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Lu M, Cao M, Yang J, Swenson NG. Comparative transcriptomics reveals divergence in pathogen response gene families amongst 20 forest tree species. G3 (BETHESDA, MD.) 2023; 13:jkad233. [PMID: 37812763 PMCID: PMC10700026 DOI: 10.1093/g3journal/jkad233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023]
Abstract
Forest trees provide critical ecosystem services for humanity that are under threat due to ongoing global change. Measuring and characterizing genetic diversity are key to understanding adaptive potential and developing strategies to mitigate negative consequences arising from climate change. In the area of forest genetic diversity, genetic divergence caused by large-scale changes at the chromosomal level has been largely understudied. In this study, we used the RNA-seq data of 20 co-occurring forest trees species from genera including Acer, Alnus, Amelanchier, Betula, Cornus, Corylus, Dirca, Fraxinus, Ostrya, Populus, Prunus, Quercus, Ribes, Tilia, and Ulmus sampled from Upper Peninsula of Michigan. These data were used to infer the origin and maintenance of gene family variation, species divergence time, as well as gene family expansion and contraction. We identified a signal of common whole genome duplication events shared by core eudicots. We also found rapid evolution, namely fast expansion or fast contraction of gene families, in plant-pathogen interaction genes amongst the studied diploid species. Finally, the results lay the foundation for further research on the genetic diversity and adaptive capacity of forest trees, which will inform forest management and conservation policies.
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Affiliation(s)
- Mengmeng Lu
- Department of Biological Sciences, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN 46556, USA
| | - Min Cao
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Jie Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Nathan G Swenson
- Department of Biological Sciences, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN 46556, USA
- University of Notre Dame Environmental Research Center (UNDERC), 736 Flanner Hall, Notre Dame, IN 46556, USA
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2
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Mesarich CH, Barnes I, Bradley EL, de la Rosa S, de Wit PJGM, Guo Y, Griffiths SA, Hamelin RC, Joosten MHAJ, Lu M, McCarthy HM, Schol CR, Stergiopoulos I, Tarallo M, Zaccaron AZ, Bradshaw RE. Beyond the genomes of Fulvia fulva (syn. Cladosporium fulvum) and Dothistroma septosporum: New insights into how these fungal pathogens interact with their host plants. MOLECULAR PLANT PATHOLOGY 2023; 24:474-494. [PMID: 36790136 PMCID: PMC10098069 DOI: 10.1111/mpp.13309] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 05/03/2023]
Abstract
Fulvia fulva and Dothistroma septosporum are closely related apoplastic pathogens with similar lifestyles but different hosts: F. fulva is a pathogen of tomato, whilst D. septosporum is a pathogen of pine trees. In 2012, the first genome sequences of these pathogens were published, with F. fulva and D. septosporum having highly fragmented and near-complete assemblies, respectively. Since then, significant advances have been made in unravelling their genome architectures. For instance, the genome of F. fulva has now been assembled into 14 chromosomes, 13 of which have synteny with the 14 chromosomes of D. septosporum, suggesting these pathogens are even more closely related than originally thought. Considerable advances have also been made in the identification and functional characterization of virulence factors (e.g., effector proteins and secondary metabolites) from these pathogens, thereby providing new insights into how they promote host colonization or activate plant defence responses. For example, it has now been established that effector proteins from both F. fulva and D. septosporum interact with cell-surface immune receptors and co-receptors to activate the plant immune system. Progress has also been made in understanding how F. fulva and D. septosporum have evolved with their host plants, whilst intensive research into pandemics of Dothistroma needle blight in the Northern Hemisphere has shed light on the origins, migration, and genetic diversity of the global D. septosporum population. In this review, we specifically summarize advances made in our understanding of the F. fulva-tomato and D. septosporum-pine pathosystems over the last 10 years.
