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Genomics of Clinal Local Adaptation in Pinus sylvestris Under Continuous Environmental and Spatial Genetic Setting. G3-GENES GENOMES GENETICS 2020; 10:2683-2696. [PMID: 32546502 PMCID: PMC7407466 DOI: 10.1534/g3.120.401285] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Understanding the consequences of local adaptation at the genomic diversity is a central goal in evolutionary genetics of natural populations. In species with large continuous geographical distributions the phenotypic signal of local adaptation is frequently clear, but the genetic basis often remains elusive. We examined the patterns of genetic diversity in Pinus sylvestris, a keystone species in many Eurasian ecosystems with a huge distribution range and decades of forestry research showing that it is locally adapted to the vast range of environmental conditions. Making P. sylvestris an even more attractive subject of local adaptation study, population structure has been shown to be weak previously and in this study. However, little is known about the molecular genetic basis of adaptation, as the massive size of gymnosperm genomes has prevented large scale genomic surveys. We generated a both geographically and genomically extensive dataset using a targeted sequencing approach. By applying divergence-based and landscape genomics methods we identified several loci contributing to local adaptation, but only few with large allele frequency changes across latitude. We also discovered a very large (ca. 300 Mbp) putative inversion potentially under selection, which to our knowledge is the first such discovery in conifers. Our results call for more detailed analysis of structural variation in relation to genomic basis of local adaptation, emphasize the lack of large effect loci contributing to local adaptation in the coding regions and thus point out the need for more attention toward multi-locus analysis of polygenic adaptation.
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52
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Šmíd J, Douda J, Krak K, Mandák B. Analyses of Hybrid Viability across a Hybrid Zone between Two Alnus Species Using Microsatellites and cpDNA Markers. Genes (Basel) 2020; 11:E770. [PMID: 32659930 PMCID: PMC7397206 DOI: 10.3390/genes11070770] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 01/09/2023] Open
Abstract
Diploid Alnus glutinosa s. str. and autotetraploid A. rohlenae form a narrow hybrid zone in a study area in southern Serbia, which results in triploid hybrid formation. The vast majority of previous studies have been focused on studies of maternal plants, but the offspring resulting from their crossing have not been much studied. Here, we use the variability of microsatellites and chloroplast DNA between these species and their putative hybrids to create an overall picture of the development of the hybrid zone and its predicted type. To elucidate the gene transfer within both species, the origins of individual ploidies and especially the role of triploid hybrids, a germination experiment was carried out linked with a flow cytometry study of the resulting seedlings. The tension zone model seems to offer the most adequate explanation of our observations, with selection against triploid hybrids and the spatial positioning of the hybrid zone. Despite selection against them, the triploid hybrids play an important role in the exchange of genes between the two species and therefore serve as a bridge for introgression. The presence of fertile triploids is essential for enriching the haplotype diversity between these species and for the development of new genetic lineages.
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Affiliation(s)
- Jan Šmíd
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic; (J.Š.); (J.D.); (K.K.)
| | - Jan Douda
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic; (J.Š.); (J.D.); (K.K.)
| | - Karol Krak
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic; (J.Š.); (J.D.); (K.K.)
- Institute of Botany, Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Bohumil Mandák
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic; (J.Š.); (J.D.); (K.K.)
- Institute of Botany, Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
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53
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Völz R, Park JY, Kim S, Park SY, Harris W, Chung H, Lee YH. The rice/maize pathogen Cochliobolus spp. infect and reproduce on Arabidopsis revealing differences in defensive phytohormone function between monocots and dicots. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:412-429. [PMID: 32168401 DOI: 10.1111/tpj.14743] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 02/11/2020] [Accepted: 03/09/2020] [Indexed: 06/10/2023]
Abstract
The fungal genus Cochliobolus describes necrotrophic pathogens that give rise to significant losses on rice, wheat, and maize. Revealing plant mechanisms of non-host resistance (NHR) against Cochliobolus will help to uncover strategies that can be exploited in engineered cereals. Therefore, we developed a heterogeneous pathosystem and studied the ability of Cochliobolus to infect dicotyledons. We report here that C. miyabeanus and C. heterostrophus infect Arabidopsis accessions and produce functional conidia, thereby demonstrating the ability to accept Brassica spp. as host plants. Some ecotypes exhibited a high susceptibility, whereas others hindered the necrotrophic disease progression of the Cochliobolus strains. Natural variation in NHR among the tested Arabidopsis accessions can advance the identification of genetic loci that prime the plant's defence repertoire. We found that applied phytotoxin-containing conidial fluid extracts of C. miyabeanus caused necrotic lesions on rice leaves but provoked only minor irritations on Arabidopsis. This result implies that C. miyabeanus phytotoxins are insufficiently adapted to promote dicot colonization, which corresponds to a retarded infection progression. Previous studies on rice demonstrated that ethylene (ET) promotes C. miyabeanus infection, whereas salicylic acid (SA) and jasmonic acid (JA) exert a minor function. However, in Arabidopsis, we revealed that the genetic disruption of the ET and JA signalling pathways compromises basal resistance against Cochliobolus, whereas SA biosynthesis mutants showed a reduced susceptibility. Our results refer to the synergistic action of ET/JA and indicate distinct defence systems between Arabidopsis and rice to confine Cochliobolus propagation. Moreover, this heterogeneous pathosystem may help to reveal mechanisms of NHR and associated defensive genes against Cochliobolus infection.
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Affiliation(s)
- Ronny Völz
- Plant Immunity Research Center, Seoul National University, Seoul, 08826, Korea
| | - Ju-Young Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Korea
- R&D Institute, YUHAN Inc., Yongin, 17084, Korea
| | - Soonok Kim
- Genetic Resources Assessment Division, National Institute of Biological Resources, Incheon, 22689, Korea
| | - Sook-Young Park
- Department of Plant Medicine, Suncheon National University, Suncheon, 57922, Korea
| | - William Harris
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Korea
| | - Hyunjung Chung
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Korea
| | - Yong-Hwan Lee
- Plant Immunity Research Center, Seoul National University, Seoul, 08826, Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Korea
- Center for Fungal Genetic Resources, Seoul National University, Seoul, 08826, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Korea
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54
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Castilla AR, Méndez-Vigo B, Marcer A, Martínez-Minaya J, Conesa D, Picó FX, Alonso-Blanco C. Ecological, genetic and evolutionary drivers of regional genetic differentiation in Arabidopsis thaliana. BMC Evol Biol 2020; 20:71. [PMID: 32571210 PMCID: PMC7310121 DOI: 10.1186/s12862-020-01635-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/01/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Disentangling the drivers of genetic differentiation is one of the cornerstones in evolution. This is because genetic diversity, and the way in which it is partitioned within and among populations across space, is an important asset for the ability of populations to adapt and persist in changing environments. We tested three major hypotheses accounting for genetic differentiation-isolation-by-distance (IBD), isolation-by-environment (IBE) and isolation-by-resistance (IBR)-in the annual plant Arabidopsis thaliana across the Iberian Peninsula, the region with the largest genomic diversity. To that end, we sampled, genotyped with genome-wide SNPs, and analyzed 1772 individuals from 278 populations distributed across the Iberian Peninsula. RESULTS IBD, and to a lesser extent IBE, were the most important drivers of genetic differentiation in A. thaliana. In other words, dispersal limitation, genetic drift, and to a lesser extent local adaptation to environmental gradients, accounted for the within- and among-population distribution of genetic diversity. Analyses applied to the four Iberian genetic clusters, which represent the joint outcome of the long demographic and adaptive history of the species in the region, showed similar results except for one cluster, in which IBR (a function of landscape heterogeneity) was the most important driver of genetic differentiation. Using spatial hierarchical Bayesian models, we found that precipitation seasonality and topsoil pH chiefly accounted for the geographic distribution of genetic diversity in Iberian A. thaliana. CONCLUSIONS Overall, the interplay between the influence of precipitation seasonality on genetic diversity and the effect of restricted dispersal and genetic drift on genetic differentiation emerges as the major forces underlying the evolutionary trajectory of Iberian A. thaliana.
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Affiliation(s)
- Antonio R Castilla
- Centre for Applied Ecology "Prof. Baeta Neves", InBIO, School of Agriculture, University of Lisbon, Lisbon, Portugal
- Departamento de Ecología Integrativa, Estación Biológica de Doñana (EBD), Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
| | - Belén Méndez-Vigo
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Arnald Marcer
- CREAF, Centre de Recerca Ecològica i Aplicacions Forestals, Bellaterra, E08193, Cerdanyola de Vallès, Catalonia, Spain
- Universitat Autònoma de Barcelona, Bellaterra, E08193, Cerdanyola de Vallès, Catalonia, Spain
| | | | - David Conesa
- Departament d'Estadística i Investigació Operativa, Universitat de València, Valencia, Spain
| | - F Xavier Picó
- Departamento de Ecología Integrativa, Estación Biológica de Doñana (EBD), Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain.
| | - Carlos Alonso-Blanco
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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55
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Tsuchimatsu T, Kakui H, Yamazaki M, Marona C, Tsutsui H, Hedhly A, Meng D, Sato Y, Städler T, Grossniklaus U, Kanaoka MM, Lenhard M, Nordborg M, Shimizu KK. Adaptive reduction of male gamete number in the selfing plant Arabidopsis thaliana. Nat Commun 2020; 11:2885. [PMID: 32514036 PMCID: PMC7280297 DOI: 10.1038/s41467-020-16679-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 05/19/2020] [Indexed: 11/08/2022] Open
Abstract
The number of male gametes is critical for reproductive success and varies between and within species. The evolutionary reduction of the number of pollen grains encompassing the male gametes is widespread in selfing plants. Here, we employ genome-wide association study (GWAS) to identify underlying loci and to assess the molecular signatures of selection on pollen number-associated loci in the predominantly selfing plant Arabidopsis thaliana. Regions of strong association with pollen number are enriched for signatures of selection, indicating polygenic selection. We isolate the gene REDUCED POLLEN NUMBER1 (RDP1) at the locus with the strongest association. We validate its effect using a quantitative complementation test with CRISPR/Cas9-generated null mutants in nonstandard wild accessions. In contrast to pleiotropic null mutants, only pollen numbers are significantly affected by natural allelic variants. These data support theoretical predictions that reduced investment in male gametes is advantageous in predominantly selfing species.
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Affiliation(s)
- Takashi Tsuchimatsu
- Department of Evolutionary Biology and Environmental Studies & Zurich-Basel Plant Science Center, University of Zurich, 8057, Zurich, Switzerland
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008, Zurich, Switzerland
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, A-1030, Vienna, Austria
- Department of Biology, Chiba University, Chiba, 263-8522, Japan
- Department of Biological Sciences, University of Tokyo, Tokyo, 113-0033, Japan
| | - Hiroyuki Kakui
- Department of Evolutionary Biology and Environmental Studies & Zurich-Basel Plant Science Center, University of Zurich, 8057, Zurich, Switzerland
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, 244-0813, Japan
- Graduate School of Science and Technology, Niigata University, Niigata, 950-2181, Japan
| | - Misako Yamazaki
- Department of Evolutionary Biology and Environmental Studies & Zurich-Basel Plant Science Center, University of Zurich, 8057, Zurich, Switzerland
| | - Cindy Marona
- Institute for Biochemistry and Biology, University of Potsdam, 14476, Potsdam, Germany
| | - Hiroki Tsutsui
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008, Zurich, Switzerland
- Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
- JST ERATO Higashiyama Live-Holonics Project, Nagoya University, Nagoya, 464-8602, Japan
| | - Afif Hedhly
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008, Zurich, Switzerland
| | - Dazhe Meng
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, A-1030, Vienna, Austria
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA, 90089-0371, USA
| | - Yutaka Sato
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Thomas Städler
- Institute of Integrative Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008, Zurich, Switzerland
| | | | - Michael Lenhard
- Institute for Biochemistry and Biology, University of Potsdam, 14476, Potsdam, Germany
| | - Magnus Nordborg
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, A-1030, Vienna, Austria
| | - Kentaro K Shimizu
- Department of Evolutionary Biology and Environmental Studies & Zurich-Basel Plant Science Center, University of Zurich, 8057, Zurich, Switzerland.
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008, Zurich, Switzerland.
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, 244-0813, Japan.
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56
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Humble E, Dobrynin P, Senn H, Chuven J, Scott AF, Mohr DW, Dudchenko O, Omer AD, Colaric Z, Lieberman Aiden E, Al Dhaheri SS, Wildt D, Oliaji S, Tamazian G, Pukazhenthi B, Ogden R, Koepfli KP. Chromosomal-level genome assembly of the scimitar-horned oryx: Insights into diversity and demography of a species extinct in the wild. Mol Ecol Resour 2020; 20:1668-1681. [PMID: 32365406 DOI: 10.1111/1755-0998.13181] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/09/2020] [Accepted: 04/24/2020] [Indexed: 01/04/2023]
Abstract
Captive populations provide a valuable insurance against extinctions in the wild. However, they are also vulnerable to the negative impacts of inbreeding, selection and drift. Genetic information is therefore considered a critical aspect of conservation management. Recent developments in sequencing technologies have the potential to improve the outcomes of management programmes; however, the transfer of these approaches to applied conservation has been slow. The scimitar-horned oryx (Oryx dammah) is a North African antelope that has been extinct in the wild since the early 1980s and is the focus of a large-scale and long-term reintroduction project. To enable the selection of suitable founder individuals, facilitate post-release monitoring and improve captive breeding management, comprehensive genomic resources are required. Here, we used 10X Chromium sequencing together with Hi-C contact mapping to develop a chromosomal-level genome assembly for the species. The resulting assembly contained 29 chromosomes with a scaffold N50 of 100.4 Mb, and displayed strong chromosomal synteny with the cattle genome. Using resequencing data from six additional individuals, we demonstrated relatively high genetic diversity in the scimitar-horned oryx compared to other mammals, despite it having experienced a strong founding event in captivity. Additionally, the level of diversity across populations varied according to management strategy. Finally, we uncovered a dynamic demographic history that coincided with periods of climate variation during the Pleistocene. Overall, our study provides a clear example of how genomic data can uncover valuable insights into captive populations and contributes important resources to guide future management decisions of an endangered species.
