DOCSLIB.ORG

Alnus Glutinosa Threatened by Alder Phytophthora: a Histological Study of Roots

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Alnus Glutinosa Threatened by Alder Phytophthora: a Histological Study of Roots pathogens Article Alnus glutinosa Threatened by Alder Phytophthora: A Histological Study of Roots Corina Nave 1 , Juliette Schwan 2, Sabine Werres 1 and Janett Riebesehl 1,* 1 Julius Kühn Institute (JKI)–Federal Research Centre for Cultivated Plants, Institute for Plant Protection in Horticulture and Forests, Messeweg 11/12, 38104 Braunschweig, Germany; [email protected] (C.N.); [email protected] (S.W.) 2 Julius Kühn Institute (JKI)–Federal Research Centre for Cultivated Plants, Institute for National and International Plant Health, Messeweg 11/12, 38104 Braunschweig, Germany; [email protected] * Correspondence: [email protected] Abstract: Alder dieback remains a major problem in European alder stands and its spread continues to threaten their existence. The causal agent of this disease is the so-called alder Phytophthora species complex, which includes the hybrid Phytophthora ×alni and its parental species P. uniformis and P. ×multiformis. Little is known about the survival of these Phytophthora species in alder. The aim of our investigations was to find out whether, and if so where, the pathogen survives. The subject of these studies was alder roots. Therefore, artificial infection studies and histological studies with P. ×alni and P. uniformis were carried out on seedlings of black alder (Alnus glutinosa). These histological studies revealed oogonia and oospores of P. ×alni and P. uniformis in different parts of the root tissue. Keywords: clade 7; plant pathology; thin sections Citation: Nave, C.; Schwan, J.; Werres, S.; Riebesehl, J. Alnus Glutinosa Threatened by Alder 1. Introduction Phytophthora: A Histological Study of Common alder, also known as black alder (Alnus glutinosa ([L.] GAERTN.), is a very Roots. Pathogens 2021, 10, 977. common tree species in Europe. Its occurrence ranges from the Mediterranean in the south https://doi.org/10.3390/ and Ireland in the west to mid-Scandinavia in the north and western Siberia in the east. It is pathogens10080977 adapted to moderate to cold climates and prefers to grow in stands tied to water [1]. In this context, it plays a key role in the bank stabilization of water bodies. It also benefits aquatic Academic Editor: Paolo Gonthier ecosystems in numerous ways, including its ability to fixate nitrogen and its importance to various species as a source of food and shelter [2]. Black alders are almost unique in their Received: 17 June 2021 role and cannot be easily replaced by any other tree species [3–7]. Accepted: 28 July 2021 Since the early 1990s, dieback in the genus Alder has been observed throughout Published: 3 August 2021 Europe. The first record of this issue was in the United Kingdom in 1993, followed by other European countries before it was detected in Germany in 1998—e.g., [8–11]. The disease Publisher’s Note: MDPI stays neutral primarily occurs near flowing waters. Affected alders show dead bark areas and mucilage with regard to jurisdictional claims in flow at the base of the trunk due to cambium necrosis, as well as severe crown thinning published maps and institutional affil- before death. In this process, the alders often die within about three years of infection [12]. iations. The disease is caused by the Phytophthora alni species complex, which consists of P. ×alni (Brasier and S. A. Kirk) Husson, Ioos and Marçais, nothosp. nov.; P. uniformis (Brasier and S. A. Kirk) Husson, Ioos and Aguayo, comb. nov.; and P. ×multiformis (Brasier and S. A. Kirk) Husson, Ioos and Frey, nothosp. nov. [13,14]. P. ×alni is the result of Copyright: © 2021 by the authors. a hybridization event between P. uniformis and P. ×multiformis [14–16] and is the most Licensee MDPI, Basel, Switzerland. aggressive of the three oomycetes [17]. The alder Phytophthora is extensively distributed in This article is an open access article Central Europe [5]. These alders belong to clade 7 in DNA-based phylogenies, according distributed under the terms and to the key of Waterhouse [18], and are root pathogens, like most representatives in this conditions of the Creative Commons group [19]. Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ These are host-specific pathogens on alder trees, that, like all Phytophthora species, are 4.0/). perfectly adapted to water. Their zoospores are considered the main dispersal organs, and Pathogens 2021, 10, 977. https://doi.org/10.3390/pathogens10080977 https://www.mdpi.com/journal/pathogens Pathogens 2021, 10, x FOR PEER REVIEW 2 of 12 Pathogens 2021, 10, 977 2 of 11 These are host-specific pathogens on alder trees, that, like all Phytophthora species, theyare perfectly are able toadapted actively to swimwater. toTheir host zoospores plants with are theconsidered help of the their main two dispersal flagella [organs,20]. They areand also they able are to able form to actively oospores swim [12]. to With host these plants resting with the spores, help of the their pathogens two flagella can survive[20]. forThey