Author
Kelly Ivors
Other affiliations: Agricultural Research Service, Oregon State University, University of California, Berkeley
Bio: Kelly Ivors is an academic researcher from North Carolina State University. The author has contributed to research in topics: Phytophthora ramorum & Phytophthora. The author has an hindex of 23, co-authored 46 publications receiving 2918 citations. Previous affiliations of Kelly Ivors include Agricultural Research Service & Oregon State University.
Papers
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Virginia Tech1, Joint Genome Institute2, Lawrence Berkeley National Laboratory3, Wageningen University and Research Centre4, University of Warwick5, Imperial College London6, University of California, Berkeley7, Cornell University8, Ohio Agricultural Research and Development Center9, Agriculture and Agri-Food Canada10, Agricultural Research Service11, Lawrence Livermore National Laboratory12, North Carolina State University13, University of Tennessee14, Oak Ridge National Laboratory15, University of California, Merced16, University of Queensland17, Wilkes University18, Bowling Green State University19, Hokkaido University20
TL;DR: Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oömycete avirulence genes.
Abstract: Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oomycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oomycete avirulence genes.
1,016 citations
TL;DR: The combined microsatellite, sequencing and morphological analyses suggest the three clades identified in the genome sequence of Phytophthora ramorum represent distinct evolutionary lineages, emphasizing the role of commercial plant trade in the movement of this pathogen.
Abstract: Analysis of 12 polymorphic simple sequence repeats identified in the genome sequence of Phytophthora ramorum , causal agent of ‘sudden oak death’, revealed genotypic diversity to be significantly higher in nurseries (91% of total) than in forests (18% of total). Our analysis identified only two closely related genotypes in US forests, while the genetic structure of populations from European nurseries was of intermediate complexity, including multiple, closely related genotypes. Multilocus analysis determined populations in US forests reproduce clonally and are likely descendants of a single introduced individual. The 151 isolates analysed clustered in three clades. US forest and European nursery isolates clustered into two distinct clades, while one isolate from a US nursery belonged to a third novel clade. The combined microsatellite, sequencing and morphological analyses suggest the three clades represent distinct evolutionary lineages. All three clades were identified in some US nurseries, emphasizing the role of commercial plant trade in the movement of this pathogen.
220 citations
Thomas D. Bruns1, Meredith Blackwell2, Ivan P. Edwards3, Andy F. S. Taylor4 +252 more•Institutions (144)
TL;DR: GenBank, the public repository for nucleotide and protein sequences, is a critical resource for molecular biology, evolutionary biology, and ecology as discussed by the authors, and some attention has been drawn to sequence errors ([1][1]), common annotation errors also reduce the value of this database.
Abstract: GenBank, the public repository for nucleotide and protein sequences, is a critical resource for molecular biology, evolutionary biology, and ecology. While some attention has been drawn to sequence errors ([1][1]), common annotation errors also reduce the value of this database. In fact, for
210 citations
TL;DR: The past decade has seen an approximate doubling in the number of described species within the genus Phytophthora, and the number will likely continue to increase as more surveys are completed and greater attention is devoted to clarifying phylogenetic relationships and delineating boundaries in species complexes.
Abstract: With the increased attention given to the genus Phytophthora in the last decade in response to the ecological and economic impact of several invasive species (such as P. ramorum, P. kernoviae, and P. alni), there has been a significant increase in the number of described species. In part, this is due to the extensive surveys in historically underexplored ecosystems (e.g., forest and stream ecosystems) undertaken to determine the spread of invasive species and the involvement of Phytophthora species in forest decline worldwide (e.g., oak decline). The past decade has seen an approximate doubling in the number of described species within the genus Phytophthora, and the number will likely continue to increase as more surveys are completed and greater attention is devoted to clarifying phylogenetic relationships and delineating boundaries in species complexes. The development of molecular resources, the availability of credible sequence databases to simplify identification of new species, and the sequencing of several genomes have provided a solid framework to gain a better understanding of the biology, diversity, and taxonomic relationships within the genus. This information is much needed considering the impact invasive or exotic Phytophthora species have had on natural ecosystems and the regulatory issues associated with their management. While this work is improving our ability to identify species based on phylogenetic grouping, it has also revealed that the genus has a much greater diversity than previously appreciated.
199 citations
TL;DR: The genetic structure within and between USA and European populations of the emerging phytopathogen Phytophthora ramorum was examined, and phylogenetic analysis indicates that P. ramorum is closely related to P. lateralis and P. hibernalis.
181 citations
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American Museum of Natural History1, University of Tartu2, University of Gothenburg3, University of Aberdeen4, James Hutton Institute5, Cooperative Institute for Research in Environmental Sciences6, University of California, Berkeley7, Aberystwyth University8, Estonian University of Life Sciences9, Spanish National Research Council10, Royal Botanic Gardens11, Academy of Sciences of the Czech Republic12, Swedish University of Agricultural Sciences13, University of Tennessee14, University of Helsinki15, Stanford University16, Ludwig Maximilian University of Munich17, University of Toronto18, University of Florida19, University of New Mexico20, University of Tübingen21
TL;DR: All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type, and the term ‘species hypothesis’ (SH) is introduced for the taxa discovered in clustering on different similarity thresholds.
