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Rossato M, Marcolungo L, De Antoni L, Lopatriello G, Bellucci E, Cortinovis G, Frascarelli G, Nanni L, Bitocchi E, Di Vittori V, Vincenzi L, Lucchini F, Bett KE, Ramsay L, Konkin DJ, Delledonne M, Papa R. CRISPR-Cas9-based repeat depletion for high-throughput genotyping of complex plant genomes. Genome Res 2023; 33:787-797. [PMID: 37127332 PMCID: PMC10317117 DOI: 10.1101/gr.277628.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/26/2023] [Indexed: 05/03/2023]
Abstract
High-throughput genotyping enables the large-scale analysis of genetic diversity in population genomics and genome-wide association studies that combine the genotypic and phenotypic characterization of large collections of accessions. Sequencing-based approaches for genotyping are progressively replacing traditional genotyping methods because of the lower ascertainment bias. However, genome-wide genotyping based on sequencing becomes expensive in species with large genomes and a high proportion of repetitive DNA. Here we describe the use of CRISPR-Cas9 technology to deplete repetitive elements in the 3.76-Gb genome of lentil (Lens culinaris), 84% consisting of repeats, thus concentrating the sequencing data on coding and regulatory regions (single-copy regions). We designed a custom set of 566,766 gRNAs targeting 2.9 Gbp of repeats and excluding repetitive regions overlapping annotated genes and putative regulatory elements based on ATAC-seq data. The novel depletion method removed ∼40% of reads mapping to repeats, increasing those mapping to single-copy regions by ∼2.6-fold. When analyzing 25 million fragments, this repeat-to-single-copy shift in the sequencing data increased the number of genotyped bases of ∼10-fold compared to nondepleted libraries. In the same condition, we were also able to identify ∼12-fold more genetic variants in the single-copy regions and increased the genotyping accuracy by rescuing thousands of heterozygous variants that otherwise would be missed because of low coverage. The method performed similarly regardless of the multiplexing level, type of library or genotypes, including different cultivars and a closely related species (L. orientalis). Our results showed that CRISPR-Cas9-driven repeat depletion focuses sequencing data on single-copy regions, thus improving high-density and genome-wide genotyping in large and repetitive genomes.
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Affiliation(s)
- Marzia Rossato
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
- Genartis s.r.l., 37126 Verona, Italy
| | - Luca Marcolungo
- Department of Biotechnology, University of Verona, 37134 Verona, Italy
| | - Luca De Antoni
- Department of Biotechnology, University of Verona, 37134 Verona, Italy
| | | | - Elisa Bellucci
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Gaia Cortinovis
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Giulia Frascarelli
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Laura Nanni
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Elena Bitocchi
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Valerio Di Vittori
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy
| | - Leonardo Vincenzi
- Department of Biotechnology, University of Verona, 37134 Verona, Italy
| | - Filippo Lucchini
- Department of Biotechnology, University of Verona, 37134 Verona, Italy
| | - Kirstin E Bett
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada
| | - Larissa Ramsay
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada
| | | | - Massimo Delledonne
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
- Genartis s.r.l., 37126 Verona, Italy
| | - Roberto Papa
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, 60131 Ancona, Italy;
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Hashimoto K, Kazama Y, Ichida H, Abe T, Murai K. Einkorn Wheat ( Triticum monococcum) Mutant Extra-Early Flowering 4, Generated by Heavy-Ion Beam Irradiation, Has a Deletion of the LIGHT-REGULATED WD1 Homolog. CYTOLOGIA 2021. [DOI: 10.1508/cytologia.86.297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Yusuke Kazama
- Graduate School of Bioscience, Fukui Prefectural University
| | | | - Tomoko Abe
- RIKEN, Nishina Center for Accelerator-Based Science
| | - Koji Murai
- Graduate School of Bioscience, Fukui Prefectural University