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Affiliation(s)
- Carl H Mesarich
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
- Bioprotection Aotearoa, Massey University, Palmerston North, New Zealand
| | - Irene Barnes
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Ellie L Bradley
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Silvia de la Rosa
- Laboratory of Molecular Plant Pathology, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Pierre J G M de Wit
- Laboratory of Phytopathology, Wageningen University, Wageningen, Netherlands
| | - Yanan Guo
- Bioprotection Aotearoa, Massey University, Palmerston North, New Zealand
- Laboratory of Molecular Plant Pathology, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | | | - Richard C Hamelin
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, Québec, Canada
| | | | - Mengmeng Lu
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Hannah M McCarthy
- Laboratory of Molecular Plant Pathology, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Christiaan R Schol
- Laboratory of Phytopathology, Wageningen University, Wageningen, Netherlands
- Plant Breeding, Wageningen University & Research, Wageningen, Netherlands
| | - Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, California, USA
| | - Mariana Tarallo
- Laboratory of Molecular Plant Pathology, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Alex Z Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, California, USA
| | - Rosie E Bradshaw
- Bioprotection Aotearoa, Massey University, Palmerston North, New Zealand
- Laboratory of Molecular Plant Pathology, School of Natural Sciences, Massey University, Palmerston North, New Zealand
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Cox MP, Guo Y, Winter DJ, Sen D, Cauldron NC, Shiller J, Bradley EL, Ganley AR, Gerth ML, Lacey RF, McDougal RL, Panda P, Williams NM, Grunwald NJ, Mesarich CH, Bradshaw RE. Chromosome-level assembly of the Phytophthora agathidicida genome reveals adaptation in effector gene families. Front Microbiol 2022; 13:1038444. [PMID: 36406440 PMCID: PMC9667082 DOI: 10.3389/fmicb.2022.1038444] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/11/2022] [Indexed: 01/25/2023] Open
Abstract
Phytophthora species are notorious plant pathogens, with some causing devastating tree diseases that threaten the survival of their host species. One such example is Phytophthora agathidicida, the causal agent of kauri dieback - a root and trunk rot disease that kills the ancient, iconic and culturally significant tree species, Agathis australis (New Zealand kauri). A deeper understanding of how Phytophthora pathogens infect their hosts and cause disease is critical for the development of effective treatments. Such an understanding can be gained by interrogating pathogen genomes for effector genes, which are involved in virulence or pathogenicity. Although genome sequencing has become more affordable, the complete assembly of Phytophthora genomes has been problematic, particularly for those with a high abundance of repetitive sequences. Therefore, effector genes located in repetitive regions could be truncated or missed in a fragmented genome assembly. Using a combination of long-read PacBio sequences, chromatin conformation capture (Hi-C) and Illumina short reads, we assembled the P. agathidicida genome into ten complete chromosomes, with a genome size of 57 Mb including 34% repeats. This is the first Phytophthora genome assembled to chromosome level and it reveals a high level of syntenic conservation with the complete genome of Peronospora effusa, the only other completely assembled genome sequence of an oomycete. All P. agathidicida chromosomes have clearly defined centromeres and contain candidate effector genes such as RXLRs and CRNs, but in different proportions, reflecting the presence of gene family clusters. Candidate effector genes are predominantly found in gene-poor, repeat-rich regions of the genome, and in some cases showed a high degree of duplication. Analysis of candidate RXLR effector genes that occur in multicopy gene families indicated half of them were not expressed in planta. Candidate CRN effector gene families showed evidence of transposon-mediated recombination leading to new combinations of protein domains, both within and between chromosomes. Further analysis of this complete genome assembly will help inform new methods of disease control against P. agathidicida and other Phytophthora species, ultimately helping decipher how Phytophthora pathogens have evolved to shape their effector repertoires and how they might adapt in the future.