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Affiliation(s)
- Emily Humble
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Pavel Dobrynin
- Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Front Royal, VA, USA.,Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Washington, DC, USA.,Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, St. Petersburg, Russia
| | - Helen Senn
- RZSS WildGenes Laboratory, Conservation Department, Royal Zoological Society of Scotland, Edinburgh, UK
| | - Justin Chuven
- Terrestrial & Marine Biodiversity Sector, Environment Agency, Abu Dhabi, United Arab Emirates
| | - Alan F Scott
- Genetic Resources Core Facility, McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David W Mohr
- Genetic Resources Core Facility, McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Olga Dudchenko
- The Center for Genome Architecture, Department of Molecular and Human Genetics Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Department of Computational and Applied Mathematics, Rice University, Houston, TX, USA.,Center for Theoretical and Biological Physics, Rice University, Houston, TX, USA
| | - Arina D Omer
- The Center for Genome Architecture, Department of Molecular and Human Genetics Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Department of Computational and Applied Mathematics, Rice University, Houston, TX, USA
| | - Zane Colaric
- The Center for Genome Architecture, Department of Molecular and Human Genetics Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Department of Computational and Applied Mathematics, Rice University, Houston, TX, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Department of Molecular and Human Genetics Baylor College of Medicine, Houston, TX, USA.,Department of Computer Science, Department of Computational and Applied Mathematics, Rice University, Houston, TX, USA.,Center for Theoretical and Biological Physics, Rice University, Houston, TX, USA.,Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | | | - David Wildt
- Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Front Royal, VA, USA.,Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Washington, DC, USA
| | - Shireen Oliaji
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Gaik Tamazian
- Computer Technologies Laboratory, ITMO University, St. Petersburg, Russia
| | - Budhan Pukazhenthi
- Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Front Royal, VA, USA.,Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Washington, DC, USA
| | - Rob Ogden
- Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Klaus-Peter Koepfli
- Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Front Royal, VA, USA.,Smithsonian Conservation Biology Institute, Center for Species Survival, National Zoological Park, Washington, DC, USA
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57
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Slaten ML, Yobi A, Bagaza C, Chan YO, Shrestha V, Holden S, Katz E, Kanstrup C, Lipka AE, Kliebenstein DJ, Nour-Eldin HH, Angelovici R. mGWAS Uncovers Gln-Glucosinolate Seed-Specific Interaction and its Role in Metabolic Homeostasis. PLANT PHYSIOLOGY 2020; 183:483-500. [PMID: 32317360 PMCID: PMC7271782 DOI: 10.1104/pp.20.00039] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/26/2020] [Indexed: 05/04/2023]
Abstract
Gln is a key player in plant metabolism. It is one of the major free amino acids that is transported into the developing seed and is central for nitrogen metabolism. However, Gln natural variation and its regulation and interaction with other metabolic processes in seeds remain poorly understood. To investigate the latter, we performed a metabolic genome-wide association study (mGWAS) of Gln-related traits measured from the dry seeds of the Arabidopsis (Arabidopsis thaliana) diversity panel using all potential ratios between Gln and the other members of the Glu family as traits. This semicombinatorial approach yielded multiple candidate genes that, upon further analysis, revealed an unexpected association between the aliphatic glucosinolates (GLS) and the Gln-related traits. This finding was confirmed by an independent quantitative trait loci mapping and statistical analysis of the relationships between the Gln-related traits and the presence of specific GLS in seeds. Moreover, an analysis of Arabidopsis mutants lacking GLS showed an extensive seed-specific impact on Gln levels and composition that manifested early in seed development. The elimination of GLS in seeds was associated with a large effect on seed nitrogen and sulfur homeostasis, which conceivably led to the Gln response. This finding indicates that both Gln and GLS play key roles in shaping the seed metabolic homeostasis. It also implies that select secondary metabolites might have key functions in primary seed metabolism. Finally, our study shows that an mGWAS performed on dry seeds can uncover key metabolic interactions that occur early in seed development.
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Affiliation(s)
- Marianne L Slaten
- Division of Biological Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Abou Yobi
- Division of Biological Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Clement Bagaza
- Division of Biological Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Yen On Chan
- Division of Biological Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Vivek Shrestha
- Division of Biological Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Samuel Holden
- Division of Biological Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Ella Katz
- Department of Plant Sciences, University of California Davis, Davis, California 95616
| | - Christa Kanstrup
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Alexander E Lipka
- Department of Crop Sciences, University of Illinois, Urbana, Illinois 61801
| | - Daniel J Kliebenstein
- Department of Plant Sciences, University of California Davis, Davis, California 95616
| | - Hussam Hassan Nour-Eldin
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Ruthie Angelovici
- Division of Biological Sciences, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
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58
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Brosseau C, Bolaji A, Roussin-Léveillée C, Zhao Z, Biga S, Moffett P. Natural variation in the Arabidopsis AGO2 gene is associated with susceptibility to potato virus X. THE NEW PHYTOLOGIST 2020; 226:866-878. [PMID: 31880814 DOI: 10.1111/nph.16397] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/12/2019] [Indexed: 06/10/2023]
Abstract
RNA silencing functions as an anti-viral defence in plants through the action of DICER-like (DCL) and ARGONAUTE (AGO) proteins. Despite the importance of this mechanism, little is known about the functional consequences of variation in genes encoding RNA silencing components. The AGO2 protein has been shown to be important for defense against multiple viruses, and we investigated how naturally occurring differences in AGO2 between and within species affects its antiviral activities. We find that the AGO2 protein from Arabidopsis thaliana, but not Nicotiana benthamiana, effectively limits potato virus X (PVX). Consistent with this, we find that the A. thaliana AGO2 gene shows a high incidence of polymorphisms between accessions, with evidence of selective pressure. Using functional analyses, we identify polymorphisms that specifically affect AGO2 antiviral activity, without interfering with other AGO2-associated functions such as anti-bacterial resistance or DNA methylation. Our results suggest that viruses adapt to overcome RNA silencing in their hosts. Furthermore, they indicate that plant-virus interactions have influenced natural variation in RNA-silencing components and that the latter may be a source of genetically encoded virus resistance.
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Affiliation(s)
- Chantal Brosseau
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Ayooluwa Bolaji
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | | | - Zhenxing Zhao
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Sébastien Biga
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Peter Moffett
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
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59
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Arouisse B, Korte A, van Eeuwijk F, Kruijer W. Imputation of 3 million SNPs in the Arabidopsis regional mapping population. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:872-882. [PMID: 31856318 PMCID: PMC7318218 DOI: 10.1111/tpj.14659] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/02/2019] [Accepted: 12/05/2019] [Indexed: 06/01/2023]
Abstract
Natural variation has become a prime resource to identify genetic variants that contribute to phenotypic variation. The regional mapping (RegMap) population is one of the most important populations for studying natural variation in Arabidopsis thaliana, and has been used in a large number of association studies and in studies on climatic adaptation. However, only 413 RegMap accessions have been completely sequenced, as part of the 1001 Genomes (1001G) Project, while the remaining 894 accessions have only been genotyped with the Affymetrix 250k chip. As a consequence, most association studies involving the RegMap are either restricted to the sequenced accessions, reducing power, or rely on a limited set of SNPs. Here we impute millions of SNPs to the 894 accessions that are exclusive to the RegMap, using the 1135 accessions of the 1001G Project as the reference panel. We assess imputation accuracy using a novel cross-validation scheme, which we show provides a more reliable measure of accuracy than existing methods. After filtering out low accuracy SNPs, we obtain high-quality genotypic information for 2029 accessions and 3 million markers. To illustrate the benefits of these imputed data, we reconducted genome-wide association studies on five stress-related traits and could identify novel candidate genes.
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Affiliation(s)
- Bader Arouisse
- BiometrisWageningen University & ResearchWageningenNetherlands
| | - Arthur Korte
- Centre for Computational and Theoretical BiologyUniversity of WürzburgWürzburgGermany
| | | | - Willem Kruijer
- BiometrisWageningen University & ResearchWageningenNetherlands
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60
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Böckelmann J, Tremetsberger K, Šumberová K, Kohl G, Grausgruber H, Bernhardt K. Genetic variation in an ephemeral mudflat species: The role of the soil seed bank and dispersal in river and secondary anthropogenic habitats. Ecol Evol 2020; 10:3620-3635. [PMID: 32313622 PMCID: PMC7160169 DOI: 10.1002/ece3.6109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 11/05/2019] [Accepted: 01/20/2020] [Indexed: 01/27/2023] Open
Abstract
Many ephemeral mudflat species, which rely on a soil seed bank to build up the next generation, are endangered in their natural habitat due to the widespread regulation of rivers. The aim of the present study was to elucidate the role of the soil seed bank and dispersal for the maintenance of genetic diversity in populations of near-natural river habitats and anthropogenic habitats created by traditional fish farming practices using Cyperus fuscus as a model. Using microsatellite markers, we found no difference in genetic diversity levels between soil seed bank and above-ground population and only moderate differentiation between the two fractions. One possible interpretation is the difference in short-term selection during germination under specific conditions (glasshouse versus field) resulting in an ecological filtering of genotypes out of the reservoir in the soil. River populations harbored significantly more genetic diversity than populations from the anthropogenic pond types. We suggest that altered levels and patterns of dispersal together with stronger selection pressures and historical bottlenecks in anthropogenic habitats are responsible for the observed reduction in genetic diversity. Dispersal is also supposed to largely prohibit genetic structure across Europe, although there is a gradient in private allelic richness from southern Europe (high values) to northern, especially north-western, Europe (low values), which probably relates to postglacial expansion out of southern and/or eastern refugia.
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Affiliation(s)
- Jörg Böckelmann
- Department of Integrative Biology and Biodiversity ResearchInstitute of BotanyUniversity of Natural Resources and Life SciencesViennaAustria
- Present address:
Division of Tropical Ecology and Animal BiodiversityDepartment of Botany and Biodiversity ResearchUniversity of ViennaViennaAustria
| | - Karin Tremetsberger
- Department of Integrative Biology and Biodiversity ResearchInstitute of BotanyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Kateřina Šumberová
- Department of Vegetation EcologyInstitute of BotanyThe Czech Academy of SciencesBrnoCzech Republic
| | - Gudrun Kohl
- Department of Integrative Biology and Biodiversity ResearchInstitute of BotanyUniversity of Natural Resources and Life SciencesViennaAustria
- Present address:
Division of Microbial EcologyDepartment of Microbiology and Ecosystem ScienceUniversity of ViennaViennaAustria
| | - Heinrich Grausgruber
- Division of Plant BreedingDepartment of Crop SciencesUniversity of Natural Resources and Life SciencesViennaAustria
| | - Karl‐Georg Bernhardt
- Department of Integrative Biology and Biodiversity ResearchInstitute of BotanyUniversity of Natural Resources and Life SciencesViennaAustria
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61
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Wang J, Street NR, Park EJ, Liu J, Ingvarsson PK. Evidence for widespread selection in shaping the genomic landscape during speciation of Populus. Mol Ecol 2020; 29:1120-1136. [PMID: 32068935 DOI: 10.1111/mec.15388] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 12/13/2022]
Abstract
Increasing our understanding of how evolutionary processes drive the genomic landscape of variation is fundamental to a better understanding of the genomic consequences of speciation. However, genome-wide patterns of within- and between- species variation have not been fully investigated in most forest tree species despite their global ecological and economic importance. Here, we use whole-genome resequencing data from four Populus species spanning the speciation continuum to reconstruct their demographic histories and investigate patterns of diversity and divergence within and between species. Using Populus trichocarpa as an outgroup species, we further infer the genealogical relationships and estimate the extent of ancient introgression among the three aspen species (Populus tremula, Populus davidiana and Populus tremuloides) throughout the genome. Our results show substantial variation in these patterns along the genomes with this variation being strongly predicted by local recombination rates and the density of functional elements. This implies that the interaction between recurrent selection and intrinsic genomic features has dramatically sculpted the genomic landscape over long periods of time. In addition, our findings provide evidence that, apart from background selection, recent positive selection and long-term balancing selection have also been crucial components in shaping patterns of genome-wide variation during the speciation process.