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Guerra-García A, Gioia T, von Wettberg E, Logozzo G, Papa R, Bitocchi E, Bett KE. Intelligent Characterization of Lentil Genetic Resources: Evolutionary History, Genetic Diversity of Germplasm, and the Need for Well-Represented Collections. Curr Protoc 2021; 1:e134. [PMID: 34004055 DOI: 10.1002/cpz1.134] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The genetic and phenotypic characterization of crops allows us to elucidate their evolutionary and domestication history, the genetic basis of important traits, and the use of variation present in landraces and wild relatives to enhance resilience. In this context, we aim to provide an overview of the main genetic resources developed for lentil and their main outcomes, and to suggest protocols for continued work on this important crop. Lens culinaris is the third-most-important cool-season grain and its use is increasing as a quick-cooking, nutritious, plant-based source of protein. L. culinaris was domesticated in the Fertile Crescent, and six additional wild taxa (L. orientalis, L. tomentosus, L. odemensis, L. lamottei, L. ervoides, and L. nigricans) are recognized. Numerous genetic diversity studies have shown that wild relatives present high levels of genetic variation and provide a reservoir of alleles that can be used for breeding programs. Furthermore, the integration of genetics/genomics and breeding techniques has resulted in identification of quantitative trait loci and genes related to attributes of interest. Genetic maps, massive genotyping, marker-assisted selection, and genomic selection are some of the genetic resources generated and applied in lentil. In addition, despite its size (∼4 Gbp) and complexity, the L. culinaris genome has been assembled, allowing a deeper understanding of its architecture. Still, major knowledge gaps exist in lentil, and a deeper understanding and characterization of germplasm resources, including wild relatives, is critical to lentil breeding and improvement. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Recording of lentil seed descriptors Basic Protocol 2: Lentil seed imaging Basic Protocol 3: Lentil seed increase Basic Protocol 4: Recording of primary lentil seed INCREASE descriptors.
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Affiliation(s)
- Azalea Guerra-García
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Tania Gioia
- School of Agriculture, Forestry, Food and Environmental Sciences, University of Basilicata, Potenza, Italy
| | - Eric von Wettberg
- Department of Plant and Soil Sciences and Gund Institute for the Environment, University of Vermont, Burlington, Vermont
| | - Giuseppina Logozzo
- School of Agriculture, Forestry, Food and Environmental Sciences, University of Basilicata, Potenza, Italy
| | - Roberto Papa
- Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Ancona, Italy
| | - Elena Bitocchi
- Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Ancona, Italy
| | - Kirstin E Bett
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Udagawa H, Ichida H, Takeuchi T, Abe T, Takakura Y. Highly Efficient and Comprehensive Identification of Ethyl Methanesulfonate-Induced Mutations in Nicotiana tabacum L. by Whole-Genome and Whole-Exome Sequencing. FRONTIERS IN PLANT SCIENCE 2021; 12:671598. [PMID: 34140964 PMCID: PMC8204250 DOI: 10.3389/fpls.2021.671598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Tobacco (Nicotiana tabacum L.) is a complex allotetraploid species with a large 4.5-Gb genome that carries duplicated gene copies. In this study, we describe the development of a whole-exome sequencing (WES) procedure in tobacco and its application to characterize a test population of ethyl methanesulfonate (EMS)-induced mutations. A probe set covering 50.3-Mb protein coding regions was designed from a reference tobacco genome. The EMS-induced mutations in 19 individual M2 lines were analyzed using our mutation analysis pipeline optimized to minimize false positives/negatives. In the target regions, the on-target rate of WES was approximately 75%, and 61,146 mutations were detected in the 19 M2 lines. Most of the mutations (98.8%) were single nucleotide variants, and 95.6% of them were C/G to T/A transitions. The number of mutations detected in the target coding sequences by WES was 93.5% of the mutations detected by whole-genome sequencing (WGS). The amount of sequencing data necessary for efficient mutation detection was significantly lower in WES (11.2 Gb), which is only 6.2% of the required amount in WGS (180 Gb). Thus, WES was almost comparable to WGS in performance but is more cost effective. Therefore, the developed target exome sequencing, which could become a fundamental tool in high-throughput mutation identification, renders the genome-wide analysis of tobacco highly efficient.
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Affiliation(s)
- Hisashi Udagawa
- Leaf Tobacco Research Center, Japan Tobacco Inc., Oyama, Japan
| | - Hiroyuki Ichida
- RIKEN Nishina Center for Accelerator-Based Science, Wako, Japan
| | | | - Tomoko Abe
- RIKEN Nishina Center for Accelerator-Based Science, Wako, Japan
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