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Affiliation(s)
- Murray P. Cox
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Yanan Guo
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - David J. Winter
- Institute of Environmental Science and Research (ESR), Porirua, New Zealand
| | | | - Nicholas C. Cauldron
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | | | - Ellie L. Bradley
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Austen R. Ganley
- School of Biological Sciences and Digital Life Institute, University of Auckland, Auckland, New Zealand
| | - Monica L. Gerth
- Bioprotection Aotearoa, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Randy F. Lacey
- Bioprotection Aotearoa, School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | | | | | | | - Niklaus J. Grunwald
- Horticultural Crops Disease and Pest Management Research Unit, USDA Agricultural Research Service, Corvallis, OR, United States
| | - Carl H. Mesarich
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Rosie E. Bradshaw
- Laboratory of Molecular Plant Pathology/Bioprotection Aotearoa, School of Natural Sciences, Massey University, Palmerston North, New Zealand
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Jasper RJ, McDonald TK, Singh P, Lu M, Rougeux C, Lind BM, Yeaman S. Evaluating the accuracy of variant calling methods using the frequency of parent-offspring genotype mismatch. Mol Ecol Resour 2022; 22:2524-2533. [PMID: 35510784 PMCID: PMC9544674 DOI: 10.1111/1755-0998.13628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 03/11/2022] [Accepted: 03/29/2022] [Indexed: 11/28/2022]
Abstract
The use of next‐generation sequencing (NGS) data sets has increased dramatically over the last decade, but there have been few systematic analyses quantifying the accuracy of the commonly used variant caller programs. Here we used a familial design consisting of diploid tissue from a single lodgepole pine (Pinus contorta) parent and the maternally derived haploid tissue from 106 full‐sibling offspring, where mismatches could only arise due to mutation or bioinformatic error. Given the rarity of mutation, we used the rate of mismatches between parent and offspring genotype calls to infer the single nucleotide polymorphism (SNP) genotyping error rates of FreeBayes, HaplotypeCaller, SAMtools, UnifiedGenotyper, and VarScan. With baseline filtering HaplotypeCaller and UnifiedGenotyper yielded more SNPs and higher error rates by one to two orders of magnitude, whereas FreeBayes, SAMtools and VarScan yielded lower numbers of SNPs and more modest error rates. To facilitate comparison between variant callers we standardized each SNP set to the same number of SNPs using additional filtering, where UnifiedGenotyper consistently produced the smallest proportion of genotype errors, followed by HaplotypeCaller, VarScan, SAMtools, and FreeBayes. Additionally, we found that error rates were minimized for SNPs called by more than one variant caller. Finally, we evaluated the performance of various commonly used filtering metrics on SNP calling. Our analysis provides a quantitative assessment of the accuracy of five widely used variant calling programs and offers valuable insights into both the choice of variant caller program and the choice of filtering metrics, especially for researchers using non‐model study systems.
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Affiliation(s)
- Russ J Jasper
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | | | - Pooja Singh
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.,Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.,3EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Mengmeng Lu
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Clément Rougeux
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Brandon M Lind
- Centre for Forest Conservation Genetics and Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Sam Yeaman
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
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Hunziker L, Tarallo M, Gough K, Guo M, Hargreaves C, Loo TS, McDougal RL, Mesarich CH, Bradshaw RE. Apoplastic effector candidates of a foliar forest pathogen trigger cell death in host and non-host plants. Sci Rep 2021; 11:19958. [PMID: 34620932 PMCID: PMC8497623 DOI: 10.1038/s41598-021-99415-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/22/2021] [Indexed: 11/23/2022] Open
Abstract
Forests are under threat from pests, pathogens, and changing climate. A major forest pathogen worldwide is the hemibiotroph Dothistroma septosporum, which causes dothistroma needle blight (DNB) of pines. While D. septosporum uses effector proteins to facilitate host infection, it is currently unclear whether any of these effectors are recognised by immune receptors to activate the host immune system. Such information is needed to identify and select disease resistance against D. septosporum in pines. We predicted and investigated apoplastic D. septosporum candidate effectors (DsCEs) using bioinformatics and plant-based experiments. We discovered DsCEs that trigger cell death in the angiosperm Nicotiana spp., indicative of a hypersensitive defence response and suggesting their recognition by immune receptors in non-host plants. In a first for foliar forest pathogens, we developed a novel protein infiltration method to show that tissue-cultured pine shoots can respond with a cell death response to a DsCE, as well as to a reference cell death-inducing protein. The conservation of responses across plant taxa suggests that knowledge of pathogen-angiosperm interactions may also be relevant to pathogen-gymnosperm interactions. These results contribute to our understanding of forest pathogens and may ultimately provide clues to disease immunity in both commercial and natural forests.
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Affiliation(s)
- Lukas Hunziker
- Centre for Crop and Disease Management, Curtin University, Bentley, Perth, 6102, Australia
| | - Mariana Tarallo
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand
| | - Keiko Gough
- Scion, New Zealand Forest Research Institute Ltd, Rotorua, 3010, New Zealand
| | - Melissa Guo
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand
| | - Cathy Hargreaves
- Scion, New Zealand Forest Research Institute Ltd, Rotorua, 3010, New Zealand
| | - Trevor S Loo
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand
| | - Rebecca L McDougal
- Scion, New Zealand Forest Research Institute Ltd, Rotorua, 3010, New Zealand
| | - Carl H Mesarich
- Bio-Protection Research Centre, School of Agriculture and Environment, Massey University, Palmerston North, 4474, New Zealand
| | - Rosie E Bradshaw
- Bio-Protection Research Centre, School of Fundamental Sciences, Massey University, Palmerston North, 4474, New Zealand.
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