fruits and leaves improved disease resistance, while in ‘Orin’ calli, silencing the MdTNL1-1 gene conversely decreased GLS resistance. In conclusion, we identified a GLS associated with SNP7309212 and demonstrated that a TIR-NBS-LRR gene MdTNL1-1 positively regulates GLS resistance in apple.
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Andolfo G, Dohm JC, Himmelbauer H. Prediction of NB-LRR resistance genes based on full-length sequence homology. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:1592-1602. [PMID: 35365907 PMCID: PMC9322396 DOI: 10.1111/tpj.15756] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/10/2022] [Accepted: 03/29/2022] [Indexed: 05/11/2023]
Abstract
The activation of plant immunity is mediated by resistance (R)-gene receptors, also known as nucleotide-binding leucine-rich repeat (NB-LRR) genes, which in turn trigger the authentic defense response. R-gene identification is a crucial goal for both classic and modern plant breeding strategies for disease resistance. The conventional method identifies NB-LRR genes using a protein motif/domain-based search (PDS) within an automatically predicted gene set of the respective genome assembly. PDS proved to be imprecise since repeat masking prior to automatic genome annotation unwittingly prevented comprehensive NB-LRR gene detection. Furthermore, R-genes have diversified in a species-specific manner, so that NB-LRR gene identification cannot be universally standardized. Here, we present the full-length Homology-based R-gene Prediction (HRP) method for the comprehensive identification and annotation of a genome's R-gene repertoire. Our method has substantially addressed the complex genomic organization of tomato (Solanum lycopersicum) NB-LRR gene loci, proving to be more performant than the well-established RenSeq approach. HRP efficiency was also tested on three differently assembled and annotated Beta sp. genomes. Indeed, HRP identified up to 45% more full-length NB-LRR genes compared to previous approaches. HRP also turned out to be a more refined strategy for R-gene allele mining, testified by the identification of hitherto undiscovered Fom-2 homologs in five Cucurbita sp. genomes. In summary, our high-performance method for full-length NB-LRR gene discovery will propel the identification of novel R-genes towards development of improved cultivars.
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Affiliation(s)
- Giuseppe Andolfo
- Department of Agricultural SciencesUniversity of Naples ‘Federico II’Via Università 10080055Portici (Naples)Italy
| | - Juliane C. Dohm
- Institute of Computational Biology, Department of BiotechnologyUniversity of Natural Resources and Life SciencesViennaMuthgasse 181190ViennaAustria
| | - Heinz Himmelbauer
- Institute of Computational Biology, Department of BiotechnologyUniversity of Natural Resources and Life SciencesViennaMuthgasse 181190ViennaAustria
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10
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Sandell FL, Stralis-Pavese N, McGrath JM, Schulz B, Himmelbauer H, Dohm JC. Genomic distances reveal relationships of wild and cultivated beets. Nat Commun 2022; 13:2021. [PMID: 35440134 PMCID: PMC9019029 DOI: 10.1038/s41467-022-29676-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 03/28/2022] [Indexed: 12/01/2022] Open
Abstract
Cultivated beets (Beta vulgaris ssp. vulgaris), including sugar beet, rank among the most important crops. The wild ancestor of beet crops is the sea beet Beta vulgaris ssp. maritima. Species and subspecies of wild beets are readily crossable with cultivated beets and are thus available for crop improvement. To study genomic relationships in the genus Beta, we sequence and analyse 606 beet genomes, encompassing sugar beet, sea beet, B. v. adanensis, B. macrocarpa, and B. patula. We observe two genetically distinct groups of sea beets, one from the Atlantic coast and the other from the Mediterranean area. Genomic comparisons based on k-mers identify sea beets from Greece as the closest wild relatives of sugar beet, suggesting that domestication of the ancestors of sugar beet may be traced to this area. Our work provides comprehensive insight into the phylogeny of wild and cultivated beets and establishes a framework for classification of further accessions of unknown (sub-)species assignment.
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Affiliation(s)
- Felix L Sandell
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Computational Biology, Vienna, Austria
| | - Nancy Stralis-Pavese
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Computational Biology, Vienna, Austria
| | | | | | - Heinz Himmelbauer
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Computational Biology, Vienna, Austria.
| | - Juliane C Dohm
- University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Computational Biology, Vienna, Austria.
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11
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Trifonova AA, Paradnya ER, Boris KV, Kudryavtsev AM. NBS-LRR Resistance Genes Polymorphism of Sugar Beet Hybrids according to NBS-Profiling Data. RUSS J GENET+ 2022. [DOI: 10.1134/s1022795422010112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Mann L, Seibt KM, Weber B, Heitkam T. ECCsplorer: a pipeline to detect extrachromosomal circular DNA (eccDNA) from next-generation sequencing data. BMC Bioinformatics 2022; 23:40. [PMID: 35030991 PMCID: PMC8760651 DOI: 10.1186/s12859-021-04545-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/20/2021] [Indexed: 11/14/2022] Open
Abstract
Background Extrachromosomal circular DNAs (eccDNAs) are ring-like DNA structures physically separated from the chromosomes with 100 bp to several megabasepairs in size. Apart from carrying tandemly repeated DNA, eccDNAs may also harbor extra copies of genes or recently activated transposable elements. As eccDNAs occur in all eukaryotes investigated so far and likely play roles in stress, cancer, and aging, they have been prime targets in recent research—with their investigation limited by the scarcity of computational tools. Results Here, we present the ECCsplorer, a bioinformatics pipeline to detect eccDNAs in any kind of organism or tissue using next-generation sequencing techniques. Following Illumina-sequencing of amplified circular DNA (circSeq), the ECCsplorer enables an easy and automated discovery of eccDNA candidates. The data analysis encompasses two major procedures: first, read mapping to the reference genome allows the detection of informative read distributions including high coverage, discordant mapping, and split reads. Second, reference-free comparison of read clusters from amplified eccDNA against control sample data reveals specifically enriched DNA circles. Both software parts can be run separately or jointly, depending on the individual aim or data availability. To illustrate the wide applicability of our approach, we analyzed semi-artificial and published circSeq data from the model organisms Homo sapiens and Arabidopsis thaliana, and generated circSeq reads from the non-model crop plant Beta vulgaris. We clearly identified eccDNA candidates from all datasets, with and without reference genomes. The ECCsplorer pipeline specifically detected mitochondrial mini-circles and retrotransposon activation, showcasing the ECCsplorer’s sensitivity and specificity. Conclusion The ECCsplorer (available online at https://github.com/crimBubble/ECCsplorer) is a bioinformatics pipeline to detect eccDNAs in any kind of organism or tissue using next-generation sequencing data. The derived eccDNA targets are valuable for a wide range of downstream investigations—from analysis of cancer-related eccDNAs over organelle genomics to identification of active transposable elements. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04545-2.
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Affiliation(s)
- Ludwig Mann
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - Kathrin M Seibt
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - Beatrice Weber
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany
| | - Tony Heitkam
- Institute of Botany, Technische Universität Dresden, 01069, Dresden, Germany.
