Author
Anne E. Dorrance
Other affiliations: Washington State University, Ohio Agricultural Research and Development Center
Bio: Anne E. Dorrance is an academic researcher from Ohio State University. The author has contributed to research in topics: Phytophthora sojae & Population. The author has an hindex of 35, co-authored 138 publications receiving 4557 citations. Previous affiliations of Anne E. Dorrance include Washington State University & Ohio Agricultural Research and Development Center.
Papers published on a yearly basis
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
Mississippi State University1, University of Kentucky2, Iowa State University3, South Dakota State University4, Michigan State University5, University of Arkansas6, Pennsylvania State University7, Oklahoma State University–Stillwater8, Ohio State University9, University of Florida10, University of Costa Rica11, University of Maryland, College Park12, Louisiana State University13, Texas A&M University14, Kansas State University15, University of Tennessee16, University of Georgia17, University of Delaware18, North Carolina State University19, University of Minnesota20, North Dakota State University21, Virginia Tech22, Clemson University23, DuPont Pioneer24, Auburn University25, University of Wisconsin-Madison26, Ontario Ministry of the Environment27, Purdue University28, University of Missouri29
TL;DR: Annual decreases in corn yield caused by diseases were estimated by surveying members of the Corn Disease Working Group in 22 corn-producing states in the United States and in Ontario, Canada from 2012 through 2015 by finding foliar diseases commonly caused the largest estimated yield loss.
Abstract: Annual decreases in soybean (Glycine max L. Merrill) yield caused by diseases were estimated by surveying university-affiliated plant pathologists in 28 soybean-producing states in the United State...
181 citations
TL;DR: Using a strain-specific polymerase chain reaction assay under commercial conditions, it was demonstrated that introduced inoculum of T382 did not spread frequently from inoculated to control compost-amended media, and the low population of isolates that can induce systemic resistance in composting and potting mix environments may explain why most compost-AMended substrates do not naturally suppress foliar diseases.
Abstract: Several factors affect the ability of Trichoderma spp. to provide systemic disease control. This paper focuses on the role of the substrate in which plants are grown, resistance of the host to disease, and the ability of introduced Trichoderma inoculum to spread under commercial conditions. Several reports reveal that foliar disease control provided by Trichoderma spp. is more effective on plants grown in compost-amended media compared with in lower-in-microbial-carrying-capacity sphagnum peat media. In Rhododendron spp., host resistance affects control of Phytophthora dieback provided by Trichoderma spp. For example, T. hamatum 382 (T382) significantly (P = 0.05) suppressed the disease on susceptible cv. Roseum Elegans while plant vigor was increased. The disease was not suppressed, however, on highly susceptible cvs. Aglo and PJM Elite even though the vigor of these plants was increased. Using a strain-specific polymerase chain reaction assay under commercial conditions, it was demonstrated that introduced inoculum of T382 did not spread frequently from inoculated to control compost-amended media. Other Trichoderma isolates typically are abundant in control media within days after potting unless inoculated with a specific Trichoderma isolate. Thus, the low population of isolates that can induce systemic resistance in composting and potting mix environments may explain why most compost-amended substrates do not naturally suppress foliar diseases.
151 citations
TL;DR: Investigation of Pythium spp.
Abstract: Cool, moist conditions in combination with minimum tillage, earlier planting, and recent shifts in commercial fungicide seed-treatment active ingredients have led to an increase in corn (Zea mays) and soybean (Glycine max) seedling establishment problems. This situation resulted in an investigation of Pythium spp. associated with seed and seedling diseases. Samples of diseased corn and soybean seedlings were collected from 42 production fields in Ohio. All isolates of Pythium recovered were identified to species using morphological and molecular techniques and evaluated in an in vitro pathogenicity assay on both corn and soybean seed, and a subset of the isolates was tested for sensitivity to fungicides currently used as seed treatments. Eleven species and two distinct morphological groups of Pythium were identified, of which six species were moderately to highly pathogenic on corn seed and nine species were highly pathogenic on soybean seed. There was significant variation (P < 0.05) in sensitivity to mefenoxam, azoxystrobin, trifloxystrobin, and captan both across and within species. Multiple species of Pythium had the capacity to reduce germination of both corn and soybean seed. Results indicated that mefenoxam, azoxystrobin, trifloxystrobin, or captan, when used individually, may not inhibit all pathogenic species of Pythium found in Ohio soils.
145 citations
TL;DR: Results indicate that F. graminearum is an important pathogen of both corn and soybean seed and seedlings in Ohio, and that continued use of fludioxonil potentially may select for less sensitive isolates of F. GramInearum.