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Affiliation(s)
- Jing Wang
- Key Laboratory for Bio-Resources and Eco-Environment, College of Life Science, Sichuan University, Chengdu, China
| | - Nathaniel R Street
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Eung-Jun Park
- Department of Bioresources, National Institute of Forest Science, Suwon, Korea
| | - Jianquan Liu
- Key Laboratory for Bio-Resources and Eco-Environment, College of Life Science, Sichuan University, Chengdu, China
| | - Pär K Ingvarsson
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
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62
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Kim TS, Wang L, Kim YJ, Somers DE. Compensatory Mutations in GI and ZTL May Modulate Temperature Compensation in the Circadian Clock. PLANT PHYSIOLOGY 2020; 182:1130-1141. [PMID: 31740505 PMCID: PMC6997678 DOI: 10.1104/pp.19.01120] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/02/2019] [Indexed: 05/04/2023]
Abstract
Circadian systems share the three properties of entrainment, free-running period, and temperature compensation (TC). TC ensures nearly the same period over a broad range of physiologically relevant temperatures; however, the mechanisms behind TC remain poorly understood. Here, we identify single point mutations in two key elements of the Arabidopsis circadian clock, GIGANTEA (GI) and ZEITLUPE (ZTL), which likely act as compensatory substitutions to establish a remarkably constant free-running period over a wide range of temperatures. Using near-isogenic lines generated from the introgression of the Cape Verde Islands (Cvi) alleles of GI and ZTL into the Landsberg erecta (Ler) background, we show how longer periods in the Cvi background at higher temperatures correlate with a difference in strength of the GI/ZTL interaction. Pairwise interaction testing of all GI/ZTL allelic combinations shows similar affinities for isogenic alleles at 22°C, but very poor interaction between GI (Cvi) and ZTL (Cvi) at higher temperature. In vivo, this would result in lower ZTL levels at high temperatures leading to longer periods in the Cvi background. Mismatched allelic combinations result in extremely strong or weak GI/ZTL interactions, indicating how the corresponding natural variants likely became fixed through epistatic selection. Additionally, molecular characterization of GI (Cvi) reveals a novel functional motif that can modulate the GI/ZTL interaction as well as nucleocytoplasmic partitioning. Taken together, these results identify a plausible temperature-dependent molecular mechanism, which contributes to the robustness of TC through natural variation in GI and ZTL alleles found on the Cape Verde Islands.
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Affiliation(s)
- Tae-Sung Kim
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210
| | - Lei Wang
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210
| | - Yeon Jeong Kim
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210
| | - David E Somers
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210
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63
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Mattila TM, Laenen B, Slotte T. Population Genomics of Transitions to Selfing in Brassicaceae Model Systems. Methods Mol Biol 2020; 2090:269-287. [PMID: 31975171 DOI: 10.1007/978-1-0716-0199-0_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Many plants harbor complex mechanisms that promote outcrossing and efficient pollen transfer. These include floral adaptations as well as genetic mechanisms, such as molecular self-incompatibility (SI) systems. The maintenance of such systems over long evolutionary timescales suggests that outcrossing is favorable over a broad range of conditions. Conversely, SI has repeatedly been lost, often in association with transitions to self-fertilization (selfing). This transition is favored when the short-term advantages of selfing outweigh the costs, primarily inbreeding depression. The transition to selfing is expected to have major effects on population genetic variation and adaptive potential, as well as on genome evolution. In the Brassicaceae, many studies on the population genetic, gene regulatory, and genomic effects of selfing have centered on the model plant Arabidopsis thaliana and the crucifer genus Capsella. The accumulation of population genomics datasets have allowed detailed investigation of where, when and how the transition to selfing occurred. Future studies will take advantage of the development of population genetics theory on the impact of selfing, especially regarding positive selection. Furthermore, investigation of systems including recent transitions to selfing, mixed mating populations and/or multiple independent replicates of the same transition will facilitate dissecting the effects of mating system variation from processes driven by demography.
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Affiliation(s)
- Tiina M Mattila
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
| | - Benjamin Laenen
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Tanja Slotte
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden.
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64
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Pyhäjärvi T, Kujala ST, Savolainen O. 275 years of forestry meets genomics in Pinus sylvestris. Evol Appl 2020; 13:11-30. [PMID: 31988655 PMCID: PMC6966708 DOI: 10.1111/eva.12809] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 04/05/2019] [Accepted: 04/24/2019] [Indexed: 12/12/2022] Open
Abstract
Pinus sylvestris has a long history of basic and applied research that is relevant for both forestry and evolutionary studies. Its patterns of adaptive variation and role in forest economic and ecological systems have been studied extensively for nearly 275 years, detailed demography for a 100 years and mating system more than 50 years. However, its reference genome sequence is not yet available and genomic studies have been lagging compared to, for example, Pinus taeda and Picea abies, two other economically important conifers. Despite the lack of reference genome, many modern genomic methods are applicable for a more detailed look at its biological characteristics. For example, RNA-seq has revealed a complex transcriptional landscape and targeted DNA sequencing displays an excess of rare variants and geographically homogenously distributed molecular genetic diversity. Current DNA and RNA resources can be used as a reference for gene expression studies, SNP discovery, and further targeted sequencing. In the future, specific consequences of the large genome size, such as functional effects of regulatory open chromatin regions and transposable elements, should be investigated more carefully. For forest breeding and long-term management purposes, genomic data can help in assessing the genetic basis of inbreeding depression and the application of genomic tools for genomic prediction and relatedness estimates. Given the challenges of breeding (long generation time, no easy vegetative propagation) and the economic importance, application of genomic tools has a potential to have a considerable impact. Here, we explore how genomic characteristics of P. sylvestris, such as rare alleles and the low extent of linkage disequilibrium, impact the applicability and power of the tools.
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Affiliation(s)
- Tanja Pyhäjärvi
- Department of Ecology and GeneticsUniversity of OuluOuluFinland
- Biocenter OuluUniversity of OuluOuluFinland
| | | | - Outi Savolainen
- Department of Ecology and GeneticsUniversity of OuluOuluFinland
- Biocenter OuluUniversity of OuluOuluFinland
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65
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Greenbaum G, Rubin A, Templeton AR, Rosenberg NA. Network-based hierarchical population structure analysis for large genomic data sets. Genome Res 2019; 29:2020-2033. [PMID: 31694865 PMCID: PMC6886512 DOI: 10.1101/gr.250092.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 11/01/2019] [Indexed: 01/24/2023]
Abstract
Analysis of population structure in natural populations using genetic data is a common practice in ecological and evolutionary studies. With large genomic data sets of populations now appearing more frequently across the taxonomic spectrum, it is becoming increasingly possible to reveal many hierarchical levels of structure, including fine-scale genetic clusters. To analyze these data sets, methods need to be appropriately suited to the challenges of extracting multilevel structure from whole-genome data. Here, we present a network-based approach for constructing population structure representations from genetic data. The use of community-detection algorithms from network theory generates a natural hierarchical perspective on the representation that the method produces. The method is computationally efficient, and it requires relatively few assumptions regarding the biological processes that underlie the data. We show the approach by analyzing population structure in the model plant species Arabidopsis thaliana and in human populations. These examples illustrate how network-based approaches for population structure analysis are well-suited to extracting valuable ecological and evolutionary information in the era of large genomic data sets.
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Affiliation(s)
- Gili Greenbaum
- Department of Biology, Stanford University, Stanford, California 94305, USA
| | - Amir Rubin
- Department of Computer Science, Ben-Gurion University of the Negev, Be'er-Sheva, 8410501, Israel
| | - Alan R Templeton
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA
- Department of Evolutionary and Environmental Ecology, University of Haifa, Haifa, 31905, Israel
| | - Noah A Rosenberg
- Department of Biology, Stanford University, Stanford, California 94305, USA
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66
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Delgado D, Sánchez-Bermejo E, de Marcos A, Martín-Jimenez C, Fenoll C, Alonso-Blanco C, Mena M. A Genetic Dissection of Natural Variation for Stomatal Abundance Traits in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2019; 10:1392. [PMID: 31781138 PMCID: PMC6859887 DOI: 10.3389/fpls.2019.01392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 10/09/2019] [Indexed: 05/20/2023]
Abstract
Stomatal abundance varies widely across natural populations of Arabidopsis thaliana, and presumably affects plant performance because it influences water and CO2 exchange with the atmosphere and thence photosynthesis and transpiration. In order to determine the genetic basis of this natural variation, we have analyzed a recombinant inbred line (RIL) population derived from the wild accession Ll-0 and the reference strain Landsberg erecta (Ler), which show low and high stomatal abundance, respectively. Quantitative trait locus (QTL) analyses of stomatal index, stomatal density, and pavement cell density measured in the adaxial cotyledon epidermis, identified five loci. Three of the genomic regions affect all traits and were named MID (Modulator of Cell Index and Density) 1 to 3. MID2 is a large-effect QTL overlapping with ERECTA (ER), the er-1 allele from Ler increasing all trait values. Additional analyses of natural and induced loss-of-function er mutations in different genetic backgrounds revealed that ER dysfunctions have differential and opposite effects on the stomatal index in adaxial and abaxial cotyledon epidermis and confirmed that ER is the gene underlying MID2. Ll-0 alleles at MID1 and MID3 displayed moderate and positive effects on the various traits. Furthermore, detailed developmental studies tracking primary and satellite stomatal lineages show that MID3-Ll-0 allele promotes the spacing divisions that initiate satellite lineages, while the ER allele limits them. Finally, expression analyses suggest that ER and MID3 modulate satellization through partly different regulatory pathways. Our characterization of MID3 indicates that genetic modulation of satellization contributes to the variation for stomatal abundance in natural populations, and subsequently that this trait might be involved in plant adaptation.
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Affiliation(s)
- Dolores Delgado
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Eduardo Sánchez-Bermejo
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Alberto de Marcos
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Cristina Martín-Jimenez
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Carmen Fenoll
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
| | - Carlos Alonso-Blanco
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Montaña Mena
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain
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67
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Buffalo V, Coop G. The Linked Selection Signature of Rapid Adaptation in Temporal Genomic Data. Genetics 2019; 213:1007-1045. [PMID: 31558582 PMCID: PMC6827383 DOI: 10.1534/genetics.119.302581] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/22/2019] [Indexed: 11/18/2022] Open
Abstract
The majority of empirical population genetic studies have tried to understand the evolutionary processes that have shaped genetic variation in a single sample taken from a present-day population. However, genomic data collected over tens of generations in both natural and laboratory populations are increasingly used to find selected loci underpinning adaptation over these short timescales. Although these studies have been quite successful in detecting selection on large-effect loci, the fitness differences between individuals are often polygenic, such that selection leads to allele frequency changes that are difficult to distinguish from genetic drift. However, one promising signal comes from polygenic selection's effect on neutral sites that become stochastically associated with the genetic backgrounds that lead to fitness differences between individuals. Previous theoretical work has established that the random associations between a neutral allele and heritable fitness backgrounds act to reduce the effective population size experienced by this neutral allele. These associations perturb neutral allele frequency trajectories, creating autocovariance in the allele frequency changes across generations. Here, we show how temporal genomic data allow us to measure the temporal autocovariance in allele frequency changes and characterize the genome-wide impact of polygenic selection. We develop expressions for these temporal autocovariances, showing that their magnitude is determined by the level of additive genetic variation, recombination, and linkage disequilibria in a region. Furthermore, by using analytic expressions for the temporal variances and autocovariances in allele frequency, we demonstrate that one can estimate the additive genetic variation for fitness and the drift-effective population size from temporal genomic data. We also show how the proportion of total variation in allele frequency change due to linked selection can be estimated from temporal data. Overall, we demonstrate that temporal genomic data offer opportunities to identify the role of linked selection on genome-wide diversity over short timescales, and can help bridge population genetic and quantitative genetic studies of adaptation.
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Affiliation(s)
- Vince Buffalo
- Population Biology Graduate Group, University of California, Davis, California 95616
- Center for Population Biology, Department of Evolution and Ecology, University of California, Davis, California 95616
| | - Graham Coop
- Center for Population Biology, Department of Evolution and Ecology, University of California, Davis, California 95616
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68
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Ho EKH, Bartkowska M, Wright SI, Agrawal AF. Population genomics of the facultatively asexual duckweed Spirodela polyrhiza. THE NEW PHYTOLOGIST 2019; 224:1361-1371. [PMID: 31298732 DOI: 10.1111/nph.16056] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 06/18/2019] [Indexed: 06/10/2023]
Abstract
Clonal propagation allows some plant species to achieve massive population sizes quickly but also reduces the evolutionary independence of different sites in the genome. We examine genome-wide genetic diversity in Spirodela polyrhiza, a duckweed that reproduces primarily asexually. We find that this geographically widespread and numerically abundant species has very low levels of genetic diversity. Diversity at nonsynonymous sites relative to synonymous sites is high, suggesting that purifying selection is weak. A potential explanation for this observation is that a very low frequency of sex renders selection ineffective. However, there is a pronounced decay in linkage disequilibrium over 40 kb, suggesting that though sex may be rare at the individual level it is not too infrequent at the population level. In addition, neutral diversity is affected by the physical proximity of selected sites, which would be unexpected if sex was exceedingly rare at the population level. The amount of genetic mixing as assessed by the decay in linkage disequilibrium is not dissimilar from selfing species such as Arabidopsis thaliana, yet selection appears to be much less effective in duckweed. We discuss alternative explanations for the signature of weak purifying selection.
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Affiliation(s)
- Eddie K H Ho
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Magdalena Bartkowska
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Stephen I Wright
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
- Center for Analysis of Genome Evolution and Function, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Aneil F Agrawal
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
- Center for Analysis of Genome Evolution and Function, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
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69
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Population structure in landrace barley (Hordeum vulgare L.) during the late 19th century crop failures in Fennoscandia. Heredity (Edinb) 2019; 123:733-745. [PMID: 31616056 DOI: 10.1038/s41437-019-0277-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 11/08/2022] Open
Abstract
Agricultural disasters and the subsequent need for supply of relief seed can be expected to influence the genetic composition of crop plant populations. The consequences of disasters and seed relief have, however, rarely been studied since specimens sampled before the events are seldomly available. A series of crop failures struck northern Fennoscandia (Norway, Sweden and Finland) during the second half of the 19th century. In order to assess population genetic dynamics of landrace barley (Hordeum vulgare), and consequences of crop failure and possible seed relief during this time period, we genotyped seeds from 16 historical accessions originating from two time periods spanning the period of repeated crop failure. Reliable identification of genetic structuring is highly dependent on sampling regimes and detecting fine-scale geographic or temporal differentiation requires large sample sizes. The robustness of the results under different sampling regimes was evaluated by analyzing subsets of the data and an artificially pooled dataset. The results led to the conclusion that six individuals per accession were insufficient for reliable detection of the observed genetic structure. We found that population structure among the data was best explained by collection year of accessions, rather than geographic origin. The correlation with collection year indicated a change in genetic composition of landrace barley in the area after repeated crop failures, likely a consequence of introgression of relief seed in local populations. Identical genotypes were found to be shared among some accessions, suggesting founder effects and local seed exchange along known routes for trade and cultural exchange.