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13
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Galewski P, Funk A, McGrath JM. Select and Sequence of a Segregating Sugar Beet Population Provides Genomic Perspective of Host Resistance to Seedling Rhizoctonia solani Infection. FRONTIERS IN PLANT SCIENCE 2022; 12:785267. [PMID: 35095959 PMCID: PMC8793884 DOI: 10.3389/fpls.2021.785267] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/12/2021] [Indexed: 05/15/2023]
Abstract
Understanding the genetic basis of polygenic traits is a major challenge in agricultural species, especially in non-model systems. Select and sequence (SnS) experiments carried out within existing breeding programs provide a means to simultaneously identify the genomic background of a trait while improving the mean phenotype for a population. Using pooled whole genome sequencing (WGS) of selected and unselected bulks derived from a synthetic outcrossing sugar beet population EL57 (PI 663212), which segregates for seedling rhizoctonia resistance, we identified a putative genomic background involved in conditioning a resistance phenotype. Population genomic parameters were estimated to measure fixation (He), genome divergence (F ST ), and allele frequency changes between bulks (DeltaAF). We report on the genome wide patterns of variation resulting from selection and highlight specific genomic features associated with resistance. Expected heterozygosity (He) showed an increased level of fixation in the resistant bulk, indicating a greater selection pressure was applied. In total, 1,311 biallelic loci were detected as significant FST outliers (p < 0.01) in comparisons between the resistant and susceptible bulks. These loci were detected in 206 regions along the chromosomes and contained 275 genes. We estimated changes in allele frequency between bulks resulting from selection for resistance by leveraging the allele frequencies of an unselected bulk. DeltaAF was a more stringent test of selection and recovered 186 significant loci, representing 32 genes, all of which were also detected using FST. Estimates of population genetic parameters and statistical significance were visualized with respect to the EL10.2 physical map and produced a candidate gene list that was enriched for function in cell wall metabolism and plant disease resistance, including pathogen perception, signal transduction, and pathogen response. Specific variation associated with these genes was also reported and represents genetic markers for validation and prediction of resistance to Rhizoctonia. Select and sequence experiments offer a means to characterize the genetic base of sugar beet, inform selection within breeding programs, and prioritize candidate variation for functional studies.
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Affiliation(s)
- Paul Galewski
- United States Department of Agriculture – Agricultural Research Service (USDA-ARS) Northwest Irrigation and Soils Research Laboratory, Kimberly, ID, United States
- Department of Plant, Soil, and Microbial Science, Plant Breeding, Genetics, and Biotechnology Program, Michigan State University, East Lansing, MI, United States
| | - Andrew Funk
- Department of Plant, Soil, and Microbial Science, Plant Breeding, Genetics, and Biotechnology Program, Michigan State University, East Lansing, MI, United States
- United States Department of Agriculture – National Institute of Food and Agriculture (USDA-NIFA) Institute of Food Production and Sustainability, Kansas City, MO, United States
| | - J. Mitchell McGrath
- United States Department of Agriculture – Agricultural Research Service (USDA-ARS) Sugar Beet and Bean Research Unit USDA-ARS, East Lansing, MI, United States
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14
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Ravi S, Hassani M, Heidari B, Deb S, Orsini E, Li J, Richards CM, Panella LW, Srinivasan S, Campagna G, Concheri G, Squartini A, Stevanato P. Development of an SNP Assay for Marker-Assisted Selection of Soil-Borne Rhizoctonia solani AG-2-2-IIIB Resistance in Sugar Beet. BIOLOGY 2021; 11:biology11010049. [PMID: 35053047 PMCID: PMC8772932 DOI: 10.3390/biology11010049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 11/21/2022]
Abstract
Simple Summary Sustainable breeding of sugar beet against Rhizoctonia solani relies on the continuous identification of resistance genes to allow their integration into new and modern cultivars. Better control of the disease may thus be achieved by a combination of tolerant or resistant cultivars selected based on molecular markers such as SNPs. The utility of one such marker, RsBv1 (Chromosome 6, 9,000,093 bp, C/T), located in an ADP-ribosylation factor and associated with Rhizoctonia resistance resulting from validation of three geographically diverse plant materials is reported. Abstract Rhizoctonia solani, causing Rhizoctonia crown and root rot, is a major risk to sugar beet (Beta vulgaris L.) cultivation. The development of resistant varieties accelerated by marker-assisted selection is a priority of breeding programs. We report the identification of a single-nucleotide polymorphism (SNP) marker linked to Rhizoctonia resistance using restriction site-associated DNA (RAD) sequencing of two geographically discrete sets of plant materials with different degrees of resistance/susceptibility to enable a wider selection of superior genotypes. The variant calling pipeline utilized SAMtools for variant calling and the resulting raw SNPs from RAD sequencing (15,988 and 22,439 SNPs) were able to explain 13.40% and 25.45% of the phenotypic variation in the two sets of material from different sources of origin, respectively. An association analysis was carried out independently on both the datasets and mutually occurring significant SNPs were filtered depending on their contribution to the phenotype using principal component analysis (PCA) biplots. To provide a ready-to-use marker for the breeding community, a systematic molecular validation of significant SNPs distributed across the genome was undertaken to combine high-resolution melting, Sanger sequencing, and rhAmp SNP genotyping. We report that RsBv1 located on Chromosome 6 (9,000,093 bp) is significantly associated with Rhizoctonia resistance (p < 0.01) and able to explain 10% of the phenotypic disease variance. The related SNP assay is thus ready for marker-assisted selection in sugar beet breeding for Rhizoctonia resistance.
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Affiliation(s)
- Samathmika Ravi
- Department of Agronomy, Animals, Natural Resources and Environment-DAFNAE, University of Padova, 35020 Legnaro, PD, Italy; (S.R.); (S.D.); (G.C.); (A.S.)
| | - Mahdi Hassani
- Sugar Beet Seed Research Department, Hamedan Agriculture and Natural Resources Research and Education Centre, AREEO, Hamedan 65519, Iran;
| | - Bahram Heidari
- Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz 7144165186, Iran;
| | - Saptarathi Deb
- Department of Agronomy, Animals, Natural Resources and Environment-DAFNAE, University of Padova, 35020 Legnaro, PD, Italy; (S.R.); (S.D.); (G.C.); (A.S.)
| | - Elena Orsini
- Strube Research GmbH & Co. KG, 42651 Söllingen, Germany; (E.O.); (J.L.)
| | - Jinquan Li
- Strube Research GmbH & Co. KG, 42651 Söllingen, Germany; (E.O.); (J.L.)
| | - Christopher M. Richards
- USDA-ARS, National Laboratory for Genetic Resources Preservation, Fort Collins, CO 80521, USA; (C.M.R.); (L.W.P.)
| | - Lee W. Panella
- USDA-ARS, National Laboratory for Genetic Resources Preservation, Fort Collins, CO 80521, USA; (C.M.R.); (L.W.P.)
| | | | | | - Giuseppe Concheri
- Department of Agronomy, Animals, Natural Resources and Environment-DAFNAE, University of Padova, 35020 Legnaro, PD, Italy; (S.R.); (S.D.); (G.C.); (A.S.)
| | - Andrea Squartini
- Department of Agronomy, Animals, Natural Resources and Environment-DAFNAE, University of Padova, 35020 Legnaro, PD, Italy; (S.R.); (S.D.); (G.C.); (A.S.)
| | - Piergiorgio Stevanato
- Department of Agronomy, Animals, Natural Resources and Environment-DAFNAE, University of Padova, 35020 Legnaro, PD, Italy; (S.R.); (S.D.); (G.C.); (A.S.)
