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Wilkinson SW, Hannan Parker A, Muench A, Wilson RS, Hooshmand K, Henderson MA, Moffat EK, Rocha PSCF, Hipperson H, Stassen JHM, López Sánchez A, Fomsgaard IS, Krokene P, Mageroy MH, Ton J. Long-lasting memory of jasmonic acid-dependent immunity requires DNA demethylation and ARGONAUTE1. Nat Plants 2023; 9:81-95. [PMID: 36604579 DOI: 10.1038/s41477-022-01313-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 11/10/2022] [Indexed: 06/17/2023]
Abstract
Stress can have long-lasting impacts on plants. Here we report the long-term effects of the stress hormone jasmonic acid (JA) on the defence phenotype, transcriptome and DNA methylome of Arabidopsis. Three weeks after transient JA signalling, 5-week-old plants retained induced resistance (IR) against herbivory but showed increased susceptibility to pathogens. Transcriptome analysis revealed long-term priming and/or upregulation of JA-dependent defence genes but repression of ethylene- and salicylic acid-dependent genes. Long-term JA-IR was associated with shifts in glucosinolate composition and required MYC2/3/4 transcription factors, RNA-directed DNA methylation, the DNA demethylase ROS1 and the small RNA (sRNA)-binding protein AGO1. Although methylome analysis did not reveal consistent changes in DNA methylation near MYC2/3/4-controlled genes, JA-treated plants were specifically enriched with hypomethylated ATREP2 transposable elements (TEs). Epigenomic characterization of mutants and transgenic lines revealed that ATREP2 TEs are regulated by RdDM and ROS1 and produce 21 nt sRNAs that bind to nuclear AGO1. Since ATREP2 TEs are enriched with sequences from IR-related defence genes, our results suggest that AGO1-associated sRNAs from hypomethylated ATREP2 TEs trans-regulate long-lasting memory of JA-dependent immunity.
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Affiliation(s)
- S W Wilkinson
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK.
| | - A Hannan Parker
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - A Muench
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - R S Wilson
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - K Hooshmand
- Department of Agroecology, Aarhus University, Slagelse, Denmark
| | - M A Henderson
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - E K Moffat
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - P S C F Rocha
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - H Hipperson
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - J H M Stassen
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - A López Sánchez
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK
| | - I S Fomsgaard
- Department of Agroecology, Aarhus University, Slagelse, Denmark
| | - P Krokene
- Division for Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research (NIBIO), Ås, Norway
| | - M H Mageroy
- Division for Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research (NIBIO), Ås, Norway
| | - J Ton
- Plants, Photosynthesis and Soil, School of Biosciences, Institute for Sustainable Food, The University of Sheffield, Sheffield, UK.
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Hipperson H, Dunning LT, Baker WJ, Butlin RK, Hutton I, Papadopulos AST, Smadja CM, Wilson TC, Devaux C, Savolainen V. Ecological speciation in sympatric palms: 2. Pre- and post-zygotic isolation. J Evol Biol 2016; 29:2143-2156. [PMID: 27374779 PMCID: PMC5096058 DOI: 10.1111/jeb.12933] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/27/2016] [Accepted: 06/30/2016] [Indexed: 01/22/2023]
Abstract
We evaluated reproductive isolation in two species of palms (Howea) that have evolved sympatrically on Lord Howe Island (LHI, Australia). We estimated the strength of some pre- and post-zygotic mechanisms in maintaining current species boundaries. We found that flowering time displacement between species is consistent across in and ex situ common gardens and is thus partly genetically determined. On LHI, pre-zygotic isolation due solely to flowering displacement was 97% for Howea belmoreana and 80% for H. forsteriana; this asymmetry results from H. forsteriana flowering earlier than H. belmoreana and being protandrous. As expected, only a few hybrids (here confirmed by genotyping) at both juvenile and adult stages could be detected in two sites on LHI, in which the two species grow intermingled (the Far Flats) or adjacently (Transit Hill). Yet, the distribution of hybrids was different between sites. At Transit Hill, we found no hybrid adult trees, but 13.5% of younger palms examined there were of late hybrid classes. In contrast, we found four hybrid adult trees, mostly of late hybrid classes, and only one juvenile F1 hybrid in the Far Flats. This pattern indicates that selection acts against hybrids between the juvenile and adult stages. An in situ reciprocal seed transplant between volcanic and calcareous soils also shows that early fitness components (up to 36 months) were affected by species and soil. These results are indicative of divergent selection in reproductive isolation, although it does not solely explain the current distribution of the two species on LHI.
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Affiliation(s)
- H Hipperson
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, UK
| | - L T Dunning
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, UK
| | - W J Baker
- Royal Botanic Gardens, Kew, Richmond, UK
| | - R K Butlin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
- Sven Lovén Centre for Marine Sciences, Tjärnö, University of Gothenburg, Stromstäd, Sweden
| | - I Hutton
- Lord Howe Island Museum, Lord Howe Island, NSW, Australia
| | - A S T Papadopulos
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, UK
- Royal Botanic Gardens, Kew, Richmond, UK
| | - C M Smadja
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, UK
| | - T C Wilson
- Royal Botanic Gardens and Domain Trust, Sydney, NSW, Australia
| | | | - V Savolainen
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, UK.