years are even also withoutable to form a host oospores plant—e.g., [12]. inWith the these soil [ 21resting]. spores, the pathogens can survive for years even without a host plant—e.g., in the soil [21]. There has been no previous evidence of oospores in the roots of alder trees, let alone There has been no previous evidence of oospores in the roots of alder trees, let alone the presence of the pathogen in this tissue in general. Therefore, inoculation experiments the presence of the pathogen in this tissue in general. Therefore, inoculation experiments with P. ×alni and P. uniformis were carried out on black alder seedlings and the roots were with P. ×alni and P. uniformis were carried out on black alder seedlings and the roots were subsequently examined histologically. The purpose of this study was to investigate whether subsequently examined histologically. The purpose of this study was to investigate the pathogens are present in the roots after inoculation, which tissues they colonize, and whether the pathogens are present in the roots after inoculation, which tissues they colo- whether they are able to form resting spores. The results show that both species are capable nize, and whether they are able to form resting spores. The results show that both species ofare penetrating capable of thepenetrating roots; spreading the roots; inspreading the tissue; in the and tissue; forming and oogonia,forming oogonia, oospores, oo- and sporangia.spores, and sporangia. 2. Results 2. Results At the end of the inoculation studies, several root samples were taken per category (0 At the end of the inoculation studies, several root samples were taken per category to(0 4) to and 4) and examined examined histologically. histologically. The The results results for for the the health health status status andand levellevel of damage of theof plantsthe plants are are not not presented presented here. here. 2.1. Non-Inoculated Alders (Negative Controls) 2.1. Non-Inoculated Alders (Negative Controls) The roots of the non-inoculated plants showed healthy tissue with normally developed The roots of the non-inoculated plants showed healthy tissue with normally devel- cells.oped No cells. foreign No foreign structures, structures, such assuch mycelium as mycelium or spores or spores of oomycetous of oomycetous or fungal or fungal origin, couldorigin, be could found. be The found. cells The were cells stained were middlestained middle to light to blue, light except blue, forexcept the epidermis.for the epider- These cellsmis. showed These cells a brown showed to yellowa brown coloration to yellow coloration (Figure1). (Figure 1). FigureFigure 1. Thin1. Thin sections sections of of non-inoculated non-inoculated roots roots fromfrom AlnusAlnus glutinosa.. Epidermis Epidermis (e), (e), cortex cortex (c), (c), and and vascular vascular cylinder cylinder (vc). (vc). (A),(A longitudinal), longitudinal section. section. (B (),B), cross-section. cross-section. 2.2.2.2. Alders Alders Inoculatedinoculated with Phytophthora ×alni×alni TheThe roots roots from from the the plants plants of of category category 0 (Figure0 (Figure2A–C)—i.e., 2A–C)—i.e., plants plants without without symptoms— symp- weretoms—were found to found have someto have cells some of thecells vascular of the va cylinderscular cylinder (vc) stained (vc) stained blue to blue green toor green brown (Figureor brown2A). (Figure In the peripheral2A). In the peripheral area of the area cortex, of the an cortex, oogonium an oogonium with an oospore with an insideoospore was detectedinside was intracellularly. detected intracellularly. Mycelium was Mycelium also seen was adjacently also seen (Figureadjacently2A). (Figure The cross-section 2A). The ofcross-section another sample of another showed sample an oogonium showed an intercellularly. oogonium intercellularly. All cells showed All cells a middle showed to darka bluemiddle coloration to dark (Figureblue coloration2B). Figure (Figure2C shows 2B). Fi agure part 2C of shows the roots a part where of the the roots cutting where process the damagedcutting process the cells. damaged Nevertheless, the cells. Neverthele oogonia (stainedss, oogonia blue) (stained and hyphalblue) and swelling hyphal swell- (stained yellow)ing (stained are visible yellow) within are visible the cells within (Figure the cells2C). (Figure 2C). 2 Pathogens 2021, 10, 977 3 of 11 Pathogens 2021, 10, x FOR PEER REVIEW 4 of 12 Figure 2. Thin sections of roots from Alnus glutinosa inoculated with Phytophthora ×alni three weeks after inoculation. (A) Figure 2. Alnus glutinosa Phytophthora ×alni Thinplant sections health status of rootscategory from (phsc) 0, longitudinal section,inoculated intracellular with oogonium with oospore in thethree cortex weeks (black arrow). after inoculation. (A) plant health(B) Phsc status 0, cross category-section, intercellular (phsc) 0, longitudinaloogonium (black section, arrow). ( intracellularC) Phsc 0, longitudinal oogonium section, with several oospore intracellular in theoogo- cortex (black arrow). (B) Phscnia (black 0, cross-section, arrows), and hyphal intercellular swellings oogonium (red arrows).