- Correspondence:
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15
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Hanson SJ, Dawson JC, Goldman IL. Beta vulgaris ssp. vulgaris chromosome 8 shows significant association with geosmin concentration in table beet. G3 (BETHESDA, MD.) 2021; 11:jkab344. [PMID: 34586384 PMCID: PMC8664477 DOI: 10.1093/g3journal/jkab344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 09/20/2021] [Indexed: 11/29/2022]
Abstract
Geosmin, a degraded sesquiterpene molecule with earthy and musty odor, imbues table beet with its characteristic aroma. Geosmin is heritable and endogenously produced in table beet; its earthy aroma is sought by some consumers but deters others. Geosmin biosynthesis is catalyzed by a bifunctional geosmin synthase enzyme in diverse bacteria and fungi, but a mechanism for geosmin biosynthesis in plants has not been reported. This work employed association analysis and selective genotyping of a segregating F2:3 mapping population to seek QTL associated with geosmin concentration in table beet. GBS reads were aligned to sugar beet reference genome EL10.2, and association analysis revealed two QTL for geosmin concentration on Beta vulgaris ssp. vulgaris chromosome 8. QTL at EL10.2 positions 28,017,624 and 38,488,687 each show effect size 8.7 μg·kg-1 geosmin and explain 8.5% and 6.4% of total variation in geosmin concentration, respectively. Resolution was low due to large recombination bin size and imperfect alignment between the reference genome and mapping population, but population size and selection proportion were sufficient to detect moderate to large effect QTL. This study, the first molecular genetic mapping experiment in table beet, succeeded in finding QTL for geosmin concentration in table beet, and it provides the basis for fine mapping or candidate gene investigation of functional loci for this distinctive sensory trait.
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Affiliation(s)
- Solveig J Hanson
- Centre for Sustainable Food Systems, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Julie C Dawson
- Department of Horticulture, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Irwin L Goldman
- Department of Horticulture, University of Wisconsin—Madison, Madison, WI 53706, USA
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16
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Schmidt N, Seibt KM, Weber B, Schwarzacher T, Schmidt T, Heitkam T. Broken, silent, and in hiding: tamed endogenous pararetroviruses escape elimination from the genome of sugar beet (Beta vulgaris). ANNALS OF BOTANY 2021; 128:281-299. [PMID: 33729490 PMCID: PMC8389469 DOI: 10.1093/aob/mcab042] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 03/16/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Endogenous pararetroviruses (EPRVs) are widespread components of plant genomes that originated from episomal DNA viruses of the Caulimoviridae family. Due to fragmentation and rearrangements, most EPRVs have lost their ability to replicate through reverse transcription and to initiate viral infection. Similar to the closely related retrotransposons, extant EPRVs were retained and often amplified in plant genomes for several million years. Here, we characterize the complete genomic EPRV fraction of the crop sugar beet (Beta vulgaris, Amaranthaceae) to understand how they shaped the beet genome and to suggest explanations for their absent virulence. METHODS Using next- and third-generation sequencing data and genome assembly, we reconstructed full-length in silico representatives for the three host-specific EPRVs (beetEPRVs) in the B. vulgaris genome. Focusing on the endogenous caulimovirid beetEPRV3, we investigated its chromosomal localization, abundance and distribution by fluorescent in situ and Southern hybridization. KEY RESULTS Full-length beetEPRVs range between 7.5 and 10.7 kb in size, are heterogeneous in structure and sequence, and occupy about 0.3 % of the beet genome. Although all three beetEPRVs were assigned to the florendoviruses, they showed variably arranged protein-coding domains, different fragmentation, and preferences for diverse sequence contexts. We observed small RNAs that specifically target the individual beetEPRVs, indicating stringent epigenetic suppression. BeetEPRV3 sequences occur along all sugar beet chromosomes, preferentially in the vicinity of each other and are associated with heterochromatic, centromeric and intercalary satellite DNAs. BeetEPRV3 members also exist in genomes of related wild species, indicating an initial beetEPRV3 integration 13.4-7.2 million years ago. CONCLUSIONS Our study in beet illustrates the variability of EPRV structure and sequence in a single host genome. Evidence of sequence fragmentation and epigenetic silencing implies possible plant strategies to cope with long-term persistence of EPRVs, including amplification, fixation in the heterochromatin, and containment of EPRV virulence.
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Affiliation(s)
- Nicola Schmidt
- Faculty of Biology, Institute of Botany, Technische Universität Dresden, Dresden, Germany
| | - Kathrin M Seibt
- Faculty of Biology, Institute of Botany, Technische Universität Dresden, Dresden, Germany
| | - Beatrice Weber
- Faculty of Biology, Institute of Botany, Technische Universität Dresden, Dresden, Germany
| | - Trude Schwarzacher
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization/Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou, PR China
| | - Thomas Schmidt
- Faculty of Biology, Institute of Botany, Technische Universität Dresden, Dresden, Germany
| | - Tony Heitkam
- Faculty of Biology, Institute of Botany, Technische Universität Dresden, Dresden, Germany
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17
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Hirakawa H, Toyoda A, Itoh T, Suzuki Y, Nagano AJ, Sugiyama S, Onodera Y. A spinach genome assembly with remarkable completeness, and its use for rapid identification of candidate genes for agronomic traits. DNA Res 2021; 28:6303609. [PMID: 34142133 PMCID: PMC8231376 DOI: 10.1093/dnares/dsab004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Indexed: 01/23/2023] Open
Abstract
Spinach (Spinacia oleracea) is grown as a nutritious leafy vegetable worldwide. To accelerate spinach breeding efficiency, a high-quality reference genome sequence with great completeness and continuity is needed as a basic infrastructure. Here, we used long-read and linked-read technologies to construct a de novo spinach genome assembly, designated SOL_r1.1, which was comprised of 287 scaffolds (total size: 935.7 Mb; N50 = 11.3 Mb) with a low proportion of undetermined nucleotides (Ns = 0.34%) and with high gene completeness (BUSCO complete 96.9%). A genome-wide survey of resistance gene analogues identified 695 genes encoding nucleotide-binding site domains, receptor-like protein kinases, receptor-like proteins and transmembrane-coiled coil domains. Based on a high-density double-digest restriction-site associated DNA sequencing-based linkage map, the genome assembly was anchored to six pseudomolecules representing ∼73.5% of the whole genome assembly. In addition, we used SOL_r1.1 to identify quantitative trait loci for bolting timing and fruit/seed shape, which harbour biologically plausible candidate genes, such as homologues of the FLOWERING LOCUS T and EPIDERMAL PATTERNING FACTOR-LIKE genes. The new genome assembly, SOL_r1.1, will serve as a useful resource for identifying loci associated with important agronomic traits and for developing molecular markers for spinach breeding/selection programs.