Abstract: Fusarium graminearum is an important pathogen of cereal crops in Ohio causing primarily head blight in wheat and stalk and ear rot of corn. During the springs of 2004 and 2005, 112 isolates of F. graminearum were recovered from diseased corn and soybean seedlings from 30 locations in 13 Ohio counties. These isolates were evaluated in an in vitro pathogenicity assay on both corn and soybean seed, and 28 isolates were tested for sensitivity to the seed treatment fungicides azoxystrobin, trifloxystrobin, fludioxonil, and captan. All of the isolates were highly pathogenic on corn seed and moderately to highly pathogenic on soybean seed. Fludioxonil was the only fungicide that provided sufficient inhibition of mycelial growth; however, several fludioxonil-resistant mutants were identified during the sensitivity experiments. These results indicate that F. graminearum is an important pathogen of both corn and soybean seed and seedlings in Ohio, and that continued use of fludioxonil potentially may select for less sensitive isolates of F. graminearum.
134 citations
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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
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
TL;DR: The number of well-supported cases of transfer from both prokaryotes and eukaryotes, many with significant functional implications, is now expanding rapidly and major recent trends include the important role of HGT in adaptation to certain specialized niches and the highly variable impact of H GT in different lineages.
Abstract: Horizontal gene transfer (HGT; also known as lateral gene transfer) has had an important role in eukaryotic genome evolution, but its importance is often overshadowed by the greater prevalence and our more advanced understanding of gene transfer in prokaryotes. Recurrent endosymbioses and the generally poor sampling of most nuclear genes from diverse lineages have also complicated the search for transferred genes. Nevertheless, the number of well-supported cases of transfer from both prokaryotes and eukaryotes, many with significant functional implications, is now expanding rapidly. Major recent trends include the important role of HGT in adaptation to certain specialized niches and the highly variable impact of HGT in different lineages.
1,185 citations
TL;DR: A better understanding of molecular factors involved in this complex tripartite interaction is expected to enhance not only the rapid identification of effective strains and their applications but also indicate the potentials for improvement of natural strains of Trichoderma.
Abstract: Biological control involves the use of beneficial organisms, their genes, and/or products, such as metabolites, that reduce the negative effects of plant pathogens and promote positive responses by the plant. Disease suppression, as mediated by biocontrol agents, is the consequence of the interactions between the plant, pathogens, and the microbial community. Antagonists belonging to the genus Trichoderma are among the most commonly isolated soil fungi. Due to their ability to protect plants and contain pathogen populations under different soil conditions, these fungi have been widely studied and commercially marketed as biopesticides, biofertilizers and soil amendments. Trichoderma spp. also produce numerous biologically active compounds, including cell wall degrading enzymes, and secondary metabolites. Studies of the three-way relationship established with Trichoderma, the plant and the pathogen are aimed at unravelling the mechanisms involved in partner recognition and the cross-talk used to maintain the beneficial association between the fungal antagonist and the plant. Several strategies have been used to identify the molecular factors involved in this complex tripartite interaction including genomics, proteomics and, more recently, metabolomics, in order to enhance our understanding. This review presents recent advances and findings regarding the biocontrol-resulting events that take place during the Trichoderma –plant–pathogen interaction. We focus our attention on the biological aspects of this topic, highlighting the novel findings concerning the role of Trichoderma in disease suppression. A better understanding of these factors is expected to enhance not only the rapid identification of effective strains and their applications but also indicate the potentials for improvement of natural strains of Trichoderma .
1,079 citations
TL;DR: Functional analyses of two motifs, RXLR and EER, present in translocated oomycete effectors are reported, showing that RXLR-EER-encoding genes are transcriptionally upregulated during infection and 425 potential genes encoding secreted RXLR/EER class proteins in the P. infestans genome are identified.
Abstract: Bacterial, oomycete and fungal plant pathogens establish disease by translocation of effector proteins into host cells, where they may directly manipulate host innate immunity. In bacteria, translocation is through the type III secretion system, but analogous processes for effector delivery are uncharacterized in fungi and oomycetes. Here we report functional analyses of two motifs, RXLR and EER, present in translocated oomycete effectors. We use the Phytophthora infestans RXLR-EER-containing protein Avr3a as a reporter for translocation because it triggers RXLR-EER-independent hypersensitive cell death following recognition within plant cells that contain the R3a resistance protein. We show that Avr3a, with or without RXLR-EER motifs, is secreted from P. infestans biotrophic structures called haustoria, demonstrating that these motifs are not required for targeting to haustoria or for secretion. However, following replacement of Avr3a RXLR-EER motifs with alanine residues, singly or in combination, or with residues KMIK-DDK--representing a change that conserves physicochemical properties of the protein--P. infestans fails to deliver Avr3a or an Avr3a-GUS fusion protein into plant cells, demonstrating that these motifs are required for translocation. We show that RXLR-EER-encoding genes are transcriptionally upregulated during infection. Bioinformatic analysis identifies 425 potential genes encoding secreted RXLR-EER class proteins in the P. infestans genome. Identification of this class of proteins provides unparalleled opportunities to determine how oomycetes manipulate hosts to establish infection.
758 citations