Load more

Recommended publications
  • Alnus Glutinosa
    bioRxiv preprint doi: https://doi.org/10.1101/2019.12.13.875229; this version posted December 13, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. Investigations into the declining health of alder (Alnus glutinosa) along the river Lagan in Belfast, including the first report of Phytophthora lacustris causing disease of Alnus in Northern Ireland Richard O Hanlon (1, 2)* Julia Wilson (2), Deborah Cox (1) (1) Agri-Food and Biosciences Institute, Belfast, BT9 5PX, Northern Ireland, UK. (2) Queen’s University Belfast, Northern Ireland, UK * [email protected] Additional key words: Plant health, Forest pathology, riparian, root and collar rot. Abstract Common alder (Alnus glutinosa) is an important tree species, especially in riparian and wet habitats. Alder is very common across Ireland and Northern Ireland, and provides a wide range of ecosystem services. Surveys along the river Lagan in Belfast, Northern Ireland led to the detection of several diseased Alnus trees. As it is known that Alnus suffers from a Phytophthora induced decline, this research set out to identify the presence and scale of the risk to Alnus health from Phytophthora and other closely related oomycetes. Sampling and a combination of morphological and molecular testing of symptomatic plant material and river baits identified the presence of several Phytophthora species, including Phytophthora lacustris. A survey of the tree vegetation along an 8.5 km stretch of the river revealed that of the 166 Alnus trees counted, 28 were severely defoliated/diseased and 9 were dead.
    [Show full text]
  • Presidio Phytophthora Management Recommendations
    2016 Presidio Phytophthora Management Recommendations Laura Sims Presidio Phytophthora Management Recommendations (modified) Author: Laura Sims Other Contributing Authors: Christa Conforti, Tom Gordon, Nina Larssen, and Meghan Steinharter Photograph Credits: Laura Sims, Janet Klein, Richard Cobb, Everett Hansen, Thomas Jung, Thomas Cech, and Amelie Rak Editors and Additional Contributors: Christa Conforti, Alison Forrestel, Alisa Shor, Lew Stringer, Sharon Farrell, Teri Thomas, John Doyle, and Kara Mirmelstein Acknowledgements: Thanks first to Matteo Garbelotto and the University of California, Berkeley Forest Pathology and Mycology Lab for providing a ‘forest pathology home’. Many thanks to the members of the Phytophthora huddle group for useful suggestions and feedback. Many thanks to the members of the Working Group for Phytophthoras in Native Habitats for insight into the issues of Phytophthora. Many thanks to Jennifer Parke, Ted Swiecki, Kathy Kosta, Cheryl Blomquist, Susan Frankel, and M. Garbelotto for guidance. I would like to acknowledge the BMP documents on Phytophthora that proceeded this one: the Nursery Industry Best Management Practices for Phytophthora ramorum to prevent the introduction or establishment in California nursery operations, and The Safe Procurement and Production Manual. 1 Title Page: Authors and Acknowledgements Table of Contents Page Title Page 1 Table of Contents 2 Executive Summary 5 Introduction to the Phytophthora Issue 7 Phytophthora Issues Around the World 7 Phytophthora Issues in California 11 Phytophthora
    [Show full text]
  • Distribution and Severity of Alder Phytophthora in Alaska1