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Affiliation(s)
- Hideki Hirakawa
- The Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan
| | - Atsushi Toyoda
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima 411-8540, Japan
| | - Takehiko Itoh
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
| | - Yutaka Suzuki
- The Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8568, Japan
| | - Atsushi J Nagano
- Faculty of Agriculture, Ryukoku University, Otsu, Shiga 520-2194, Japan
| | - Suguru Sugiyama
- School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Yasuyuki Onodera
- The Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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18
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Hulse-Kemp AM, Bostan H, Chen S, Ashrafi H, Stoffel K, Sanseverino W, Li L, Cheng S, Schatz MC, Garvin T, du Toit LJ, Tseng E, Chin J, Iorizzo M, Van Deynze A. An anchored chromosome-scale genome assembly of spinach improves annotation and reveals extensive gene rearrangements in euasterids. THE PLANT GENOME 2021; 14:e20101. [PMID: 34109759 DOI: 10.1002/tpg2.20101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Spinach (Spinacia oleracea L.) is a member of the Caryophyllales family, a basal eudicot asterid that consists of sugar beet (Beta vulgaris L. subsp. vulgaris), quinoa (Chenopodium quinoa Willd.), and amaranth (Amaranthus hypochondriacus L.). With the introduction of baby leaf types, spinach has become a staple food in many homes. Production issues focus on yield, nitrogen-use efficiency and resistance to downy mildew (Peronospora effusa). Although genomes are available for the above species, a chromosome-level assembly exists only for quinoa, allowing for proper annotation and structural analyses to enhance crop improvement. We independently assembled and annotated genomes of the cultivar Viroflay using short-read strategy (Illumina) and long-read strategies (Pacific Biosciences) to develop a chromosome-level, genetically anchored assembly for spinach. Scaffold N50 for the Illumina assembly was 389 kb, whereas that for Pacific BioSciences was 4.43 Mb, representing 911 Mb (93% of the genome) in 221 scaffolds, 80% of which are anchored and oriented on a sequence-based genetic map, also described within this work. The two assemblies were 99.5% collinear. Independent annotation of the two assemblies with the same comprehensive transcriptome dataset show that the quality of the assembly directly affects the annotation with significantly more genes predicted (26,862 vs. 34,877) in the long-read assembly. Analysis of resistance genes confirms a bias in resistant gene motifs more typical of monocots. Evolutionary analysis indicates that Spinacia is a paleohexaploid with a whole-genome triplication followed by extensive gene rearrangements identified in this work. Diversity analysis of 75 lines indicate that variation in genes is ample for hypothesis-driven, genomic-assisted breeding enabled by this work.
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Affiliation(s)
- Amanda M Hulse-Kemp
- Department of Plant Sciences, University of California, Davis, CA, USA
- USDA, Agricultural Research Service, Genomics and Bioinformatics Research Unit, Raleigh, NC, USA
- Department of Crop and Soil Science, North Carolina State University, Raleigh, NC, USA
| | - Hamed Bostan
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, USA
| | - Shiyu Chen
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Hamid Ashrafi
- Department of Horticulture, North Carolina State University, Raleigh, NC, USA
| | - Kevin Stoffel
- Department of Plant Sciences, University of California, Davis, CA, USA
| | | | | | - Shifeng Cheng
- BGI-Shenzhen, Shenzhen, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518060, P. R. China
| | - Michael C Schatz
- Cold Spring Harbor Laboratory, One Bungtown Road, Koch Building 1121, Cold Spring Harbor, NY, 11724, USA
- Departments of Computer Science and Biology, Johns Hopkins University, 3400 N Charles St, Baltimore, MD, 21218, USA
| | - Tyler Garvin
- Cold Spring Harbor Laboratory, One Bungtown Road, Koch Building 1121, Cold Spring Harbor, NY, 11724, USA
| | - Lindsey J du Toit
- Washington State University, SU Mount Vernon Northwestern Washington Research & Extension Center (NWREC), Mount Vernon, WA, 98273, USA
| | | | - Jason Chin
- Pacific Biosciences, Menlo Park, CA, USA
- DNAnexus Inc, 1975 W El Camino Real #204, Mountain View, CA, 94040, USA
| | - Massimo Iorizzo
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, USA
- Department of Horticulture, North Carolina State University, Raleigh, NC, USA
| | - Allen Van Deynze
- Department of Plant Sciences, University of California, Davis, CA, USA
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19
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Lehner R, Blazek L, Minoche AE, Dohm JC, Himmelbauer H. Assembly and characterization of the genome of chard (Beta vulgaris ssp. vulgaris var. cicla). J Biotechnol 2021; 333:67-76. [PMID: 33932500 DOI: 10.1016/j.jbiotec.2021.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/09/2021] [Accepted: 04/25/2021] [Indexed: 10/21/2022]
Abstract
Chard (Beta vulgaris ssp. vulgaris var. cicla) is a member of one of four different cultigroups of beets. While the genome of sugar beet, the most prominent beet crop, has been studied extensively, molecular data on other beet cultivars is scant. Here, we present a genome assembly of chard, a vegetable crop grown for its fleshy leaves. We report a de novo genome assembly of 604 Mbp, slightly larger than sugar beet assemblies presented so far. About 57 % of the assembly was annotated as repetitive sequence, of which LTR retrotransposons were the most abundant. Based on the presence of conserved genes, the chard assembly was estimated to be at least 96 % complete regarding its gene space. We predicted 34,521 genes of which 27,582 genes were supported by evidence from transcriptomic sequencing reads, and 5503 of the evidence-supported genes had multiple isoforms. We compared the chard gene set with gene sets from sugar beet and two wild beets (i.e. Beta vulgaris ssp. maritima and Beta patula) to find orthology relationships and identified genome-wide syntenic regions between chard and sugar beet. Lastly, we determined genomic variants that distinguish sugar beet and chard. Assessing the variation distribution along the chard chromosomes, we found extensive haplotype sharing between the two cultivars. In summary, our work provides a foundation for the molecular analysis of Beta vulgaris cultigroups as a basis for chard genomics and to unravel the domestication history of beet crops.
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Affiliation(s)
- Reinhard Lehner
- Institute of Computational Biology, Department of Biotechnology, University of Life Sciences and Natural Resources, Vienna (BOKU), Muthgasse 18, 1190 Vienna, Austria
| | - Lisa Blazek
- Institute of Computational Biology, Department of Biotechnology, University of Life Sciences and Natural Resources, Vienna (BOKU), Muthgasse 18, 1190 Vienna, Austria
| | - André E Minoche
- Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia
| | - Juliane C Dohm
- Institute of Computational Biology, Department of Biotechnology, University of Life Sciences and Natural Resources, Vienna (BOKU), Muthgasse 18, 1190 Vienna, Austria.
| | - Heinz Himmelbauer
- Institute of Computational Biology, Department of Biotechnology, University of Life Sciences and Natural Resources, Vienna (BOKU), Muthgasse 18, 1190 Vienna, Austria.