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70
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de Jong M, Tavares H, Pasam RK, Butler R, Ward S, George G, Melnyk CW, Challis R, Kover PX, Leyser O. Natural variation in Arabidopsis shoot branching plasticity in response to nitrate supply affects fitness. PLoS Genet 2019; 15:e1008366. [PMID: 31539368 PMCID: PMC6774567 DOI: 10.1371/journal.pgen.1008366] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 10/02/2019] [Accepted: 08/09/2019] [Indexed: 12/20/2022] Open
Abstract
The capacity of organisms to tune their development in response to environmental cues is pervasive in nature. This phenotypic plasticity is particularly striking in plants, enabled by their modular and continuous development. A good example is the activation of lateral shoot branches in Arabidopsis, which develop from axillary meristems at the base of leaves. The activity and elongation of lateral shoots depends on the integration of many signals both external (e.g. light, nutrient supply) and internal (e.g. the phytohormones auxin, strigolactone and cytokinin). Here, we characterise natural variation in plasticity of shoot branching in response to nitrate supply using two diverse panels of Arabidopsis lines. We find extensive variation in nitrate sensitivity across these lines, suggesting a genetic basis for variation in branching plasticity. High plasticity is associated with extreme branching phenotypes such that lines with the most branches on high nitrate have the fewest under nitrate deficient conditions. Conversely, low plasticity is associated with a constitutively moderate level of branching. Furthermore, variation in plasticity is associated with alternative life histories with the low plasticity lines flowering significantly earlier than high plasticity lines. In Arabidopsis, branching is highly correlated with fruit yield, and thus low plasticity lines produce more fruit than high plasticity lines under nitrate deficient conditions, whereas highly plastic lines produce more fruit under high nitrate conditions. Low and high plasticity, associated with early and late flowering respectively, can therefore be interpreted alternative escape vs mitigate strategies to low N environments. The genetic architecture of these traits appears to be highly complex, with only a small proportion of the estimated genetic variance detected in association mapping.
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Affiliation(s)
- Maaike de Jong
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Biology, University of York, York, United Kingdom
| | - Hugo Tavares
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Raj K. Pasam
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Rebecca Butler
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Sally Ward
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Biology, University of York, York, United Kingdom
| | - Gilu George
- Department of Biology, University of York, York, United Kingdom
| | - Charles W. Melnyk
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Richard Challis
- Department of Biology, University of York, York, United Kingdom
| | - Paula X. Kover
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Ottoline Leyser
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Biology, University of York, York, United Kingdom
- * E-mail:
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71
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MacQueen A, Tian D, Chang W, Holub E, Kreitman M, Bergelson J. Population Genetics of the Highly Polymorphic RPP8 Gene Family. Genes (Basel) 2019; 10:E691. [PMID: 31500388 PMCID: PMC6771003 DOI: 10.3390/genes10090691] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/31/2019] [Accepted: 09/03/2019] [Indexed: 02/06/2023] Open
Abstract
Plant nucleotide-binding domain and leucine-rich repeat containing (NLR) genes provide some of the most extreme examples of polymorphism in eukaryotic genomes, rivalling even the vertebrate major histocompatibility complex. Surprisingly, this is also true in Arabidopsis thaliana, a predominantly selfing species with low heterozygosity. Here, we investigate how gene duplication and intergenic exchange contribute to this extraordinary variation. RPP8 is a three-locus system that is configured chromosomally as either a direct-repeat tandem duplication or as a single copy locus, plus a locus 2 Mb distant. We sequenced 48 RPP8 alleles from 37 accessions of A. thaliana and 12 RPP8 alleles from Arabidopsis lyrata to investigate the patterns of interlocus shared variation. The tandem duplicates display fixed differences and share less variation with each other than either shares with the distant paralog. A high level of shared polymorphism among alleles at one of the tandem duplicates, the single-copy locus and the distal locus, must involve both classical crossing over and intergenic gene conversion. Despite these polymorphism-enhancing mechanisms, the observed nucleotide diversity could not be replicated under neutral forward-in-time simulations. Only by adding balancing selection to the simulations do they approach the level of polymorphism observed at RPP8. In this NLR gene triad, genetic architecture, gene function and selection all combine to generate diversity.
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Affiliation(s)
- Alice MacQueen
- Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Dacheng Tian
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210008, China.
| | - Wenhan Chang
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL 60637, USA.
| | - Eric Holub
- School of Life Sciences, Wellesbourne Innovation Campus, University of Warwick, Wellesbourne CV359EF, UK.
| | - Martin Kreitman
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL 60637, USA.
| | - Joy Bergelson
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL 60637, USA.
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Duszynska D, Vilhjalmsson B, Castillo Bravo R, Swamidatta S, Juenger TE, Donoghue MTA, Comte A, Nordborg M, Sharbel TF, Brychkova G, McKeown PC, Spillane C. Transgenerational effects of inter-ploidy cross direction on reproduction and F2 seed development of Arabidopsis thaliana F1 hybrid triploids. PLANT REPRODUCTION 2019; 32:275-289. [PMID: 30903284 PMCID: PMC6675909 DOI: 10.1007/s00497-019-00369-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 03/05/2019] [Indexed: 05/15/2023]
Abstract
KEY MESSAGE Reproduction in triploid plants is important for understanding polyploid population dynamics. We show that genetically identical reciprocal F1 hybrid triploids can display transgenerational epigenetic effects on viable F2 seed development. The success or failure of reproductive outcomes from intra-species crosses between plants of different ploidy levels is an important factor in flowering plant evolution and crop breeding. However, the effects of inter-ploidy cross directions on F1 hybrid offspring fitness are poorly understood. In Arabidopsis thaliana, hybridization between diploid and tetraploid plants can produce viable F1 triploid plants. When selfed, such F1 triploid plants act as aneuploid gamete production "machines" where the vast majority of gametes generated are aneuploid which, following sexual reproduction, can generate aneuploid swarms of F2 progeny (Henry et al. 2009). There is potential for some aneuploids to cause gametophyte abortion and/or F2 seed abortion (Henry et al. 2009). In this study, we analyse the reproductive success of 178 self-fertilized inter-accession F1 hybrid triploids and demonstrate that the proportions of aborted or normally developed F2 seeds from the selfed F1 triploids depend upon a combination of natural variation and cross direction, with strong interaction between these factors. Single-seed ploidy analysis indicates that the embryonic DNA content of phenotypically normal F2 seeds is highly variable and that these DNA content distributions are also affected by genotype and cross direction. Notably, genetically identical reciprocal F1 hybrid triploids display grandparent-of-origin effects on F2 seed set, and hence on the ability to tolerate aneuploidy in F2 seed. There are differences between reciprocal F1 hybrid triploids regarding the proportions of normal and aborted F2 seeds generated, and also for the DNA content averages and distributions of the F2 seeds. To identify genetic variation for tolerance of aneuploidy in F2 seeds, we carried out a GWAS which identified two SNPs, termed MOT and POT, which represent candidate loci for genetic control of the proportion of normal F2 seeds obtained from selfed F1 triploids. Parental and grandparental effects on F2 seeds obtained from selfed F1 triploids can have transgenerational consequences for asymmetric gene flow, emergence of novel genotypes in polyploid populations, and for control of F2 seed set in triploid crops.
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Affiliation(s)
- Dorota Duszynska
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
| | - Bjarni Vilhjalmsson
- Gregor Mendel Institute of Molecular Plant Biology, Vienna, Austria
- Present Address: Bioinformatics Research Centre, Aarhus University, Århus, Denmark
| | - Rosa Castillo Bravo
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
| | - Sandesh Swamidatta
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
- Present Address: Department of Biology, Centre for Novel Agricultural Products (CNAP), University of York, York, UK
| | - Thomas E. Juenger
- Section of Integrative Biology and Institute for Cellular and Molecular Biology, University of Texas, Austin, USA
| | - Mark T. A. Donoghue
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
- Present Address: Memorial Sloan Kettering Cancer Center, New York, NY USA
| | - Aurélie Comte
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
| | - Magnus Nordborg
- Gregor Mendel Institute of Molecular Plant Biology, Vienna, Austria
| | - Timothy F. Sharbel
- Apomixis Research Group, Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
- Seed and Developmental Biology Program, Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Galina Brychkova
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
| | - Peter C. McKeown
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
| | - Charles Spillane
- Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre (PABC), Ryan Institute, National University of Ireland, Galway, H91 REW4 Ireland
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73
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Farhat N, Hichri S, Hildebrandt TM, Debez A, Braun HP. Composition and Stability of the Oxidative Phosphorylation System in the Halophile Plant Cakile maritima. FRONTIERS IN PLANT SCIENCE 2019; 10:1010. [PMID: 31456813 PMCID: PMC6700300 DOI: 10.3389/fpls.2019.01010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 07/18/2019] [Indexed: 05/21/2023]
Abstract
Mitochondria play a central role in the energy metabolism of plants. At the same time, they provide energy for plant stress responses. We here report a first view on the mitochondrial Oxidative Phosphorylation (OXPHOS) system of the halophile (salt tolerant) plant Cakile maritima. Mitochondria were purified from suspension cultures of C. maritima and for comparison of Arabidopsis thaliana, a closely related glycophyte (salt sensitive) plant. Mitochondria were treated with digitonin and solubilized protein complexes were analyzed by 2D Blue native/SDS polyacrylamide gel electrophoresis. The OXPHOS systems of the two compared plants exhibit some distinct differences. C. maritima mitochondria include a very abundant respiratory supercomplex composed of monomeric complex I and dimeric complex III. At the same time the complexes II and IV are of reduced abundance. The stability of the OXPHOS complexes was investigated by combined salt and temperature treatments of isolated mitochondria. ATP synthase (complex V) is of increased stability in C. maritima. Also, the I + III2 supercomplex is present in high abundance during stress treatments. These results give insights into the mitochondrial contribution to the plant salt stress response.
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Affiliation(s)
- Nèjia Farhat
- Laboratory of Extremophile Plants, Center of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
- Department of Plant Proteomics, Institute of Plant Genetics, Leibniz University Hannover, Hanover, Germany
| | - Sarra Hichri
- Laboratory of Extremophile Plants, Center of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
- Department of Plant Proteomics, Institute of Plant Genetics, Leibniz University Hannover, Hanover, Germany
| | | | - Ahmed Debez
- Laboratory of Extremophile Plants, Center of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
- Department of Plant Proteomics, Institute of Plant Genetics, Leibniz University Hannover, Hanover, Germany
| | - Hans-Peter Braun
- Department of Plant Proteomics, Institute of Plant Genetics, Leibniz University Hannover, Hanover, Germany
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74
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Hamm MO, Moss BL, Leydon AR, Gala HP, Lanctot A, Ramos R, Klaeser H, Lemmex AC, Zahler ML, Nemhauser JL, Wright RC. Accelerating structure-function mapping using the ViVa webtool to mine natural variation. PLANT DIRECT 2019; 3:e00147. [PMID: 31372596 PMCID: PMC6658840 DOI: 10.1002/pld3.147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 04/20/2019] [Accepted: 04/29/2019] [Indexed: 05/13/2023]
Abstract
Thousands of sequenced genomes are now publicly available capturing a significant amount of natural variation within plant species; yet, much of these data remain inaccessible to researchers without significant bioinformatics experience. Here, we present a webtool called ViVa (Visualizing Variation) which aims to empower any researcher to take advantage of the amazing genetic resource collected in the Arabidopsis thaliana 1001 Genomes Project (http://1001genomes.org). ViVa facilitates data mining on the gene, gene family, or gene network level. To test the utility and accessibility of ViVa, we assembled a team with a range of expertise within biology and bioinformatics to analyze the natural variation within the well-studied nuclear auxin signaling pathway. Our analysis has provided further confirmation of existing knowledge and has also helped generate new hypotheses regarding this well-studied pathway. These results highlight how natural variation could be used to generate and test hypotheses about less-studied gene families and networks, especially when paired with biochemical and genetic characterization. ViVa is also readily extensible to databases of interspecific genetic variation in plants as well as other organisms, such as the 3,000 Rice Genomes Project ( http://snp-seek.irri.org/) and human genetic variation ( https://www.ncbi.nlm.nih.gov/clinvar/).
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Affiliation(s)
- Morgan O. Hamm
- Department of BiologyUniversity of WashingtonSeattleWashington
| | | | | | - Hardik P. Gala
- Department of BiologyUniversity of WashingtonSeattleWashington
| | - Amy Lanctot
- Department of BiologyUniversity of WashingtonSeattleWashington
| | - Román Ramos
- Department of BiologyUniversity of WashingtonSeattleWashington
| | - Hannah Klaeser
- Department of BiologyWhitman CollegeWalla WallaWashington
| | | | | | | | - R. Clay Wright
- Biological Systems EngineeringVirginia TechBlacksburgVirginia
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75
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Pucker B, Schilbert HM, Schumacher SF. Integrating Molecular Biology and Bioinformatics Education. J Integr Bioinform 2019; 16:/j/jib.ahead-of-print/jib-2019-0005/jib-2019-0005.xml. [PMID: 31145692 PMCID: PMC6798849 DOI: 10.1515/jib-2019-0005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 04/15/2019] [Indexed: 02/01/2023] Open
Abstract
Combined awareness about the power and limitations of bioinformatics and molecular biology enables advanced research based on high-throughput data. Despite an increasing demand of scientists with a combined background in both fields, the education of dry and wet lab subjects are often still separated. This work describes an example of integrated education with a focus on genomics and transcriptomics. Participants learned computational and molecular biology methods in the same practical course. Peer-review was applied as a teaching method to foster cooperative learning of students with heterogeneous backgrounds. The positive evaluation results indicate that this approach was accepted by the participants and would likely be suitable for wider scale application.