    Proceedings of the Sudden Oak Death Fourth Science Symposium Distribution and Severity of Alder 1 Phytophthora in Alaska G.C. Adams,2 M. Catal,2 and L. Trummer3 Abstract In Alaska, an unprecedented dieback and mortality of Alnus incana ssp. tenuifolia has occurred which stimulated an effort to determine causal agents of the disease. In Europe, similar dieback and mortality of Alnus incana and Alnus glutinosa has been attributed to root rot by a spectrum of newly emergent strains in the hybrid species Phytophthora alni. The variable hybrids of P. alni were grouped into three subspecies: P. alni ssp. alni (PAA), P. alni ssp. multiformis (PAM), and P. alni ssp. uniformis (PAU). From 2007 to 2008, we conducted a survey of Phytophthora species at 30 locations with stream baiting as used in the 2007 national Phytophthora ramorum Early Detection Survey for Forests in the United States. Additionally, Phytophthora species from saturated rhizosphere soil beneath alder stands were baited in situ using rhododendron leaves. We discovered PAU in rhizosphere soils in 2007 at two sample locations in unmanaged stands hundreds of miles apart, on the Kenai Peninsula and near Denali National Park. PAA was reported to be the most aggressive and pathogenic to alders and PAM and PAU were significantly less aggressive than PAA, though still pathogenic. To ascertain whether PAU was of restricted distribution due to recent introduction, or widespread distribution, we extended the survey in 2008 to 81 locations. Intensive sampling was conducted at five alder stands exhibiting dieback and 10 alder genets per location were excavated to expose nearly the entire root system for evaluation of the severity of root rot, ELISA detection of Phytophthora in diseased roots, and isolation of Phytophthora species.
    [Show full text]
  • Alder Canopy Dieback and Damage in Western Oregon Riparian Ecosystems
    Alder Canopy Dieback and Damage in Western Oregon Riparian Ecosystems Sims, L., Goheen, E., Kanaskie, A., & Hansen, E. (2015). Alder canopy dieback and damage in western Oregon riparian ecosystems. Northwest Science, 89(1), 34-46. doi:10.3955/046.089.0103 10.3955/046.089.0103 Northwest Scientific Association Version of Record http://cdss.library.oregonstate.edu/sa-termsofuse Laura Sims,1, 2 Department of Botany and Plant Pathology, Oregon State University, 1085 Cordley Hall, Corvallis, Oregon 97331 Ellen Goheen, USDA Forest Service, J. Herbert Stone Nursery, Central Point, Oregon 97502 Alan Kanaskie, Oregon Department of Forestry, 2600 State Street, Salem, Oregon 97310 and Everett Hansen, Department of Botany and Plant Pathology, 1085 Cordley Hall, Oregon State University, Corvallis, Oregon 97331 Alder Canopy Dieback and Damage in Western Oregon Riparian Ecosystems Abstract We gathered baseline data to assess alder tree damage in western Oregon riparian ecosystems. We sought to determine if Phytophthora-type cankers found in Europe or the pathogen Phytophthora alni subsp. alni, which represent a major threat to alder forests in the Pacific Northwest, were present in the study area. Damage was evaluated in 88 transects; information was recorded on damage type (pathogen, insect or wound) and damage location. We evaluated 1445 red alder (Alnus rubra), 682 white alder (Alnus rhombifolia) and 181 thinleaf alder (Alnus incana spp. tenuifolia) trees. We tested the correlation between canopy dieback and canker symptoms because canopy dieback is an important symptom of Phytophthora disease of alder in Europe. We calculated the odds that alder canopy dieback was associated with Phytophthora-type cankers or other biotic cankers.