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20
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Chen X, Tong C, Zhang X, Song A, Hu M, Dong W, Chen F, Wang Y, Tu J, Liu S, Tang H, Zhang L. A high-quality Brassica napus genome reveals expansion of transposable elements, subgenome evolution and disease resistance. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:615-630. [PMID: 33073445 PMCID: PMC7955885 DOI: 10.1111/pbi.13493] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 09/21/2020] [Accepted: 10/13/2020] [Indexed: 05/03/2023]
Abstract
Rapeseed (Brassica napus L.) is a recent allotetraploid crop, which is well known for its high oil production. Here, we report a high-quality genome assembly of a typical semi-winter rapeseed cultivar, 'Zhongshuang11' (hereafter 'ZS11'), using a combination of single-molecule sequencing and chromosome conformation capture (Hi-C) techniques. Most of the high-confidence sequences (93.1%) were anchored to the individual chromosomes with a total of 19 centromeres identified, matching the exact chromosome count of B. napus. The repeat sequences in the A and C subgenomes in B. napus expanded significantly from 500 000 years ago, especially over the last 100 000 years. These young and recently amplified LTR-RTs showed dispersed chromosomal distribution but significantly preferentially clustered into centromeric regions. We exhaustively annotated the nucleotide-binding leucine-rich repeat (NLR) gene repertoire, yielding a total of 597 NLR genes in B. napus genome and 17.4% of which are paired (head-to-head arrangement). Based on the resequencing data of 991 B. napus accessions, we have identified 18 759 245 single nucleotide polymorphisms (SNPs) and detected a large number of genomic regions under selective sweep among the three major ecotype groups (winter, semi-winter and spring) in B. napus. We found 49 NLR genes and five NLR gene pairs colocated in selective sweep regions with different ecotypes, suggesting a rapid diversification of NLR genes during the domestication of B. napus. The high quality of our B. napus 'ZS11' genome assembly could serve as an important resource for the study of rapeseed genomics and reveal the genetic variations associated with important agronomic traits.
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Affiliation(s)
- Xuequn Chen
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems BiologyKey Laboratory of Ministry of Education for Genetics & Breeding and Multiple Utilization of CropsCollege of AgricultureFujian Agriculture and Forestry UniversityFuzhouChina
| | - Chaobo Tong
- The Key Laboratory of Biology and Genetic Improvement of Oil CropsThe Ministry of Agriculture and Rural Affairs of PRCOil Crops Research InstituteChinese Academy of Agricultural SciencesWuhanChina
| | - Xingtan Zhang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems BiologyKey Laboratory of Ministry of Education for Genetics & Breeding and Multiple Utilization of CropsCollege of AgricultureFujian Agriculture and Forestry UniversityFuzhouChina
| | - Aixia Song
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems BiologyKey Laboratory of Ministry of Education for Genetics & Breeding and Multiple Utilization of CropsCollege of AgricultureFujian Agriculture and Forestry UniversityFuzhouChina
| | - Ming Hu
- The Key Laboratory of Biology and Genetic Improvement of Oil CropsThe Ministry of Agriculture and Rural Affairs of PRCOil Crops Research InstituteChinese Academy of Agricultural SciencesWuhanChina
| | - Wei Dong
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems BiologyKey Laboratory of Ministry of Education for Genetics & Breeding and Multiple Utilization of CropsCollege of AgricultureFujian Agriculture and Forestry UniversityFuzhouChina
| | - Fei Chen
- College of HorticultureNanjing Agricultural UniversityNanjingChina
| | - Youping Wang
- Key Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Jinxing Tu
- National Key Laboratory of Crop Genetic ImprovementNational Center of Rapeseed ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Shengyi Liu
- The Key Laboratory of Biology and Genetic Improvement of Oil CropsThe Ministry of Agriculture and Rural Affairs of PRCOil Crops Research InstituteChinese Academy of Agricultural SciencesWuhanChina
| | - Haibao Tang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems BiologyKey Laboratory of Ministry of Education for Genetics & Breeding and Multiple Utilization of CropsCollege of AgricultureFujian Agriculture and Forestry UniversityFuzhouChina
| | - Liangsheng Zhang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems BiologyKey Laboratory of Ministry of Education for Genetics & Breeding and Multiple Utilization of CropsCollege of AgricultureFujian Agriculture and Forestry UniversityFuzhouChina
- Genomics and Genetic Engineering Laboratory of Ornamental PlantsCollege of Agriculture and BiotechnologyZhejiang UniversityHangzhouChina
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21
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Holmquist L, Dölfors F, Fogelqvist J, Cohn J, Kraft T, Dixelius C. Major latex protein-like encoding genes contribute to Rhizoctonia solani defense responses in sugar beet. Mol Genet Genomics 2020; 296:155-164. [PMID: 33118051 PMCID: PMC7840631 DOI: 10.1007/s00438-020-01735-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/09/2020] [Indexed: 12/15/2022]
Abstract
Sugar beets are attacked by several pathogens that cause root damages. Rhizoctonia (Greek for “root killer”) is one of them. Rhizoctonia root rot has become an increasing problem for sugar beet production and to decrease yield losses agronomical measures are adopted. Here, two partially resistant and two susceptible sugar beet genotypes were used for transcriptome analysis to discover new defense genes to this fungal disease, information to be implemented in molecular resistance breeding. Among 217 transcripts with increased expression at 2 days post-infection (dpi), three resistance-like genes were found. These genes were not significantly elevated at 5 dpi, a time point when increased expression of three Bet v I/Major latex protein (MLP) homologous genes BvMLP1, BvMLP2 and BvML3 was observed in the partially resistant genotypes. Quantitative RT-PCR analysis on diseased sugar beet seedlings validated the activity of BvMLP1 and BvMLP3 observed in the transcriptome during challenge by R. solani. The three BvMLP genes were cloned and overexpressed in Arabidopsis thaliana to further dissect their individual contribution. Transgenic plants were also compared to T-DNA mutants of orthologous MLP genes. Plants overexpressing BvMLP1 and BvMLP3 showed significantly less infection whereas additive effects were seen on Atmlp1/Atmlp3 double mutants. The data suggest that BvMLP1 and BvMLP3 may contribute to the reduction of the Rhizoctonia root rot disease in sugar beet. Impact on the defense reaction from other differential expressed genes observed in the study is discussed.
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Affiliation(s)
- Louise Holmquist
- MariboHilleshög Research AB, Säbyholmsvägen 24, 26191, Landskrona, Sweden.,Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden
| | - Fredrik Dölfors
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden
| | - Johan Fogelqvist
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden
| | - Jonathan Cohn
- Syngenta, Crop Protection, 9 Davis Drive, Research Triangle Park, NC, 27709, USA
| | - Thomas Kraft
- MariboHilleshög Research AB, Säbyholmsvägen 24, 26191, Landskrona, Sweden
| | - Christina Dixelius
- Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007, Uppsala, Sweden.