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Affiliation(s)
- Boas Pucker
- Genetics and Genomics of Plants, CeBiTec and Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Hanna Marie Schilbert
- Genetics and Genomics of Plants, CeBiTec and Faculty of Biology, Bielefeld University, Bielefeld, Germany
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76
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Bonhomme M, Fariello MI, Navier H, Hajri A, Badis Y, Miteul H, Samac DA, Dumas B, Baranger A, Jacquet C, Pilet-Nayel ML. A local score approach improves GWAS resolution and detects minor QTL: application to Medicago truncatula quantitative disease resistance to multiple Aphanomyces euteiches isolates. Heredity (Edinb) 2019; 123:517-531. [PMID: 31138867 DOI: 10.1038/s41437-019-0235-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/19/2019] [Accepted: 05/08/2019] [Indexed: 12/31/2022] Open
Abstract
Quantitative trait loci (QTL) with small effects, which are pervasive in quantitative phenotypic variation, are difficult to detect in genome-wide association studies (GWAS). To improve their detection, we propose to use a local score approach that accounts for the surrounding signal due to linkage disequilibrium, by accumulating association signals from contiguous single markers. Simulations revealed that, in a GWAS context with high marker density, the local score approach outperforms single SNP p-value-based tests for detecting minor QTL (heritability of 5-10%) and is competitive with regard to alternative methods, which also aggregate p-values. Using more than five million SNPs, this approach was applied to identify loci involved in Quantitative Disease Resistance (QDR) to different isolates of the plant root rot pathogen Aphanomyces euteiches, from a GWAS performed on a collection of 174 accessions of the model legume Medicago truncatula. We refined the position of a previously reported major locus, underlying MYB/NB-ARC/tyrosine kinase candidate genes conferring resistance to two closely related A. euteiches isolates belonging to pea pathotype I. We also discovered a diversity of minor resistance QTL, not detected using p-value-based tests, some of which being putatively shared in response to pea (pathotype I and III) and/or alfalfa (race 1 and 2) isolates. Candidate genes underlying these QTL suggest pathogen effector recognition and plant proteasome as key functions associated with M. truncatula resistance to A. euteiches. GWAS on any organism can benefit from the local score approach to uncover many weak-effect QTL.
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Affiliation(s)
- Maxime Bonhomme
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS), Castanet Tolosan, France.
| | - Maria Inés Fariello
- Universidad de la República, UdelaR, Facultad de Ingeniería, IMERL, Montevideo, Uruguay
| | - Hélène Navier
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, F-35650, Le Rheu, France
| | - Ahmed Hajri
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, F-35650, Le Rheu, France
| | - Yacine Badis
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS), Castanet Tolosan, France
| | - Henri Miteul
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, F-35650, Le Rheu, France
| | | | - Bernard Dumas
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS), Castanet Tolosan, France
| | - Alain Baranger
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, F-35650, Le Rheu, France
| | - Christophe Jacquet
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS), Castanet Tolosan, France
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77
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Lachagari VBR, Gupta R, Lekkala SP, Mahadevan L, Kuriakose B, Chakravartty N, Mohan Katta AVSK, Santhosh S, Reddy AR, Thomas G. Whole Genome Sequencing and Comparative Genomic Analysis Reveal Allelic Variations Unique to a Purple Colored Rice Landrace ( Oryza sativa ssp. indica cv. Purpleputtu). FRONTIERS IN PLANT SCIENCE 2019; 10:513. [PMID: 31134103 PMCID: PMC6516047 DOI: 10.3389/fpls.2019.00513] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 04/03/2019] [Indexed: 05/27/2023]
Abstract
Purpleputtu (Oryza sativa ssp. indica cv. Purpleputtu) is a unique rice landrace from southern India that exhibits predominantly purple color. This study reports the underlying genetic complexity of the trait, associated domestication and de-domestication processes during its coevolution with present day cultivars. Along-with genome level allelic variations in the entire gene repertoire associated with the purple, red coloration of grain and other plant parts. Comparative genomic analysis using 'a panel of 108 rice lines' revealed a total of 3,200,951 variants including 67,774 unique variations in Purpleputtu (PP) genome. Multiple sequence alignment uncovered a 14 bp deletion in Rc (Red colored, a transcription factor of bHLH class) locus of PP, a key regulatory gene of anthocyanin biosynthetic pathway. Interestingly, this deletion in Rc gene is a characteristic feature of the present-day white pericarped rice cultivars. Phylogenetic analysis of Rc locus revealed a distinct clade showing proximity to the progenitor species Oryza rufipogon and O. nivara. In addition, PP genome exhibits a well conserved 4.5 Mbp region on chromosome 5 that harbors several loci associated with domestication of rice. Further, PP showed 1,387 unique when SNPs compared to 3,023 lines of rice (SNP-Seek database). The results indicate that PP genome is rich in allelic diversity and can serve as an excellent resource for rice breeding for a variety of agronomically important traits such as disease resistance, enhanced nutritional values, stress tolerance, and protection from harmful UV-B rays.
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Affiliation(s)
- V. B. Reddy Lachagari
- AgriGenome Labs Pvt. Ltd., Biotechnology Incubation Center, MN iHub, Genome Valley, Hyderabad, India
| | - Ravi Gupta
- Medgenome Labs Ltd., Bengaluru, India
- SciGenom Labs Pvt. Ltd., Cochin, India
| | - Sivarama Prasad Lekkala
- AgriGenome Labs Pvt. Ltd., Biotechnology Incubation Center, MN iHub, Genome Valley, Hyderabad, India
| | - Lakshmi Mahadevan
- Medgenome Labs Ltd., Bengaluru, India
- SciGenom Labs Pvt. Ltd., Cochin, India
| | - Boney Kuriakose
- SciGenom Research Foundation, Cheruthuruthy, India
- AgriGenome Labs Pvt. Ltd., Kakkanad, India
| | - Navajeet Chakravartty
- AgriGenome Labs Pvt. Ltd., Biotechnology Incubation Center, MN iHub, Genome Valley, Hyderabad, India
| | - A. V. S. K. Mohan Katta
- AgriGenome Labs Pvt. Ltd., Biotechnology Incubation Center, MN iHub, Genome Valley, Hyderabad, India
| | - Sam Santhosh
- SciGenom Research Foundation, Cheruthuruthy, India
| | - Arjula R. Reddy
- Department of Plant Sciences, University of Hyderabad, Hyderabad, India
| | - George Thomas
- SciGenom Research Foundation, Cheruthuruthy, India
- AgriGenome Labs Pvt. Ltd., Kakkanad, India
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78
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Cui F, Brosché M, Shapiguzov A, He XQ, Vainonen JP, Leppälä J, Trotta A, Kangasjärvi S, Salojärvi J, Kangasjärvi J, Overmyer K. Interaction of methyl viologen-induced chloroplast and mitochondrial signalling in Arabidopsis. Free Radic Biol Med 2019; 134:555-566. [PMID: 30738155 DOI: 10.1016/j.freeradbiomed.2019.02.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/05/2019] [Accepted: 02/05/2019] [Indexed: 01/20/2023]
Abstract
Reactive oxygen species (ROS) are key signalling intermediates in plant metabolism, defence, and stress adaptation. In plants, both the chloroplast and mitochondria are centres of metabolic control and ROS production, which coordinate stress responses in other cell compartments. The herbicide and experimental tool, methyl viologen (MV) induces ROS generation in the chloroplast under illumination, but is also toxic in non-photosynthetic organisms. We used MV to probe plant ROS signalling in compartments other than the chloroplast. Taking a genetic approach in the model plant Arabidopsis (Arabidopsis thaliana), we used natural variation, QTL mapping, and mutant studies with MV in the light, but also under dark conditions, when the chloroplast electron transport is inactive. These studies revealed a light-independent MV-induced ROS-signalling pathway, suggesting mitochondrial involvement. Mitochondrial Mn SUPEROXIDE DISMUTASE was required for ROS-tolerance and the effect of MV was enhanced by exogenous sugar, providing further evidence for the role of mitochondria. Mutant and hormone feeding assays revealed roles for stress hormones in organellar ROS-responses. The radical-induced cell death1 mutant, which is tolerant to MV-induced ROS and exhibits altered mitochondrial signalling, was used to probe interactions between organelles. Our studies suggest that mitochondria are involved in the response to ROS induced by MV in plants.
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Affiliation(s)
- Fuqiang Cui
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland
| | - Mikael Brosché
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland; Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia
| | - Alexey Shapiguzov
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland; Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, 127276, Moscow, Russia
| | - Xin-Qiang He
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland; College of Life Sciences, Peking University, Beijing, 100871, China
| | - Julia P Vainonen
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland
| | - Johanna Leppälä
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland
| | - Andrea Trotta
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Saijaliisa Kangasjärvi
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Jarkko Salojärvi
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland; School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
| | - Jaakko Kangasjärvi
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland
| | - Kirk Overmyer
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland.
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79
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Coolen S, Van Pelt JA, Van Wees SCM, Pieterse CMJ. Mining the natural genetic variation in Arabidopsis thaliana for adaptation to sequential abiotic and biotic stresses. PLANTA 2019; 249:1087-1105. [PMID: 30547240 DOI: 10.1007/s00425-018-3065-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 12/05/2018] [Indexed: 05/24/2023]
Abstract
In this genome-wide association study, we obtained novel insights into the genetic basis of the effect of herbivory or drought stress on the level of resistance against the fungus Botrytis cinerea. In nature, plants function in complex environments where they encounter different biotic and abiotic stresses individually, sequentially or simultaneously. The adaptive response to a single stress does not always reflect how plants respond to such a stress in combination with other stresses. To identify genetic factors that contribute to the plant's ability to swiftly adapt to different stresses, we investigated the response of Arabidopsis thaliana to infection by the necrotrophic fungus B. cinerea when preceded by Pieris rapae herbivory or drought stress. Using 346 natural A. thaliana accessions, we found natural genetic variation in the level of resistance against single B. cinerea infection. When preceded by herbivory or drought stress, the level of B. cinerea resistance was differentially influenced in the 346 accessions. To study the genetic factors contributing to the differential adaptation of A. thaliana to B. cinerea infection under multi-stress conditions, we performed a genome-wide association study supported by quantitative trait loci mapping and fine mapping with full genome sequences of 164 accessions. This yielded several genes previously associated with defense to B. cinerea and additional candidate genes with putative roles in the plant's adaptive response to a combination of herbivory, drought and B. cinerea infection.
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Affiliation(s)
- Silvia Coolen
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, PO Box 80056, 3508 TB, Utrecht, The Netherlands
| | - Johan A Van Pelt
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, PO Box 80056, 3508 TB, Utrecht, The Netherlands
| | - Saskia C M Van Wees
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, PO Box 80056, 3508 TB, Utrecht, The Netherlands
| | - Corné M J Pieterse
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, PO Box 80056, 3508 TB, Utrecht, The Netherlands.
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80
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How Linked Selection Shapes the Diversity Landscape in Ficedula Flycatchers. Genetics 2019; 212:277-285. [PMID: 30872320 PMCID: PMC6499528 DOI: 10.1534/genetics.119.301991] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/07/2019] [Indexed: 12/19/2022] Open
Abstract
There is an increasing awareness that selection affecting linked neutral sites strongly influences on how diversity is distributed across the genome. In particular, linked selection is likely involved in the formation of heterogenous landscapes of genetic diversity, including genomic regions with locally reduced effective population sizes that manifest as dips in diversity, and "islands" of differentiation between closely related populations or species. Linked selection can be in the form of background selection or selective sweeps, and a long-standing quest in population genetics has been to unveil the relative importance of these processes. Here, we analyzed the theoretically expected reduction of diversity caused by linked selection in the collared flycatcher (Ficedula albicollis) genome and compared this with population genomic data on the distribution of diversity across the flycatcher genome. By incorporating data on recombination rate variation and the density of target sites for selection (including both protein-coding genes and conserved noncoding elements), we found that background selection can explain most of the observed baseline variation in genetic diversity. However, positive selection was necessary to explain the pronounced local diversity dips in the collared flycatcher genome. We confirmed our analytical findings by comprehensive simulations. Therefore, our study demonstrates that even though both background selection and selective sweeps contribute to the heterogeneous diversity landscape seen in this avian system, they play different roles in shaping it.
