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2. Phytophthora ramorum

Author

Everhart, Sydney E., Tabima, Javier F., Grünwald, Niklaus J., Dean, Ralph A., editor, Lichens-Park, Ann, editor, and Kole, Chittaranjan, editor

Published
2014
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10. Diverse Evolutionary Trajectories for Small RNA Biogenesis Genes in the Oomycete Genus Phytophthora

Author

Bollmann, Stephanie R., Fang, Yufeng, Press, Caroline M., Tyler, Brett M., and Gruenwald, Niklaus J.

Subjects
Phytophthora, dicer, RDR, fungi, evolution, food and beverages, small RNA, stramenopile
Abstract

Gene regulation by small RNA pathways is ubiquitous among eukaryotes, but little is known about small RNA pathways in the Stramenopile kingdom. Phytophthora a genus of filamentous oomycetes, contains many devastating plant pathogens, causing multibillion-dollar damage to crops, ornamental plants, and natural environments. The genomes of several oomycetes including Phytophthora species such as the soybean pathogen P. sojae, have been sequenced, allowing evolutionary analysis of small RNA-processing enzymes. This study examined the evolutionary origins of the oomycete small RNA-related genes Dicer-like (DCL), and RNA-dependent RNA polymerase (RDR) through broad phylogenetic analyses of the key domains. Two Dicer gene homologs, DCL1 and DCL2, and one RDR homolog were cloned and analyzed from P sojae. Gene expression analysis revealed only minor changes in transcript levels among different life stages. Oomycete DCL1 homologs clustered with animal and plant Dicer homologs in evolutionary trees, whereas oomycete DCL2 homologs clustered basally to the tree along with Drosha homologs. Phylogenetic analysis of the RDR homologs confirmed a previous study that suggested the last common eukaryote ancestor possessed three RDR homologs, which were selectively retained or lost in later lineages. Our analysis clarifies the position of some Unikont and Chromalveolate RDR lineages within the tree, including oomycete homologs. Finally, we analyzed alterations in the domain structure of oomycete Dicer and RDR homologs, specifically focusing on the proposed domain transfer of the DEAD-box helicase domain from Dicer to RDR. Implications of the oomycete domain structure are discussed, and possible roles of the two oomycete Dicer homologs are proposed. USDA National Research Initiative [2008-35600-18780] USDA Agricultural Research Service (CRIS) [5358-22000-03900D] This work was supported by the USDA National Research Initiative (grant number 2008-35600-18780); and the USDA Agricultural Research Service (CRIS number 5358-22000-03900D).

Published
2016

11. Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans

Author

Haas, Brian J., Kamoun, Sophien, Zody, Michael C., Jiang, Rays H. Y., Handsaker, Robert E., Cano, Liliana M., Grabherr, Manfred, Kodira, Chinnappa D., Raffaele, Sylvain, Torto-Alalibo, Trudy, Bozkurt, Tolga O., Ah-Fong, Audrey M. V., Alvarado, Lucia, Anderson, Vicky L., Armstrong, Miles R., Avrova, Anna, Baxter, Laura, Beynon, Jim, Boevink, Petra C., Bollmann, Stephanie R., Bos, Jorunn I. B., Bulone, Vincent, Cai, Guohong, Cakir, Cahid, Carrington, James C., Chawner, Megan, Conti, Lucio, Costanzo, Stefano, Ewan, Richard, Fahlgren, Noah, Fischbach, Michael A., Fugelstad, Johanna, Gilroy, Eleanor M., Gnerre, Sante, Green, Pamela J., Grenville-Briggs, Laura J., Griffith, John, Gruenwald, Niklaus J., Horn, Karolyn, Horner, Neil R., Hu, Chia-Hui, Huitema, Edgar, Jeong, Dong-Hoon, Jones, Alexandra M. E., Jones, Jonathan D. G., Jones, Richard W., Karlsson, Elinor K., Kunjeti, Sridhara G., Lamour, Kurt, Liu, Zhenyu, Ma, LiJun, MacLean, Daniel, Chibucos, Marcus C., McDonald, Hayes, McWalters, Jessica, Meijer, Harold J. G., Morgan, William, Morris, Paul F., Munro, Carol A., O'Neill, Keith, Ospina-Giraldo, Manuel, Pinzon, Andres, Pritchard, Leighton, Ramsahoye, Bernard, Ren, Qinghu, Restrepo, Silvia, Roy, Sourav, Sadanandom, Ari, Savidor, Alon, Schornack, Sebastian, Schwartz, David C., Schumann, Ulrike D., Schwessinger, Ben, Seyer, Lauren, Sharpe, Ted, Silvar, Cristina, Song, Jing, Studholme, David J., Sykes, Sean, Thines, Marco, van de Vondervoort, Peter J. I., Phuntumart, Vipaporn, Wawra, Stephan, Weide, Rob, Win, Joe, Young, Carolyn, Zhou, Shiguo, Fry, William, Meyers, Blake C., van West, Pieter, Ristaino, Jean, Govers, Francine, Birch, Paul R. J., Whisson, Stephen C., Judelson, Howard S., Nusbaum, Chad, Haas, Brian J., Kamoun, Sophien, Zody, Michael C., Jiang, Rays H. Y., Handsaker, Robert E., Cano, Liliana M., Grabherr, Manfred, Kodira, Chinnappa D., Raffaele, Sylvain, Torto-Alalibo, Trudy, Bozkurt, Tolga O., Ah-Fong, Audrey M. V., Alvarado, Lucia, Anderson, Vicky L., Armstrong, Miles R., Avrova, Anna, Baxter, Laura, Beynon, Jim, Boevink, Petra C., Bollmann, Stephanie R., Bos, Jorunn I. B., Bulone, Vincent, Cai, Guohong, Cakir, Cahid, Carrington, James C., Chawner, Megan, Conti, Lucio, Costanzo, Stefano, Ewan, Richard, Fahlgren, Noah, Fischbach, Michael A., Fugelstad, Johanna, Gilroy, Eleanor M., Gnerre, Sante, Green, Pamela J., Grenville-Briggs, Laura J., Griffith, John, Gruenwald, Niklaus J., Horn, Karolyn, Horner, Neil R., Hu, Chia-Hui, Huitema, Edgar, Jeong, Dong-Hoon, Jones, Alexandra M. E., Jones, Jonathan D. G., Jones, Richard W., Karlsson, Elinor K., Kunjeti, Sridhara G., Lamour, Kurt, Liu, Zhenyu, Ma, LiJun, MacLean, Daniel, Chibucos, Marcus C., McDonald, Hayes, McWalters, Jessica, Meijer, Harold J. G., Morgan, William, Morris, Paul F., Munro, Carol A., O'Neill, Keith, Ospina-Giraldo, Manuel, Pinzon, Andres, Pritchard, Leighton, Ramsahoye, Bernard, Ren, Qinghu, Restrepo, Silvia, Roy, Sourav, Sadanandom, Ari, Savidor, Alon, Schornack, Sebastian, Schwartz, David C., Schumann, Ulrike D., Schwessinger, Ben, Seyer, Lauren, Sharpe, Ted, Silvar, Cristina, Song, Jing, Studholme, David J., Sykes, Sean, Thines, Marco, van de Vondervoort, Peter J. I., Phuntumart, Vipaporn, Wawra, Stephan, Weide, Rob, Win, Joe, Young, Carolyn, Zhou, Shiguo, Fry, William, Meyers, Blake C., van West, Pieter, Ristaino, Jean, Govers, Francine, Birch, Paul R. J., Whisson, Stephen C., Judelson, Howard S., and Nusbaum, Chad