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22
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Rangel LI, Spanner RE, Ebert MK, Pethybridge SJ, Stukenbrock EH, de Jonge R, Secor GA, Bolton MD. Cercospora beticola: The intoxicating lifestyle of the leaf spot pathogen of sugar beet. MOLECULAR PLANT PATHOLOGY 2020; 21:1020-1041. [PMID: 32681599 PMCID: PMC7368123 DOI: 10.1111/mpp.12962] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/15/2020] [Accepted: 05/17/2020] [Indexed: 05/07/2023]
Abstract
Cercospora leaf spot, caused by the fungal pathogen Cercospora beticola, is the most destructive foliar disease of sugar beet worldwide. This review discusses C. beticola genetics, genomics, and biology and summarizes our current understanding of the molecular interactions that occur between C. beticola and its sugar beet host. We highlight the known virulence arsenal of C. beticola as well as its ability to overcome currently used disease management strategies. Finally, we discuss future prospects for the study and management of C. beticola infections in the context of newly employed molecular tools to uncover additional information regarding the biology of this pathogen. TAXONOMY Cercospora beticola Sacc.; Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Capnodiales, Family Mycosphaerellaceae, Genus Cercospora. HOST RANGE Well-known pathogen of sugar beet (Beta vulgaris subsp. vulgaris) and most species of the Beta genus. Reported as pathogenic on other members of the Chenopodiaceae (e.g., lamb's quarters, spinach) as well as members of the Acanthaceae (e.g., bear's breeches), Apiaceae (e.g., Apium), Asteraceae (e.g., chrysanthemum, lettuce, safflower), Brassicaceae (e.g., wild mustard), Malvaceae (e.g., Malva), Plumbaginaceae (e.g., Limonium), and Polygonaceae (e.g., broad-leaved dock) families. DISEASE SYMPTOMS Leaves infected with C. beticola exhibit circular lesions that are coloured tan to grey in the centre and are often delimited by tan-brown to reddish-purple rings. As disease progresses, spots can coalesce to form larger necrotic areas, causing severely infected leaves to wither and die. At the centre of these spots are black spore-bearing structures (pseudostromata). Older leaves often show symptoms first and younger leaves become infected as the disease progresses. MANAGEMENT Application of a mixture of fungicides with different modes of action is currently performed although elevated resistance has been documented in most employed fungicide classes. Breeding for high-yielding cultivars with improved host resistance is an ongoing effort and prudent cultural practices, such as crop rotation, weed host management, and cultivation to reduce infested residue levels, are widely used to manage disease. USEFUL WEBSITE: https://www.ncbi.nlm.nih.gov/genome/11237?genome_assembly_id=352037.
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Affiliation(s)
- Lorena I. Rangel
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
| | - Rebecca E. Spanner
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
| | - Malaika K. Ebert
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
- Present address:
Department of Plant BiologyMichigan State UniversityEast LansingMIUSA
| | - Sarah J. Pethybridge
- Plant Pathology & Plant‐Microbe Biology SectionSchool of Integrative Plant ScienceCornell AgriTech at The New York State Agricultural Experiment StationCornell UniversityGenevaNYUSA
| | - Eva H. Stukenbrock
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Christian‐Albrechts University of KielKielGermany
| | - Ronnie de Jonge
- Department of Plant‐Microbe InteractionsUtrecht UniversityUtrechtNetherlands
| | - Gary A. Secor
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
| | - Melvin D. Bolton
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
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23
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Hunt SP, Jarvis DE, Larsen DJ, Mosyakin SL, Kolano BA, Jackson EW, Martin SL, Jellen EN, Maughan PJ. A Chromosome-Scale Assembly of the Garden Orach ( Atriplex hortensis L.) Genome Using Oxford Nanopore Sequencing. FRONTIERS IN PLANT SCIENCE 2020; 11:624. [PMID: 32523593 PMCID: PMC7261831 DOI: 10.3389/fpls.2020.00624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/22/2020] [Indexed: 05/16/2023]
Abstract
Atriplex hortensis (2n = 2x = 18, 1C genome size ∼1.1 gigabases), also known as garden orach and mountain-spinach, is a highly nutritious, broadleaf annual of the Amaranthaceae-Chenopodiaceae alliance (Chenopodiaceae sensu stricto, subfam. Chenopodioideae) that has spread in cultivation from its native primary domestication area in Eurasia to other temperate and subtropical regions worldwide. Atriplex L. is a highly complex but, as understood now, a monophyletic group of mainly halophytic and/or xerophytic plants, of which A. hortensis has been a vegetable of minor importance in some areas of Eurasia (from Central Asia to the Mediterranean) at least since antiquity. Nonetheless, it is a crop with tremendous nutritional potential due primarily to its exceptional leaf and seed protein quantities (approaching 30%) and quality (high levels of lysine). Although there is some literature describing the taxonomy and production of A. hortensis, there is a general lack of genetic and genomic data that would otherwise help elucidate the genetic variation, phylogenetic positioning, and future potential of the species. Here, we report the assembly of the first high-quality, chromosome-scale reference genome for A. hortensis cv. "Golden." Long-read data from Oxford Nanopore's MinION DNA sequencer was assembled with the program Canu and polished with Illumina short reads. Contigs were scaffolded to chromosome scale using chromatin-proximity maps (Hi-C) yielding a final assembly containing 1,325 scaffolds with a N50 of 98.9 Mb - with 94.7% of the assembly represented in the nine largest, chromosome-scale scaffolds. Sixty-six percent of the genome was classified as highly repetitive DNA, with the most common repetitive elements being Gypsy-(32%) and Copia-like (11%) long-terminal repeats. The annotation was completed using MAKER which identified 37,083 gene models and 2,555 tRNA genes. Completeness of the genome, assessed using the Benchmarking Universal Single Copy Orthologs (BUSCO) metric, identified 97.5% of the conserved orthologs as complete, with only 2.2% being duplicated, reflecting the diploid nature of A. hortensis. A resequencing panel of 21 wild, unimproved and cultivated A. hortensis accessions revealed three distinct populations with little variation within subpopulations. These resources provide vital information to better understand A. hortensis and facilitate future study.
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Affiliation(s)
- Spencer P. Hunt
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, United States
| | - David E. Jarvis
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, United States
| | - Dallas J. Larsen
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, United States
| | - Sergei L. Mosyakin
- M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Bozena A. Kolano
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | | | - Sara L. Martin
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
| | - Eric N. Jellen
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, United States
| | - Peter J. Maughan
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT, United States
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24
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Lunardon A, Johnson NR, Hagerott E, Phifer T, Polydore S, Coruh C, Axtell MJ. Integrated annotations and analyses of small RNA-producing loci from 47 diverse plants. Genome Res 2020; 30:497-513. [PMID: 32179590 PMCID: PMC7111516 DOI: 10.1101/gr.256750.119] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/27/2020] [Indexed: 01/25/2023]
Abstract
Plant endogenous small RNAs (sRNAs) are important regulators of gene expression. There are two broad categories of plant sRNAs: microRNAs (miRNAs) and endogenous short interfering RNAs (siRNAs). MicroRNA loci are relatively well-annotated but compose only a small minority of the total sRNA pool; siRNA locus annotations have lagged far behind. Here, we used a large data set of published and newly generated sRNA sequencing data (1333 sRNA-seq libraries containing more than 20 billion reads) and a uniform bioinformatic pipeline to produce comprehensive sRNA locus annotations of 47 diverse plants, yielding more than 2.7 million sRNA loci. The two most numerous classes of siRNA loci produced mainly 24- and 21-nucleotide (nt) siRNAs, respectively. Most often, 24-nt-dominated siRNA loci occurred in intergenic regions, especially at the 5′-flanking regions of protein-coding genes. In contrast, 21-nt-dominated siRNA loci were most often derived from double-stranded RNA precursors copied from spliced mRNAs. Genic 21-nt-dominated loci were especially common from disease resistance genes, including from a large number of monocots. Individual siRNA sequences of all types showed very little conservation across species, whereas mature miRNAs were more likely to be conserved. We developed a web server where our data and several search and analysis tools are freely accessible.