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81
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Parallel colonization of subalpine habitats in the central European mountains by Primula elatior. Sci Rep 2019; 9:3294. [PMID: 30824749 PMCID: PMC6397301 DOI: 10.1038/s41598-019-39669-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 01/30/2019] [Indexed: 12/15/2022] Open
Abstract
The island-like distribution of subalpine habitats across mountain ranges can trigger the parallel evolution of locally adapted ecotypes. Such naturally replicated scenarios allow testing hypotheses on how elevational differentiation structures genetic diversity within species. Nevertheless, the parallel colonization of subalpine habitats across different mountain ranges has only rarely been documented with molecular data. We chose Primula elatior (Primulaceae), naturally spanning entire elevation range in multiple mountain regions of central Europe, to test for the origin of its scattered subalpine populations. Nuclear microsatellite variation revealed three genetic groups corresponding with the distinct study regions. We found that genetic differentiation between foothill and subalpine populations within each region was relatively low, suggesting that the colonization of subalpine habitats occurred independently within each mountain range. Furthermore, the strongest differentiation was usually found between the subalpine populations suggesting that mountain ridges may act as migration barriers that can reduce gene flow more strongly than elevational differences between foothill and subalpine populations. Finally, we found that subalpine colonization did not result in a loss of genetic diversity relative to foothill populations in agreement with the high migration rates that we document here between the subalpine and the foothill populations. In summary, our study shows subalpine Primula elatior populations are genetically diverse and distinct results of parallel colonization events from multiple foothill gene pools.
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82
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Pervasive population genomic consequences of genome duplication in Arabidopsis arenosa. Nat Ecol Evol 2019; 3:457-468. [DOI: 10.1038/s41559-019-0807-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 01/10/2019] [Indexed: 12/30/2022]
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83
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Silva-Junior OB, Grattapaglia D, Novaes E, Collevatti RG. Design and evaluation of a sequence capture system for genome-wide SNP genotyping in highly heterozygous plant genomes: a case study with a keystone Neotropical hardwood tree genome. DNA Res 2019; 25:535-545. [PMID: 30020434 PMCID: PMC6191306 DOI: 10.1093/dnares/dsy023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 06/22/2018] [Indexed: 12/12/2022] Open
Abstract
Targeted sequence capture coupled to high-throughput sequencing has become a powerful method for the study of genome-wide sequence variation. Following our recent development of a genome assembly for the Pink Ipê tree (Handroanthus impetiginosus), a widely distributed Neotropical timber species, we now report the development of a set of 24,751 capture probes for single-nucleotide polymorphisms (SNPs) characterization and genotyping across 18,216 distinct loci, sampling more than 10 Mbp of the species genome. This system identifies nearly 200,000 SNPs located inside or in close proximity to almost 14,000 annotated protein-coding genes, generating quality genotypic data in populations spanning wide geographic distances across the species native range. To provide recommendations for future developments of similar systems for highly heterozygous plant genomes we investigated issues such as probe design, sequencing coverage and bioinformatics, including the evaluation of the capture efficiency and a reassessment of the technical reproducibility of the assay for SNPs recall and genotyping precision. Our results highlight the value of a detailed probe screening on a preliminary genome assembly to produce reliable data for downstream genetic studies. This work should inspire and assist the development of similar genomic resources for other orphan crops and forest trees with highly heterozygous genomes.
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Affiliation(s)
- Orzenil Bonfim Silva-Junior
- EMBRAPA Recursos Genéticos e Biotecnologia, EPqB, Brasília, DF, Brazil.,Programa de Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, SGAN 916 Modulo B, Brasilia, DF, Brazil
| | - Dario Grattapaglia
- EMBRAPA Recursos Genéticos e Biotecnologia, EPqB, Brasília, DF, Brazil.,Programa de Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, SGAN 916 Modulo B, Brasilia, DF, Brazil
| | - Evandro Novaes
- Departamento de Biologia, Universidade Federal de Lavras, Lavras, MG, Brazil
| | - Rosane G Collevatti
- Laboratório de Genética & Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil
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84
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Wang Z, Ma LY, Cao J, Li YL, Ding LN, Zhu KM, Yang YH, Tan XL. Recent Advances in Mechanisms of Plant Defense to Sclerotinia sclerotiorum. FRONTIERS IN PLANT SCIENCE 2019; 10:1314. [PMID: 31681392 PMCID: PMC6813280 DOI: 10.3389/fpls.2019.01314] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/20/2019] [Indexed: 05/20/2023]
Abstract
Sclerotinia sclerotiorum (Lib.) de Bary is an unusual pathogen which has the broad host range, diverse infection modes, and potential double feeding lifestyles of both biotroph and necrotroph. It is capable of infecting over 400 plant species found worldwide and more than 60 names have agriculturally been used to refer to diseases caused by this pathogen. Plant defense to S. sclerotiorum is a complex biological process and exhibits a typical quantitative disease resistance (QDR) response. Recent studies using Arabidopsis thaliana and crop plants have obtained new advances in mechanisms used by plants to cope with S. sclerotiorum infection. In this review, we focused on our current understanding on plant defense mechanisms against this pathogen, and set up a model for the defense process including three stages: recognition of this pathogen, signal transduction and defense response. We also have a particular interest in defense signaling mediated by diverse signaling molecules. We highlight the current challenges and unanswered questions in both the defense process and defense signaling. Essentially, we discussed candidate resistance genes newly mapped by using high-throughput experiments in important crops, and classified these potential gene targets into different stages of the defense process, which will broaden our understanding of the genetic architecture underlying quantitative resistance to S. sclerotiorum. We proposed that more powerful mapping population(s) will be required for accurate and reliable QDR gene identification.
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85
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Bamba M, Kawaguchi YW, Tsuchimatsu T. Plant adaptation and speciation studied by population genomic approaches. Dev Growth Differ 2018; 61:12-24. [DOI: 10.1111/dgd.12578] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 10/22/2018] [Accepted: 10/22/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Masaru Bamba
- Department of Biology (Frontier Science Program); Graduate School of Science and Engineering; Chiba University; Chiba Japan
| | - Yawako W. Kawaguchi
- Department of Biology (Frontier Science Program); Graduate School of Science and Engineering; Chiba University; Chiba Japan
| | - Takashi Tsuchimatsu
- Department of Biology; Graduate School of Science; Chiba University; Chiba Japan
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86
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Wei X, Zhang J. The optimal mating distance resulting from heterosis and genetic incompatibility. SCIENCE ADVANCES 2018; 4:eaau5518. [PMID: 30417098 PMCID: PMC6221538 DOI: 10.1126/sciadv.aau5518] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/10/2018] [Indexed: 05/30/2023]
Abstract
Theory predicts that the fitness of an individual is maximized when the genetic distance between its parents (i.e., mating distance) is neither too small nor too large. However, decades of research have generally failed to validate this prediction or identify the optimal mating distance (OMD). Respectively analyzing large numbers of crosses of fungal, plant, and animal model organisms, we indeed find the hybrid phenotypic value a humped quadratic polynomial function of the mating distance for the vast majority of fitness-related traits examined, with different traits of the same species exhibiting similar OMDs. OMDs are generally slightly greater than the nucleotide diversities of the species concerned but smaller than the observed maximal intraspecific genetic distances. Hence, the benefit of heterosis is at least partially offset by the harm of genetic incompatibility even within species. These results have multiple theoretical and practical implications for speciation, conservation, and agriculture.
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87
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Cornejo OE, Yee MC, Dominguez V, Andrews M, Sockell A, Strandberg E, Livingstone D, Stack C, Romero A, Umaharan P, Royaert S, Tawari NR, Ng P, Gutierrez O, Phillips W, Mockaitis K, Bustamante CD, Motamayor JC. Population genomic analyses of the chocolate tree, Theobroma cacao L., provide insights into its domestication process. Commun Biol 2018; 1:167. [PMID: 30345393 PMCID: PMC6191438 DOI: 10.1038/s42003-018-0168-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 09/14/2018] [Indexed: 01/24/2023] Open
Abstract
Domestication has had a strong impact on the development of modern societies. We sequenced 200 genomes of the chocolate plant Theobroma cacao L. to show for the first time to our knowledge that a single population, the Criollo population, underwent strong domestication ~3600 years ago (95% CI: 2481-13,806 years ago). We also show that during the process of domestication, there was strong selection for genes involved in the metabolism of the colored protectants anthocyanins and the stimulant theobromine, as well as disease resistance genes. Our analyses show that domesticated populations of T. cacao (Criollo) maintain a higher proportion of high-frequency deleterious mutations. We also show for the first time the negative consequences of the increased accumulation of deleterious mutations during domestication on the fitness of individuals (significant reduction in kilograms of beans per hectare per year as Criollo ancestry increases, as estimated from a GLM, P = 0.000425).
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Affiliation(s)
- Omar E Cornejo
- School of Biological Sciences, Washington State University, PO Box 644236, Heald Hall 429B, Pullman, Washington, 99164, USA
- Department of Genetics, School of Medicine, Stanford University, 300 Pasteur Dr. Lane Bldg Room L331, Stanford, CA, 94305, USA
| | - Muh-Ching Yee
- Department of Genetics, School of Medicine, Stanford University, 300 Pasteur Dr. Lane Bldg Room L331, Stanford, CA, 94305, USA
- Stanford Functional Genomics Facility, Stanford, CA, 94305, USA
| | - Victor Dominguez
- Department of Biology, Indiana University, 915 E. Third St, Bloomington, IN, 47405, USA
| | - Mary Andrews
- Department of Biology, Indiana University, 915 E. Third St, Bloomington, IN, 47405, USA
| | - Alexandra Sockell
- Department of Genetics, School of Medicine, Stanford University, 300 Pasteur Dr. Lane Bldg Room L331, Stanford, CA, 94305, USA
| | - Erika Strandberg
- Department of Genetics, School of Medicine, Stanford University, 300 Pasteur Dr. Lane Bldg Room L331, Stanford, CA, 94305, USA
- Biomedical Informatics Training Program, 1265 Welch Road, MSOB, X-215, MC 5479, Stanford, CA, 94305-5479, USA
| | - Donald Livingstone
- Mars, Incorporated, 6885 Elm Street, McLean, VA, 22101, USA
- United States Department of Agriculture-Agriculture Research Service, Subtropical Horticulture Research Station, 13601 Old Cutler Rd, Miami, FL, 33158, USA
| | - Conrad Stack
- Mars, Incorporated, 6885 Elm Street, McLean, VA, 22101, USA
| | - Alberto Romero
- Mars, Incorporated, 6885 Elm Street, McLean, VA, 22101, USA
| | - Pathmanathan Umaharan
- Cocoa Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - Stefan Royaert
- Mars, Incorporated, 6885 Elm Street, McLean, VA, 22101, USA
| | - Nilesh R Tawari
- Computational and Systems Biology, Genome Institute of Singapore, 60 Biopolis Street, Genome, #02-01, Singapore, 138672, Singapore
| | - Pauline Ng
- Computational and Systems Biology, Genome Institute of Singapore, 60 Biopolis Street, Genome, #02-01, Singapore, 138672, Singapore
| | - Osman Gutierrez
- SHRS, USDS-ARS, 13601 Old Cutler Road, Miami, FL, 33158, USA
| | - Wilbert Phillips
- Programa de Mejoramiento de Cacao, CATIE, 7170, Turrialba, Costa Rica
| | - Keithanne Mockaitis
- Department of Biology, Indiana University, 915 E. Third St, Bloomington, IN, 47405, USA
- Pervasive Technology Institute, Indiana University, 2709 E. 10th St., Bloomington, IN, 47408, USA
| | - Carlos D Bustamante
- Department of Genetics, School of Medicine, Stanford University, 300 Pasteur Dr. Lane Bldg Room L331, Stanford, CA, 94305, USA
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88
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Proietti S, Caarls L, Coolen S, Van Pelt JA, Van Wees SC, Pieterse CM. Genome-wide association study reveals novel players in defense hormone crosstalk in Arabidopsis. PLANT, CELL & ENVIRONMENT 2018; 41:2342-2356. [PMID: 29852537 PMCID: PMC6175328 DOI: 10.1111/pce.13357] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/04/2018] [Accepted: 05/18/2018] [Indexed: 05/22/2023]
Abstract
Jasmonic acid (JA) regulates plant defenses against necrotrophic pathogens and insect herbivores. Salicylic acid (SA) and abscisic acid (ABA) can antagonize JA-regulated defenses, thereby modulating pathogen or insect resistance. We performed a genome-wide association (GWA) study on natural genetic variation in Arabidopsis thaliana for the effect of SA and ABA on the JA pathway. We treated 349 Arabidopsis accessions with methyl JA (MeJA), or a combination of MeJA and either SA or ABA, after which expression of the JA-responsive marker gene PLANT DEFENSIN1.2 (PDF1.2) was quantified as a readout for GWA analysis. Both hormones antagonized MeJA-induced PDF1.2 in the majority of the accessions but with a large variation in magnitude. GWA mapping of the SA- and ABA-affected PDF1.2 expression data revealed loci associated with crosstalk. GLYI4 (encoding a glyoxalase) and ARR11 (encoding an Arabidopsis response regulator involved in cytokinin signalling) were confirmed by T-DNA insertion mutant analysis to affect SA-JA crosstalk and resistance against the necrotroph Botrytis cinerea. In addition, At1g16310 (encoding a cation efflux family protein) was confirmed to affect ABA-JA crosstalk and susceptibility to Mamestra brassicae herbivory. Collectively, this GWA study identified novel players in JA hormone crosstalk with potential roles in the regulation of pathogen or insect resistance.