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.

Published
2009
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14. Population History and Pathways of Spread of the Plant Pathogen Phytophthora plurivora.

Author

Schoebel, Corine N., Stewart, Jane, Gruenwald, Niklaus J., Rigling, Daniel, and Prospero, Simone

Subjects
PHYTOPATHOGENIC microorganisms, PHYTOPHTHORA, MICROSATELLITE repeats in plants, PLANT diseases, BIOLOGICAL evolution, POPULATION genetics, POPULATION biology
Abstract

Human activity has been shown to considerably affect the spread of dangerous pests and pathogens worldwide. Therefore, strict regulations of international trade exist for particularly harmful pathogenic organisms. Phytophthora plurivora, which is not subject to regulations, is a plant pathogen frequently found on a broad range of host species, both in natural and artificial environments. It is supposed to be native to Europe while resident populations are also present in the US. We characterized a hierarchical sample of isolates from Europe and the US and conducted coalescent-, migration, and population genetic analysis of sequence and microsatellite data, to determine the pathways of spread and the demographic history of this pathogen. We found P. plurivora populations to be moderately diverse but not geographically structured. High levels of gene flow were observed within Europe and unidirectional from Europe to the US. Coalescent analyses revealed a signal of a recent expansion of the global P. plurivora population. Our study shows that P. plurivora has most likely been spread around the world by nursery trade of diseased plant material. In particular, P. plurivora was introduced into the US from Europe. International trade has allowed the pathogen to colonize new environments and/or hosts, resulting in population growth. [ABSTRACT FROM AUTHOR]

Published
2014
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16. Population History and Pathways of Spread of the Plant Pathogen Phytophthora plurivora.

Author

Schoebel, Corine N., Stewart, Jane, Gruenwald, Niklaus J., Rigling, Daniel, and Prospero, Simone

Subjects
*PHYTOPATHOGENIC microorganisms, *PHYTOPHTHORA, *MICROSATELLITE repeats in plants, *PLANT diseases, *BIOLOGICAL evolution, *POPULATION genetics, *POPULATION biology
Abstract

Human activity has been shown to considerably affect the spread of dangerous pests and pathogens worldwide. Therefore, strict regulations of international trade exist for particularly harmful pathogenic organisms. Phytophthora plurivora, which is not subject to regulations, is a plant pathogen frequently found on a broad range of host species, both in natural and artificial environments. It is supposed to be native to Europe while resident populations are also present in the US. We characterized a hierarchical sample of isolates from Europe and the US and conducted coalescent-, migration, and population genetic analysis of sequence and microsatellite data, to determine the pathways of spread and the demographic history of this pathogen. We found P. plurivora populations to be moderately diverse but not geographically structured. High levels of gene flow were observed within Europe and unidirectional from Europe to the US. Coalescent analyses revealed a signal of a recent expansion of the global P. plurivora population. Our study shows that P. plurivora has most likely been spread around the world by nursery trade of diseased plant material. In particular, P. plurivora was introduced into the US from Europe. International trade has allowed the pathogen to colonize new environments and/or hosts, resulting in population growth. [ABSTRACT FROM AUTHOR]

Published
2014
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