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Affiliation(s)
- Alice Lunardon
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Nathan R Johnson
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Emily Hagerott
- Department of Biology, Knox College, Galesburg, Illinois 61401, USA
| | - Tamia Phifer
- Department of Biology, Knox College, Galesburg, Illinois 61401, USA
| | - Seth Polydore
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Ceyda Coruh
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Michael J Axtell
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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25
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Galewski P, McGrath JM. Genetic diversity among cultivated beets (Beta vulgaris) assessed via population-based whole genome sequences. BMC Genomics 2020; 21:189. [PMID: 32122300 PMCID: PMC7053042 DOI: 10.1186/s12864-020-6451-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/03/2020] [Indexed: 12/14/2022] Open
Abstract
Background Diversification on the basis of utilization is a hallmark of Beta vulgaris (beet), as well as other crop species. Often, crop improvement and management activities are segregated by crop type, thus preserving unique genome diversity and organization. Full interfertility is typically retained in crosses between these groups and more traits may be accessible if the genetic basis of crop type lineage were known, along with available genetic markers to effect efficient transfer (e.g., via backcrossing). Beta vulgaris L. (2n =18) is a species complex composed of diverged lineages (e.g., crop types), including the familiar table, leaf (chard), fodder, and sugar beet crop types. Using population genetic and statistical methods with whole genome sequence data from pooled samples of 23 beet cultivars and breeding lines, relationships were determined between accessions based on identity-by-state metrics and shared genetic variation among lineages. Results Distribution of genetic variation within and between crop types showed extensive shared (e.g. non-unique) genetic variation. Lineage specific variation (e.g. apomorphy) within crop types supported a shared demographic history within each crop type, while principal components analysis revealed strong crop type differentiation. Relative contributions of specific chromosomes to genome wide differentiation were ascertained, with each chromosome revealing a different pattern of differentiation with respect to crop type. Inferred population size history for each crop type helped integrate selection history for each lineage, and highlighted potential genetic bottlenecks in the development of cultivated beet lineages. Conclusions A complex evolutionary history of cultigroups in Beta vulgaris was demonstrated, involving lineage divergence as a result of selection and reproductive isolation. Clear delineation of crop types was obfuscated by historical gene flow and common ancestry (e.g. admixture and introgression, and sorting of ancestral polymorphism) which served to share genome variation between crop types and, likely, important phenotypic characters. Table beet was well differentiated as a crop type, and shared more genetic variation within than among crop types. The sugar beet group was not quite as well differentiated as the table beet group. Fodder and chard groups were intermediate between table and sugar groups, perhaps the result of less intensive selection for end use.
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Affiliation(s)
- Paul Galewski
- Department of Plant, Soil, and Microbial Science, Plant Breeding, Genetics, and Biotechnology Program, Michigan State University, 1066 Bogue Street, East Lansing, MI, 48824, USA.
| | - J Mitchell McGrath
- USDA-ARS, Sugarbeet and Bean Research Unit, 1066 Bogue Street, 494 PSSB, East Lansing, MI, 48824, USA
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26
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Arakawa T, Sugaya H, Katsuyama T, Honma Y, Matsui K, Matsuhira H, Kuroda Y, Kitazaki K, Kubo T. How did a duplicated gene copy evolve into a restorer-of-fertility gene in a plant? The case of Oma1. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190853. [PMID: 31827833 PMCID: PMC6894571 DOI: 10.1098/rsos.190853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 10/08/2019] [Indexed: 05/24/2023]
Abstract
Restorer-of-fertility (Rf) is a suppressor of cytoplasmic male sterility (CMS), a mitochondrion-encoded trait that has been reported in many plant species. The occurrence of CMS is considered to be independent in each lineage; hence, the question of how Rf evolved was raised. Sugar beet Rf resembles Oma1, a gene for quality control of the mitochondrial inner membrane. Oma1 homologues comprise a small gene family in the sugar beet genome, unlike Arabidopsis and other eukaryotes. The sugar beet sequence that best matched Arabidopsis atOma1 was named bvOma1; sugar beet Rf (RF1-Oma1) was another member. During anther development, atOma1 mRNA was detected from the tetrad to the microspore stages, whereas bvOma1 mRNA was detected at the microspore stage and RF1-Oma1 mRNA was detected during the meiosis and tetrad stages. A transgenic study revealed that, whereas RF1-Oma1 can bind to a CMS-specific protein and alter the higher-order structure of the CMS-specific protein complex, neither bvOma1 nor atOma1 show such activity. We favour the hypothesis that an ancestral Oma1 gene duplicated to form a small gene family, and that one of the copies evolved and acquired a novel expression pattern and protein function as an Rf, i.e. RF1-Oma1 evolved via neofunctionalization.
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Affiliation(s)
- Takumi Arakawa
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Hajime Sugaya
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Takaya Katsuyama
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Yujiro Honma
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
- Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, Kitami, Hokkaido 090-8507, Japan
| | - Katsunori Matsui
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Hiroaki Matsuhira
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Memuro, Hokkaido 082-0081, Japan
| | - Yosuke Kuroda
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Memuro, Hokkaido 082-0081, Japan
| | - Kazuyoshi Kitazaki
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Tomohiko Kubo
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
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27
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Mangelson H, Jarvis DE, Mollinedo P, Rollano‐Penaloza OM, Palma‐Encinas VD, Gomez‐Pando LR, Jellen EN, Maughan PJ. The genome of Chenopodium pallidicaule: An emerging Andean super grain. APPLICATIONS IN PLANT SCIENCES 2019; 7:e11300. [PMID: 31832282 PMCID: PMC6858295 DOI: 10.1002/aps3.11300] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/24/2019] [Indexed: 05/28/2023]
Abstract
PREMISE Cañahua is a semi-domesticated crop grown in high-altitude regions of the Andes. It is an A-genome diploid (2n = 2x = 18) relative of the allotetraploid (AABB) Chenopodium quinoa and shares many of its nutritional benefits. Cañahua seed contains a complete protein, a low glycemic index, and offers a wide variety of nutritionally important vitamins and minerals. METHODS The reference assembly was developed using a combination of short- and long-read sequencing techniques, including multiple rounds of Hi-C-based proximity-guided assembly. RESULTS The final assembly of the ~363-Mbp genome consists of 4633 scaffolds, with 96.6% of the assembly contained in nine scaffolds representing the nine haploid chromosomes of the species. Repetitive element analysis classified 52.3% of the assembly as repetitive, with the most common repeat identified as long terminal repeat retrotransposons. MAKER annotation of the final assembly yielded 22,832 putative gene models. DISCUSSION When compared with quinoa, strong patterns of synteny support the hypothesis that cañahua is a close A-genome diploid relative, and thus potentially a simplified model diploid species for genetic analysis and improvement of quinoa. Resequencing and phylogenetic analysis of a diversity panel of cañahua accessions suggests that coordinated efforts are needed to enhance genetic diversity conservation within ex situ germplasm collections.