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Affiliation(s)
- Silvia Proietti
- Plant‐Microbe Interactions, Department of Biology, Science4LifeUtrecht UniversityUtrechtThe Netherlands
| | - Lotte Caarls
- Plant‐Microbe Interactions, Department of Biology, Science4LifeUtrecht UniversityUtrechtThe Netherlands
| | - Silvia Coolen
- Plant‐Microbe Interactions, Department of Biology, Science4LifeUtrecht UniversityUtrechtThe Netherlands
| | - Johan A. Van Pelt
- Plant‐Microbe Interactions, Department of Biology, Science4LifeUtrecht UniversityUtrechtThe Netherlands
| | - Saskia C.M. Van Wees
- Plant‐Microbe Interactions, Department of Biology, Science4LifeUtrecht UniversityUtrechtThe Netherlands
| | - Corné M.J. Pieterse
- Plant‐Microbe Interactions, Department of Biology, Science4LifeUtrecht UniversityUtrechtThe Netherlands
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89
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Song K, Li L, Zhang G. Relationship Among Intron Length, Gene Expression, and Nucleotide Diversity in the Pacific Oyster Crassostrea gigas. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2018; 20:676-684. [PMID: 29967965 DOI: 10.1007/s10126-018-9838-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
Crassostrea gigas is a model mollusk, but its genetic features have not been studied comprehensively. In this study, we used whole-genome resequencing data to identify and characterize nucleotide diversity and population recombination rate in a diverse collection of 21 C. gigas samples. Our analyses revealed that C. gigas harbors both extremely high genetic diversity and recombination rates across the whole genome as compared with those of the other taxa. The noncoding regions, introns, intergenic spacers, and untranslated regions (UTRs) showed a lower level diversity than the synonymous sites. The larger introns tended to have lower diversity. Moreover, we found a negative association of the non-synonymous diversity with gene expression, which suggested that purifying selection played an important role in shaping genetic diversity. The nucleotide diversity at the 100- and 50-kb levels was positively correlated with population recombination rates, which was expected if the diversity was shaped by purifying selection or hitchhiking of advantageous mutants. Our work gives a general picture of the oyster's polymorphism pattern and its association with recombination rates.
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Affiliation(s)
- Kai Song
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, Shandong, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, Shandong, China
- National & Local Joint Engineering Laboratory of Ecological Mariculture, Qingdao, 266071, Shandong, China
| | - Li Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, Shandong, China.
- National & Local Joint Engineering Laboratory of Ecological Mariculture, Qingdao, 266071, Shandong, China.
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, Shandong, China.
- Institute of Oceanology, Chinese Academy of Sciences, 7th Nanhai Rd., Qingdao, China.
| | - Guofan Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, Shandong, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, Shandong, China.
- National & Local Joint Engineering Laboratory of Ecological Mariculture, Qingdao, 266071, Shandong, China.
- Institute of Oceanology, Chinese Academy of Sciences, 7th Nanhai Rd., Qingdao, China.
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90
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Paape T, Briskine RV, Halstead-Nussloch G, Lischer HEL, Shimizu-Inatsugi R, Hatakeyama M, Tanaka K, Nishiyama T, Sabirov R, Sese J, Shimizu KK. Patterns of polymorphism and selection in the subgenomes of the allopolyploid Arabidopsis kamchatica. Nat Commun 2018; 9:3909. [PMID: 30254374 PMCID: PMC6156220 DOI: 10.1038/s41467-018-06108-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 08/10/2018] [Indexed: 12/30/2022] Open
Abstract
Genome duplication is widespread in wild and crop plants. However, little is known about genome-wide selection in polyploids due to the complexity of duplicated genomes. In polyploids, the patterns of purifying selection and adaptive substitutions may be affected by masking owing to duplicated genes or homeologs as well as effective population size. Here, we resequence 25 accessions of the allotetraploid Arabidopsis kamchatica, which is derived from the diploid species A. halleri and A. lyrata. We observe a reduction in purifying selection compared with the parental species. Interestingly, proportions of adaptive non-synonymous substitutions are significantly positive in contrast to most plant species. A recurrent pattern observed in both frequency and divergence–diversity neutrality tests is that the genome-wide distributions of both subgenomes are similar, but the correlation between homeologous pairs is low. This may increase the opportunity of different evolutionary trajectories such as in the HMA4 gene involved in heavy metal hyperaccumulation. Despite the prevalence of genome duplication in plants, little is known about the evolutionary patterns of entire subgenomes. Here the authors resequence allopolyploid Arabidopsis kamchatica genome to estimate diversity, linkage disequilibrium and strengths of both positive and purifying selection.
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Affiliation(s)
- Timothy Paape
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland. .,Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland.
| | - Roman V Briskine
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.,Department of Environmental Systems Science, ETH Zurich, CH-8092, Zurich, Switzerland.,Functional Genomics Center Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Gwyneth Halstead-Nussloch
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Heidi E L Lischer
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.,Swiss Institute of Bioinformatics (SIB), Lausanne, 1015, Switzerland
| | - Rie Shimizu-Inatsugi
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.,Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland
| | - Masaomi Hatakeyama
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.,Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland.,Swiss Institute of Bioinformatics (SIB), Lausanne, 1015, Switzerland.,Functional Genomics Center Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Kenta Tanaka
- Sugadaira Montane Research Center, University of Tsukuba, Nagano, Ueda, 386-2204, Japan
| | - Tomoaki Nishiyama
- Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-0934, Japan
| | - Renat Sabirov
- Institute of Marine Geology and Geophysics, Far East Branch, Russian Academy of Sciences, Nauki street, 1-B, Yuzhno-Sakhalinsk, 693022, Russian Federation
| | - Jun Sese
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, 135-0064, Japan.,AIST-Tokyo Tech Real World Big-Data Computation Open Innovation Laboratory, Tokyo, 152-8550, Japan
| | - Kentaro K Shimizu
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland. .,Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, CH-8008, Zurich, Switzerland. .,Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Yokohama, 244-0813, Japan.
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91
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Chai C, Shankar R, Jain M, Subudhi PK. Genome-wide discovery of DNA polymorphisms by whole genome sequencing differentiates weedy and cultivated rice. Sci Rep 2018; 8:14218. [PMID: 30242197 PMCID: PMC6155081 DOI: 10.1038/s41598-018-32513-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 09/10/2018] [Indexed: 12/13/2022] Open
Abstract
Analyzing the genome level DNA polymorphisms between weedy and cultivated rice is crucial to elucidate the molecular basis of weedy and agronomic traits, which in turn can enhance our ability to control weedy rice and its utilization for rice improvement. Here, we presented the genome-wide genetic variations between a weedy rice accession PSRR-1 and two cultivated rice accessions, Bengal and Nona Bokra, belonging to japonica and indica subspecies, respectively. The total number of SNPs and InDels in PSRR/Bengal was similar to that of Nona Bokra/Bengal, but was three times greater than that of PSRR/Nona Bokra. There were 11546 large-effect SNPs/InDels affecting 5673 genes, which most likely differentiated weedy rice from cultivated rice. These large effect DNA polymorphisms were mostly resulted in stop codon gain and least by start codon loss. Analysis of the molecular functions and biological processes of weedy rice specific SNPs/InDels indicated that most of these genes were involved in protein modification/phosphorylation, protein kinase activity, and protein/nucleotide binding. By integrating previous QTL mapping results with the DNA polymorphisms data, the candidate genes for seed dormancy and seed shattering were narrowed down. The genomic resource generated in this study will facilitate discovery of functional variants for weedy and agronomic traits.
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Affiliation(s)
- Chenglin Chai
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, 70803, USA
- Noble Research Institute, LLC, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Rama Shankar
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Mukesh Jain
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Prasanta K Subudhi
- School of Plant, Environmental, and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, 70803, USA.
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92
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Fulgione A, Hancock AM. Archaic lineages broaden our view on the history of Arabidopsis thaliana. THE NEW PHYTOLOGIST 2018; 219:1194-1198. [PMID: 29862511 DOI: 10.1111/nph.15244] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/25/2018] [Indexed: 05/15/2023]
Abstract
Contents Summary 1194 I. Introduction 1194 II. Origin of the A. thaliana species 1194 III. The classic model of the history of A. thaliana 1195 IV. New genomic data from outside Eurasia challenge our view of A. thaliana history 1195 V. Conclusions 1197 Acknowledgements 1197 References 1197 SUMMARY: Natural variation in Arabidopsis thaliana has contributed to discoveries in diverse areas of plant biology. While A. thaliana has typically been considered a weed associated primarily with human-mediated environments, including agricultural and urban sites and railways, it has recently been shown that it is also native in remote natural areas, including high altitude sites in Eurasia and Africa, from the Atlas mountains in Morocco to the afro-alpine regions in Eastern and South Africa to Yunnan in China, the Himalayas and the Tibetan Plateau. This finding suggests that while A. thaliana has been extensively studied in Europe and Western Asia there are still many open questions about its population history, genotype-phenotype relationships and mechanisms of adaptation.
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Affiliation(s)
- Andrea Fulgione
- Max Planck Institute for Plant Breeding Research, 50829, Cologne, Germany
| | - Angela M Hancock
- Max Planck Institute for Plant Breeding Research, 50829, Cologne, Germany
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93
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Yu H, Shahid MQ, Li R, Li W, Liu W, Ghouri F, Liu X. Genome-Wide Analysis of Genetic Variations and the Detection of Rich Variants of NBS-LRR Encoding Genes in Common Wild Rice Lines. PLANT MOLECULAR BIOLOGY REPORTER 2018; 36:618-630. [PMID: 30363818 PMCID: PMC6182389 DOI: 10.1007/s11105-018-1103-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Common wild rice (Oryza rufipogon Griff.) is invaluable genetic resource for rice resistance breeding. Whole-genome re-sequencing was conducted to systematically analyze the variations in two new inbred lines (Huaye 3 and Huaye 4) developed from a common wild rice. A total of 4,841,127 SNPs, 1,170,479 InDels, 24,080 structural variations (SVs), and 298 copy number variations (CNVs) were identified in three materials. Approximately 16.24 and 5.64% of the total SNPs and InDels of Huaye 3 and Huaye 4 were located in genic regions, respectively. Together, 12,486 and 15,925 large-effect SNPs, and 12,417 and 14,513 large-effect InDels, which affect the integrity of the encoded protein, were identified in Huaye 3 and Huaye 4, respectively. The distribution map of 194 and 245 NBS-LRR encoding homologs was constructed across 12 rice chromosomes. Further, GO enrichment analysis of the homologs with identical genotype variations in Huaye 3 and Huaye 4 revealed 67, 82, and 58 homologs involved in cell death, response to stress, and both terms, respectively. Comparative analysis displayed that 550 out of 652 SNPs and 129 out of 147 InDels were present in a widely used blast-susceptible rice variety (LTH). Protein-protein interaction analysis revealed a strong interaction between NBS-LRR candidates and several known R genes. One homolog of disease resistance protein (RPM1) was involved in the plant-pathogen interaction pathway. Artificial inoculation of disease/insect displayed resistance phenotypes against rice blast and brown planthopper in two lines. The results will provide allele-specific markers for rice molecular breeding.
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Affiliation(s)
- Hang Yu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Muhammad Qasim Shahid
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Rongbai Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004 China
| | - Wei Li
- College of Agronomy, Guangdong Ocean University, Zhanjiang, 524000 China
| | - Wen Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642 China
- Department of Tropical Crops, Guangdong Agriculture Industry Business Polytechnic College, Guangzhou, 510507 China
| | - Fozia Ghouri
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642 China
| | - Xiangdong Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642 China
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94
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Press MO, McCoy RC, Hall AN, Akey JM, Queitsch C. Massive variation of short tandem repeats with functional consequences across strains of Arabidopsis thaliana. Genome Res 2018; 28:1169-1178. [PMID: 29970452 PMCID: PMC6071631 DOI: 10.1101/gr.231753.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 06/26/2018] [Indexed: 11/24/2022]
Abstract
Short tandem repeat (STR) mutations may comprise more than half of the mutations in eukaryotic coding DNA, yet STR variation is rarely examined as a contributor to complex traits. We assessed this contribution across a collection of 96 strains of Arabidopsis thaliana, genotyping 2046 STR loci each, using highly parallel STR sequencing with molecular inversion probes. We found that 95% of examined STRs are polymorphic, with a median of six alleles per STR across these strains. STR expansions (large copy number increases) are found in most strains, several of which have evident functional effects. These include three of six intronic STR expansions we found to be associated with intron retention. Coding STRs were depleted of variation relative to noncoding STRs, and we detected a total of 56 coding STRs (11%) showing low variation consistent with the action of purifying selection. In contrast, some STRs show hypervariable patterns consistent with diversifying selection. Finally, we detected 133 novel STR-phenotype associations under stringent criteria, most of which could not be detected with SNPs alone, and validated some with follow-up experiments. Our results support the conclusion that STRs constitute a large, unascertained reservoir of functionally relevant genomic variation.
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Affiliation(s)
- Maximilian O Press
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Rajiv C McCoy
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Ashley N Hall
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA.,Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98195, USA
| | - Joshua M Akey
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
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95
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Rajarammohan S, Pradhan AK, Pental D, Kaur J. Genome-wide association mapping in Arabidopsis identifies novel genes underlying quantitative disease resistance to Alternaria brassicae. MOLECULAR PLANT PATHOLOGY 2018; 19:1719-1732. [PMID: 29271603 PMCID: PMC6638106 DOI: 10.1111/mpp.12654] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 05/19/2023]
Abstract
Quantitative disease resistance (QDR) is the predominant form of resistance against necrotrophic pathogens. The genes and mechanisms underlying QDR are not well known. In the current study, the Arabidopsis-Alternaria brassicae pathosystem was used to uncover the genetic architecture underlying resistance to A. brassicae in a set of geographically diverse Arabidopsis accessions. Arabidopsis accessions revealed a rich variation in the host responses to the pathogen, varying from complete resistance to high susceptibility. Genome-wide association (GWA) mapping revealed multiple regions to be associated with disease resistance. A subset of genes prioritized on the basis of gene annotations and evidence of transcriptional regulation in other biotic stresses was analysed using a reverse genetics approach employing T-DNA insertion mutants. The mutants of three genes, namely At1g06990 (GDSL-motif lipase), At3g25180 (CYP82G1) and At5g37500 (GORK), displayed an enhanced susceptibility relative to the wild-type. These genes are involved in the development of morphological phenotypes (stomatal aperture) and secondary metabolite synthesis, thus defining some of the diverse facets of quantitative resistance against A. brassicae.