Abstract: The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third-party annotation effort. We introduce the term ‘species hypothesis’ (SH) for the taxa discovered in clustering on different similarity thresholds (97–99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web-based sequence management system in UNITE.
2,605 citations
TL;DR: Fungi typically live in highly diverse communities composed of multiple ecological guilds, and FUNGuild is a tool that can be used to taxonomically parse fungal OTUs by ecological guild independent of sequencing platform or analysis pipeline.
2,290 citations
École Normale Supérieure1, J. Craig Venter Institute2, Joint Genome Institute3, Alfred Wegener Institute for Polar and Marine Research4, University of Konstanz5, University of Wisconsin–Milwaukee6, University of Melbourne7, University of Washington8, University of Nantes9, University of Wisconsin-Madison10, Ghent University11, University of Rhode Island12, Sewanee: The University of the South13, University of Arizona14, Hebrew University of Jerusalem15, Georgia Institute of Technology16, Leibniz Institute for Neurobiology17, Stazione Zoologica Anton Dohrn18, University of British Columbia19, Stanford University20, Scottish Association for Marine Science21, University of North Carolina at Wilmington22
TL;DR: Analysis of molecular divergence compared with yeasts and metazoans reveals rapid rates of gene diversification in diatoms, and documents the presence of hundreds of genes from bacteria, likely to provide novel possibilities for metabolite management and for perception of environmental signals.
Abstract: Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one- fifth of the primary productivity on Earth(1,2). The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology(3-5). Here we report the complete genome sequence of the pennate diatom Phaeodactylum tricornutum and compare it with that of T. pseudonana to clarify evolutionary origins, functional significance and ubiquity of these features throughout diatoms. In spite of the fact that the pennate and centric lineages have only been diverging for 90 million years, their genome structures are dramatically different and a substantial fraction of genes (similar to 40%) are not shared by these representatives of the two lineages. Analysis of molecular divergence compared with yeasts and metazoans reveals rapid rates of gene diversification in diatoms. Contributing factors include selective gene family expansions, differential losses and gains of genes and introns, and differential mobilization of transposable elements. Most significantly, we document the presence of hundreds of genes from bacteria. More than 300 of these gene transfers are found in both diatoms, attesting to their ancient origins, and many are likely to provide novel possibilities for metabolite management and for perception of environmental signals. These findings go a long way towards explaining the incredible diversity and success of the diatoms in contemporary oceans.
1,500 citations
University of Tartu1, University of Gothenburg2, American Museum of Natural History3, University of Aberdeen4, Centraalbureau voor Schimmelcultures5, Max Planck Society6, University of Oslo7, University of Copenhagen8, Finnish Forest Research Institute9, Manchester Metropolitan University10, Macaulay Institute11, University of Washington12
1,471 citations
Broad Institute1, Ohio Agricultural Research and Development Center2, Sainsbury Laboratory3, Uppsala University4, Wageningen University and Research Centre5, Virginia Bioinformatics Institute6, University of California, Riverside7, University of Aberdeen8, Scottish Crop Research Institute9, University of Warwick10, Agricultural Research Service11, Royal Institute of Technology12, Cornell University13, Oregon State University14, Lafayette College15, University of Glasgow16, Harvard University17, Delaware Biotechnology Institute18, North Carolina State University19, University of Delaware20, University of Tennessee21, University of Maryland, Baltimore22, Vanderbilt University23, College of Wooster24, Bowling Green State University25, Edinburgh Cancer Research Centre26, J. Craig Venter Institute27, Tel Aviv University28, University of Wisconsin-Madison29, University of Hohenheim30, University of Dundee31
TL;DR: The sequence of the P. infestans genome is reported, which at ∼240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates and probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
Abstract: Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement(1). To this day, it affects world agriculture by causing the most destructive disease of potato, the fourth largest food crop and a critical alternative to the major cereal crops for feeding the world's population(1). Current annual worldwide potato crop losses due to late blight are conservatively estimated at $6.7 billion(2). Management of this devastating pathogen is challenged by its remarkable speed of adaptation to control strategies such as genetically resistant cultivars(3,4). Here we report the sequence of the P. infestans genome, which at similar to 240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates. Its expansion results from a proliferation of repetitive DNA accounting for similar to 74% of the genome. Comparison with two other Phytophthora genomes showed rapid turnover and extensive expansion of specific families of secreted disease effector proteins, including many genes that are induced during infection or are predicted to have activities that alter host physiology. These fast-evolving effector genes are localized to highly dynamic and expanded regions of the P. infestans genome. This probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
1,341 citations