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Affiliation(s)
- Hayley Mangelson
- Department of Plant and Wildlife SciencesBrigham Young University5144 LSBProvoUtah84602USA
| | - David E. Jarvis
- Department of Plant and Wildlife SciencesBrigham Young University5144 LSBProvoUtah84602USA
| | - Patricia Mollinedo
- Institute of Natural Product ResearchUniversidad Mayor de San AndrésLa PazBolivia
| | | | | | - Luz Rayda Gomez‐Pando
- Departamento de FitotecniaFacultad de AgronomíaUniversidad Nacional Agraria de La MolinaLa MolinaPeru
| | - Eric N. Jellen
- Department of Plant and Wildlife SciencesBrigham Young University5144 LSBProvoUtah84602USA
| | - Peter J. Maughan
- Department of Plant and Wildlife SciencesBrigham Young University5144 LSBProvoUtah84602USA
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Abstract
Octoploid strawberry (Fragaria ×ananassa) is a valuable specialty crop, but profitable production and availability are threatened by many pathogens. Efforts to identify and introgress useful disease resistance genes (R-genes) in breeding programs are complicated by strawberry’s complex octoploid genome. Recently-developed resources in strawberry, including a complete octoploid reference genome and high-resolution octoploid genotyping, enable new analyses in strawberry disease resistance genetics. This study characterizes the complete R-gene collection in the genomes of commercial octoploid strawberry and two diploid ancestral relatives, and introduces several new technological and data resources for strawberry disease resistance research. These include octoploid R-gene transcription profiling, dN/dS analysis, expression quantitative trait loci (eQTL) analysis and RenSeq analysis in cultivars. Octoploid fruit eQTL were identified for 76 putative R-genes. R-genes from the ancestral diploids Fragaria vesca and Fragaria iinumae were compared, revealing differential inheritance and retention of various octoploid R-gene subtypes. The mode and magnitude of natural selection of individual F. ×ananassa R-genes was also determined via dN/dS analysis. R-gene sequencing using enriched libraries (RenSeq) has been used recently for R-gene discovery in many crops, however this technique somewhat relies upon a priori knowledge of desired sequences. An octoploid strawberry capture-probe panel, derived from the results of this study, is validated in a RenSeq experiment and is presented for community use. These results give unprecedented insight into crop disease resistance genetics, and represent an advance toward exploiting variation for strawberry cultivar improvement.
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Rodríguez del Río Á, Minoche AE, Zwickl NF, Friedrich A, Liedtke S, Schmidt T, Himmelbauer H, Dohm JC. Genomes of the wild beets Beta patula and Beta vulgaris ssp. maritima. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:1242-1253. [PMID: 31104348 PMCID: PMC9546096 DOI: 10.1111/tpj.14413] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/23/2019] [Accepted: 05/02/2019] [Indexed: 05/04/2023]
Abstract
We present draft genome assemblies of Beta patula, a critically endangered wild beet endemic to the Madeira archipelago, and of the closely related Beta vulgaris ssp. maritima (sea beet). Evidence-based reference gene sets for B. patula and sea beet were generated, consisting of 25 127 and 27 662 genes, respectively. The genomes and gene sets of the two wild beets were compared with their cultivated sister taxon B. vulgaris ssp. vulgaris (sugar beet). Large syntenic regions were identified, and a display tool for automatic genome-wide synteny image generation was developed. Phylogenetic analysis based on 9861 genes showing 1:1:1 orthology supported the close relationship of B. patula to sea beet and sugar beet. A comparative analysis of the Rz2 locus, responsible for rhizomania resistance, suggested that the sequenced B. patula accession was rhizomania susceptible. Reference karyotypes for the two wild beets were established, and genomic rearrangements were detected. We consider our data as highly valuable and comprehensive resources for wild beet studies, B. patula conservation management, and sugar beet breeding research.
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Affiliation(s)
- Álvaro Rodríguez del Río
- University of Natural Resources and Life Sciences (BOKU)1190ViennaAustria
- Present address:
Centro de Biotecnología y Genómica de PlantasUPM – INIA28223MadridSpain
| | - André E. Minoche
- Garvan Institute of Medical ResearchDarlinghurst2010NSWAustralia
| | - Nikolaus F. Zwickl
- University of Natural Resources and Life Sciences (BOKU)1190ViennaAustria
| | - Anja Friedrich
- University of Natural Resources and Life Sciences (BOKU)1190ViennaAustria
- Present address:
FH Campus WienUniversity of Applied Sciences1030ViennaAustria
| | | | | | - Heinz Himmelbauer
- University of Natural Resources and Life Sciences (BOKU)1190ViennaAustria
| | - Juliane C. Dohm
- University of Natural Resources and Life Sciences (BOKU)1190ViennaAustria
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30
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Genome-wide identification, characterization, and expression analysis of nucleotide-binding leucine-rich repeats gene family under environmental stresses in tea (Camellia sinensis). Genomics 2019; 112:1351-1362. [PMID: 31408701 DOI: 10.1016/j.ygeno.2019.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/25/2019] [Accepted: 08/09/2019] [Indexed: 12/28/2022]
Abstract
Plants often use nucleotide-binding leucine-rich repeats (NLRs) to recognize specific virulence proteins and activate the hypersensitive response thereby defending against invaders. However, data on NLRs and the resistance mechanism of NLR protein mediation in tea plant are extremely limited. In this study, 400 and 303 CsNLRs were identified from the genomes of C. sinensis var. sinensis (CSS) and C. sinensis var. assamica (CSA), respectively. Phylogenetic analysis revealed that the numbers in CNL groups are predominant in both CSS and CSA. RNA-Seq revealed that the expression of CsNLRs is induced by Colletotrichum fructicola, cold, drought, salt stress and exogenous methyl jasmonate. The 21 CsCNLs that are highly expressed in tea plant under biotic and abiotic stresses as well as during bud dormancy and in different tissues are identified. Gene structure analysis revealed several cis-regulatory elements associated with phytohormones and light responsiveness in the promoter regions of these 21 CsCNLs.
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31
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Wu Z, Li M, Dong OX, Xia S, Liang W, Bao Y, Wasteneys G, Li X. Differential regulation of TNL-mediated immune signaling by redundant helper CNLs. THE NEW PHYTOLOGIST 2019; 222:938-953. [PMID: 30585636 DOI: 10.1111/nph.15665] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/23/2018] [Indexed: 05/09/2023]
Abstract
Higher plants utilize nucleotide-binding leucine-rich repeat domain proteins (NLRs) as intracellular immune receptors to recognize pathogen-derived effectors and trigger a robust defense. The Activated Disease Resistance 1 (ADR1) family of coiled-coil NLRs (CNLs) have evolved as helper NLRs that function downstream of many TIR-type sensor NLRs (TNLs). Close homologs of ADR1s form the N REQUIREMENT GENE 1 (NRG1) family in Arabidopsis, the function of which is unclear. Through CRISPR/Cas9 gene editing methods, we discovered that the tandemly repeated NRG1A and NRG1B are functionally redundant and operate downstream of TNLs with differential strengths. Interestingly, ADR1s and NRG1s function in two distinct parallel pathways contributing to TNL-specific immunity. Synergistic effects on basal and TNL-mediated defense were detected among ADR1s and NRG1s. An intact P-loop of NRG1s is not required for mediating signals from sensor TNLs, whereas auto-active NRG1A exhibits autoimmunity. Importantly, NRG1s localize to the cytosol and endomembrane network regardless of the presence of effectors, suggesting a cytosolic activation mechanism. Taken together, different sensor TNLs differentially use two groups of helper NLRs, ADR1s and NRG1s, to transduce downstream defense signals.
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Affiliation(s)
- Zhongshou Wu
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Meng Li
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Oliver Xiaoou Dong
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Shitou Xia
- Hunan Provincial Key Laboratory of Phytohormones, Hunan Agricultural University, Changsha, 410128, China
| | - Wanwan Liang
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Yongkang Bao
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Geoffrey Wasteneys
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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