- Royal Botanic Gardens, Kew, Richmond, UK.
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Dunning LT, Hipperson H, Baker WJ, Butlin RK, Devaux C, Hutton I, Igea J, Papadopulos AST, Quan X, Smadja CM, Turnbull CGN, Savolainen V. Ecological speciation in sympatric palms: 1. Gene expression, selection and pleiotropy. J Evol Biol 2016; 29:1472-87. [PMID: 27177130 PMCID: PMC6680112 DOI: 10.1111/jeb.12895] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 05/04/2016] [Accepted: 05/11/2016] [Indexed: 02/02/2023]
Abstract
Ecological speciation requires divergent selection, reproductive isolation and a genetic mechanism to link the two. We examined the role of gene expression and coding sequence evolution in this process using two species of Howea palms that have diverged sympatrically on Lord Howe Island, Australia. These palms are associated with distinct soil types and have displaced flowering times, representing an ideal candidate for ecological speciation. We generated large amounts of RNA‐Seq data from multiple individuals and tissue types collected on the island from each of the two species. We found that differentially expressed loci as well as those with divergent coding sequences between Howea species were associated with known ecological and phenotypic differences, including response to salinity, drought, pH and flowering time. From these loci, we identified potential ‘ecological speciation genes’ and further validate their effect on flowering time by knocking out orthologous loci in a model plant species. Finally, we put forward six plausible ecological speciation loci, providing support for the hypothesis that pleiotropy could help to overcome the antagonism between selection and recombination during speciation with gene flow.
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Affiliation(s)
- L T Dunning
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - H Hipperson
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - W J Baker
- Royal Botanic Gardens, Kew, Richmond, UK
| | - R K Butlin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.,Sven Lovén Centre for Marine Sciences, Tjärnö, University of Gothenburg, Stromstäd, Sweden
| | - C Devaux
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - I Hutton
- Lord Howe Island Museum, Lord Howe Island, NSW, Australia
| | - J Igea
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - A S T Papadopulos
- Department of Life Sciences, Imperial College London, Ascot, UK.,Royal Botanic Gardens, Kew, Richmond, UK
| | - X Quan
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - C M Smadja
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - C G N Turnbull
- Department of Life Sciences, Imperial College London, London, UK
| | - V Savolainen
- Department of Life Sciences, Imperial College London, Ascot, UK.,Royal Botanic Gardens, Kew, Richmond, UK
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Whitlock R, Hipperson H, Mannarelli M, Butlin RK, Burke T. An objective, rapid and reproducible method for scoring AFLP peak-height data that minimizes genotyping error. Mol Ecol Resour 2013; 8:725-35. [PMID: 21585880 DOI: 10.1111/j.1755-0998.2007.02073.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Amplified fragment length polymorphism (AFLP) fingerprint data are now commonly collected using DNA sequencers. AFLP genotypes are still often scored by eye from such data - a time-consuming, error-prone and subjective process. We present a semi-automated method of genotyping sequencer-collected AFLPs at predefined fragment locations (loci) within the fingerprint. Our method uses thresholds of AFLP-polymerase chain reaction-product fluorescence intensity (peak height) in order to: (i) exclude AFLP loci that are likely to contribute high rates of error to data sets, and (ii) determine the AFLP phenotype (fragment presence or absence) at the retained loci. Error rate analysis is an integral part of this process and is used to determine optimal thresholds that minimize genotyping error, while maximizing the numbers of retained loci. We show that application of this method to a large AFLP data set allows genotype calls that are rapid, objective and repeatable, facilitating the extraction of reliable genotype data for molecular ecological studies.
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Affiliation(s)
- R Whitlock
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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Papadopulos AST, Price Z, Devaux C, Hipperson H, Smadja CM, Hutton I, Baker WJ, Butlin RK, Savolainen V. A comparative analysis of the mechanisms underlying speciation on Lord Howe Island. J Evol Biol 2013; 26:733-45. [PMID: 23320532 DOI: 10.1111/jeb.12071] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/07/2012] [Accepted: 11/08/2012] [Indexed: 11/29/2022]
Abstract
On Lord Howe Island, speciation is thought to have taken place in situ in a diverse array of distantly related plant taxa (Metrosideros, Howea and Coprosma; Proc. Natl Acad. Sci. USA 108, 2011, 13188). We now investigate whether the speciation processes were driven by divergent natural selection in each genus by examining the extent of ecological and genetic divergence. We present new and extensive, ecological and genetic data for all three genera. Consistent with ecologically driven speciation, outlier loci were detected using genome scan methods. This mechanism is supported by individual-based analyses of genotype-environment correlations within species, demonstrating that local adaptation is currently widespread on the island. Genetic analyses show that prezygotic isolating barriers within species are currently insufficiently strong to allow further population differentiation. Interspecific hybridization was found in both Howea and Coprosma, and species distribution modelling indicates that competitive exclusion may result in selection against admixed individuals. Colonization of new niches, partly fuelled by the rapid generation of new adaptive genotypes via hybridization, appears to have resulted in the adaptive radiation in Coprosma - supporting the 'Syngameon hypothesis'.
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