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Affiliation(s)
| | - Akshay Kumar Pradhan
- Department of GeneticsUniversity of Delhi South CampusNew Delhi110021India
- Centre for Genetic Manipulation of Crop PlantsUniversity of Delhi South CampusNew Delhi110021India
| | - Deepak Pental
- Centre for Genetic Manipulation of Crop PlantsUniversity of Delhi South CampusNew Delhi110021India
| | - Jagreet Kaur
- Department of GeneticsUniversity of Delhi South CampusNew Delhi110021India
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96
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Ali J, Aslam UM, Tariq R, Murugaiyan V, Schnable PS, Li D, Marfori-Nazarea CM, Hernandez JE, Arif M, Xu J, Li Z. Exploiting the Genomic Diversity of Rice ( Oryza sativa L.): SNP-Typing in 11 Early-Backcross Introgression-Breeding Populations. FRONTIERS IN PLANT SCIENCE 2018; 9:849. [PMID: 29988489 PMCID: PMC6024854 DOI: 10.3389/fpls.2018.00849] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/31/2018] [Indexed: 05/24/2023]
Abstract
This study demonstrates genotyping-by-sequencing-based single-nucleotide polymorphism (SNP)-typing in 11 early-backcross introgression populations of rice (at BC1F5), comprising a set of 564 diverse introgression lines and 12 parents. Sequencing using 10 Ion Proton runs generated a total of ∼943.4 million raw reads, out of which ∼881.6 million reads remained after trimming for low-quality bases. After alignment, 794,297 polymorphic SNPs were identified, and filtering resulted in LMD50 SNPs (low missing data, with each SNP, genotyped in at least 50% of the samples) for each sub-population. Every data point was supported by actual sequencing data without any imputation, eliminating imputation-induced errors in SNP calling. Genotyping substantiated the impacts of novel breeding strategy revealing: (a) the donor introgression patterns in ILs were characteristic with variable introgression frequency in different genomic regions, attributed mainly to stringent selection under abiotic stress and (b) considerably lower heterozygosity was observed in ILs. Functional annotation revealed 426 non-synonymous deleterious SNPs present in 102 loci with a range of 1-4 SNPs per locus and 120 novel SNPs. SNP-typing this diversity panel will further assist in the development of markers supporting genomic applications in molecular breeding programs.
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Affiliation(s)
- Jauhar Ali
- International Rice Research Institute, Los Baños, Philippines
| | - Umair M. Aslam
- International Rice Research Institute, Los Baños, Philippines
- Institute of Crop Science, University of the Philippines Los Baños, Los Baños, Philippines
| | - Rida Tariq
- International Rice Research Institute, Los Baños, Philippines
- National Institute of Biotechnology and Genetic Engineering, Faisalabad, Pakistan
| | | | - Patrick S. Schnable
- Data2Bio, LLC, Ames, IA, United States
- Department of Agronomy, Iowa State University, Ames, IA, United States
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, China
| | - Delin Li
- Data2Bio, LLC, Ames, IA, United States
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, China
| | - Corinne M. Marfori-Nazarea
- International Rice Research Institute, Los Baños, Philippines
- Institute of Crop Science, University of the Philippines Los Baños, Los Baños, Philippines
| | - Jose E. Hernandez
- Institute of Crop Science, University of the Philippines Los Baños, Los Baños, Philippines
| | - Muhammad Arif
- National Institute of Biotechnology and Genetic Engineering, Faisalabad, Pakistan
| | - Jianlong Xu
- Department of Plant Genetics and Breeding, China Agricultural University, Beijing, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhikang Li
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
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97
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Wang XJ, Hu QJ, Guo XY, Wang K, Ru DF, German DA, Weretilnyk EA, Abbott RJ, Lascoux M, Liu JQ. Demographic expansion and genetic load of the halophyte model plantEutrema salsugineum. Mol Ecol 2018; 27:2943-2955. [DOI: 10.1111/mec.14738] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 05/16/2018] [Accepted: 05/24/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Xiao-Juan Wang
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education; College of Life Sciences; Sichuan University; Chengdu China
| | - Quan-Jun Hu
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education; College of Life Sciences; Sichuan University; Chengdu China
| | - Xin-Yi Guo
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education; College of Life Sciences; Sichuan University; Chengdu China
| | - Kun Wang
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education; College of Life Sciences; Sichuan University; Chengdu China
| | - Da-Fu Ru
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education; College of Life Sciences; Sichuan University; Chengdu China
| | - Dmitry A. German
- Department of Biodiversity and Plant Systematics; Centre for Organismal Studies (COS Heidelberg); Heidelberg University; Heidelberg Germany
- South-Siberian Botanical Garden; Altai State University; Barnaul Russia
| | | | | | - Martin Lascoux
- Department of Ecology and Genetics; Evolutionary Biology Center and Science for Life Laboratory; Uppsala University; Uppsala Sweden
| | - Jian-quan Liu
- Key Laboratory for Bio-resource and Eco-environment of Ministry of Education; College of Life Sciences; Sichuan University; Chengdu China
- State Key Laboratory of Grassland Agro-Ecosystem; College of Life Science; Lanzhou University; Lanzhou China
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98
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Toosi A, Fernando RL, Dekkers JCM. Genome-wide mapping of quantitative trait loci in admixed populations using mixed linear model and Bayesian multiple regression analysis. Genet Sel Evol 2018; 50:32. [PMID: 29914353 PMCID: PMC6006859 DOI: 10.1186/s12711-018-0402-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 06/01/2018] [Indexed: 12/18/2022] Open
Abstract
Background Population stratification and cryptic relationships have been the main sources of excessive false-positives and false-negatives in population-based association studies. Many methods have been developed to model these confounding factors and minimize their impact on the results of genome-wide association studies. In most of these methods, a two-stage approach is applied where: (1) methods are used to determine if there is a population structure in the sample dataset and (2) the effects of population structure are corrected either by modeling it or by running a separate analysis within each sub-population. The objective of this study was to evaluate the impact of population structure on the accuracy and power of genome-wide association studies using a Bayesian multiple regression method. Methods We conducted a genome-wide association study in a stochastically simulated admixed population. The genome was composed of six chromosomes, each with 1000 markers. Fifteen segregating quantitative trait loci contributed to the genetic variation of a quantitative trait with heritability of 0.30. The impact of genetic relationships and breed composition (BC) on three analysis methods were evaluated: single marker simple regression (SMR), single marker mixed linear model (MLM) and Bayesian multiple-regression analysis (BMR). Each method was fitted with and without BC. Accuracy, power, false-positive rate and the positive predictive value of each method were calculated and used for comparison. Results SMR and BMR, both without BC, were ranked as the worst and the best performing approaches, respectively. Our results showed that, while explicit modeling of genetic relationships and BC is essential for models SMR and MLM, BMR can disregard them and yet result in a higher power without compromising its false-positive rate. Conclusions This study showed that the Bayesian multiple-regression analysis is robust to population structure and to relationships among study subjects and performs better than a single marker mixed linear model approach.
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Affiliation(s)
- Ali Toosi
- Cobb-Vantress Inc., 4703 US HWY 412 E, Siloam Springs, AR, 72761, USA.
| | - Rohan L Fernando
- Department of Animal Science, Iowa State University, Ames, IA, 50010, USA
| | - Jack C M Dekkers
- Department of Animal Science, Iowa State University, Ames, IA, 50010, USA
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99
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Bahri BA, Daverdin G, Xu X, Cheng JF, Barry KW, Brummer EC, Devos KM. Natural variation in genes potentially involved in plant architecture and adaptation in switchgrass (Panicum virgatum L.). BMC Evol Biol 2018; 18:91. [PMID: 29898656 PMCID: PMC6000970 DOI: 10.1186/s12862-018-1193-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 05/15/2018] [Indexed: 11/24/2022] Open
Abstract
Background Advances in genomic technologies have expanded our ability to accurately and exhaustively detect natural genomic variants that can be applied in crop improvement and to increase our knowledge of plant evolution and adaptation. Switchgrass (Panicum virgatum L.), an allotetraploid (2n = 4× = 36) perennial C4 grass (Poaceae family) native to North America and a feedstock crop for cellulosic biofuel production, has a large potential for genetic improvement due to its high genotypic and phenotypic variation. In this study, we analyzed single nucleotide polymorphism (SNP) variation in 372 switchgrass genotypes belonging to 36 accessions for 12 genes putatively involved in biomass production to investigate signatures of selection that could have led to ecotype differentiation and to population adaptation to geographic zones. Results A total of 11,682 SNPs were mined from ~ 15 Gb of sequence data, out of which 251 SNPs were retained after filtering. Population structure analysis largely grouped upland accessions into one subpopulation and lowland accessions into two additional subpopulations. The most frequent SNPs were in homozygous state within accessions. Sixty percent of the exonic SNPs were non-synonymous and, of these, 45% led to non-conservative amino acid changes. The non-conservative SNPs were largely in linkage disequilibrium with one haplotype being predominantly present in upland accessions while the other haplotype was commonly present in lowland accessions. Tajima’s test of neutrality indicated that PHYB, a gene involved in photoperiod response, was under positive selection in the switchgrass population. PHYB carried a SNP leading to a non-conservative amino acid change in the PAS domain, a region that acts as a sensor for light and oxygen in signal transduction. Conclusions Several non-conservative SNPs in genes potentially involved in plant architecture and adaptation have been identified and led to population structure and genetic differentiation of ecotypes in switchgrass. We suggest here that PHYB is a key gene involved in switchgrass natural selection. Further analyses are needed to determine whether any of the non-conservative SNPs identified play a role in the differential adaptation of upland and lowland switchgrass. Electronic supplementary material The online version of this article (10.1186/s12862-018-1193-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bochra A Bahri
- Institute of Plant Breeding, Genetics and Genomics (Department of Crop and Soil Sciences), and Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA. .,Laboratory of Bioaggressors and Integrated Protection in Agriculture, The National Agronomic Institute of Tunisia, University of Carthage, 43 Avenue Charles-Nicolle, 1082, Tunis, Tunisia.
| | - Guillaume Daverdin
- Institute of Plant Breeding, Genetics and Genomics (Department of Crop and Soil Sciences), and Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA.,Present address: Vinson Edward Ltd, Faversham, ME13 8UP, UK
| | - Xiangyang Xu
- Institute of Plant Breeding, Genetics and Genomics (Department of Crop and Soil Sciences), and Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA.,Present address: USDA-ARS, Wheat, Peanut and Other Field Crops Research Unit, Stillwater, OK, 74075, USA
| | - Jan-Fang Cheng
- DOE Joint Genome Institute, Walnut Creek, California, CA, 94598, USA
| | - Kerrie W Barry
- DOE Joint Genome Institute, Walnut Creek, California, CA, 94598, USA
| | - E Charles Brummer
- Plant Breeding Center, Plant Sciences Department, University of California, Davis, CA, 95616, USA
| | - Katrien M Devos
- Institute of Plant Breeding, Genetics and Genomics (Department of Crop and Soil Sciences), and Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA
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100
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Gustafsson C, Willforss J, Lopes-Pinto F, Ortiz R, Geleta M. Identification of genes regulating traits targeted for domestication of field cress (Lepidium campestre) as a biennial and perennial oilseed crop. BMC Genet 2018; 19:36. [PMID: 29843613 PMCID: PMC5975587 DOI: 10.1186/s12863-018-0624-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 05/18/2018] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The changing climate and the desire to use renewable oil sources necessitate the development of new oilseed crops. Field cress (Lepidium campestre) is a species in the Brassicaceae family that has been targeted for domestication not only as an oilseed crop that produces seeds with a desirable industrial oil quality but also as a cover/catch crop that provides valuable ecosystem services. Lepidium is closely related to Arabidopsis and display significant proportions of syntenic regions in their genomes. Arabidopsis genes are among the most characterized genes in the plant kingdom and, hence, comparative genomics of Lepidium-Arabidopsis would facilitate the identification of Lepidium candidate genes regulating various desirable traits. RESULTS Homologues of 30 genes known to regulate vernalization, flowering time, pod shattering, oil content and quality in Arabidopsis were identified and partially characterized in Lepidium. Alignments of sequences representing field cress and two of its closely related perennial relatives: L. heterophyllum and L. hirtum revealed 243 polymorphic sites across the partial sequences of the 30 genes, of which 95 were within the predicted coding regions and 40 led to a change in amino acids of the target proteins. Within field cress, 34 polymorphic sites including nine non-synonymous substitutions were identified. The phylogenetic analysis of the data revealed that field cress is more closely related to L. heterophyllum than to L. hirtum. CONCLUSIONS There is significant variation within and among Lepidium species within partial sequences of the 30 genes known to regulate traits targeted in the present study. The variation within these genes are potentially useful to speed-up the process of domesticating field cress as future oil crop. The phylogenetic relationship between the Lepidium species revealed in this study does not only shed some light on Lepidium genome evolution but also provides important information to develop efficient schemes for interspecific hybridization between different Lepidium species as part of the domestication efforts.
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Affiliation(s)
- Cecilia Gustafsson
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Box 101, SE-23053, Alnarp, Sweden
| | - Jakob Willforss
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, SE-23053, Alnarp, Sweden
| | - Fernando Lopes-Pinto
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7023, SE-750 07, Uppsala, Sweden
| | - Rodomiro Ortiz
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Box 101, SE-23053, Alnarp, Sweden
| | - Mulatu Geleta
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Box 101, SE-23053, Alnarp, Sweden.
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