    [Show full text]
  • Analyses of Hybrid Viability Across a Hybrid Zone Between Two Alnus Species Using Microsatellites and Cpdna Markers
    G C A T T A C G G C A T genes Article Analyses of Hybrid Viability across a Hybrid Zone between Two Alnus Species Using Microsatellites and cpDNA Markers Jan Šmíd 1, Jan Douda 1, Karol Krak 1,2 and Bohumil Mandák 1,2,* 1 Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic; [email protected] (J.Š.); [email protected] (J.D.); [email protected] (K.K.) 2 Institute of Botany, Czech Academy of Sciences, Zámek 1, CZ-252 43 Pr ˚uhonice,Czech Republic * Correspondence: [email protected] Received: 18 June 2020; Accepted: 6 July 2020; Published: 9 July 2020 Abstract: Diploid Alnus glutinosa s. str. and autotetraploid A. rohlenae form a narrow hybrid zone in a study area in southern Serbia, which results in triploid hybrid formation. The vast majority of previous studies have been focused on studies of maternal plants, but the offspring resulting from their crossing have not been much studied. Here, we use the variability of microsatellites and chloroplast DNA between these species and their putative hybrids to create an overall picture of the development of the hybrid zone and its predicted type. To elucidate the gene transfer within both species, the origins of individual ploidies and especially the role of triploid hybrids, a germination experiment was carried out linked with a flow cytometry study of the resulting seedlings. The tension zone model seems to offer the most adequate explanation of our observations, with selection against triploid hybrids and the spatial positioning of the hybrid zone.
    [Show full text]
  • Phytophthora Alni Globally Using Both Statistical Analyses and Expert Knowledge
    Previous Advances in Threat Assessment and Their Application to Forest and Rangeland Management Estimating the Susceptibility to Phytophthora alni Globally Using Both Statistical Analyses and Expert Knowledge Marla C. Downing, Thomas Jung, Vernon Thomas, Keywords: Alder, Alnus, classification tree, hazard, Markus Blaschke, Michael F. Tuffly, and Robin Reich pathogen, Phytophthora alni, risk. Marla C. Downing, program manager, Invasive Species Introduction Information, USDA Forest Service, Forest Health Protec- Phytophthora alni Brasier and S.A. Kirk is a host-specific, tion, Forest Health Technology Enterprise Team, Fort highly aggressive soil and waterborne pathogen that causes Collins, CO 80526; Thomas Jung, independent scientist root and collar rot of Alnus (alder) spp. All European alder and consultant for tree diseases, pathologist, Brannenburg, species (i.e., black alder [A. glutinosa (L.) Gaertn.], gray Germany; Vernon Thomas, spatial analyst, Information alder [A. incana (L.) Moench], Italian alder [A. cordata Technology Experts, Inc., Fort Collins, CO 80525; Markus (Loisel.) Duby], and green alder [A. viridis] (Chaix) DC.) Blaschke, Bavarian State Institute of Forestry (LWF), Sec- and the North American red alder (A. rubra Bong. ) are tion Forest Ecology and Forest Protection, Freising, Ger- highly susceptible (Jung and Blaschke 2006, Gibbs and many; Michael F. Tuffly, ERIA Consultants, LLC, spatial others 2003). The susceptibility of other North and South analyst, Boulder, CO 80305; and Robin Reich, Department American and Asian alder species is currently unknown. of Forest, Rangeland and Watershed Stewardship, professor, Phytophthora alni was shown to be a recent interspecific Colorado State University, Fort Collins, CO 80525. hybrid between P. cambivora (Petri) Buisman and another species closely related to P.
    [Show full text]
  • Phytophthora Alni on Alnus Glutinosa Reported for the First Time in Spain
    Plant Pathology (2010) 59, 798 Doi: 10.1111/j.1365-3059.2009.02254.x Phytophthora alni on Alnus glutinosa reported for the first time in Spain A. Sollaa,A.Pe´rez-Sierrab, T. Corcobadoa, M. M. Haquec, J. J. Diezc and T. Jungde* aIngenierı´aTe´cnica Forestal, Universidad de Extremadura, Avenida Virgen del Puerto 2, 10600 Plasencia; bInstituto Agroforestal Mediterra´neo, Universidad Polite´cnica de Valencia, Camino de Vera s ⁄ n, 46022 Valencia; cProduccio´n Vegetal y Recursos Forestales, Universidad de Valladolid, Avenida de Madrid 44, 34071 Palencia, Spain; dPhytophthora Research and Consultancy, Thomastrasse 75, 83098 Brannenburg, Germany; and eCentre for Phytophthora Science and Management, School of Biological Sciences and Biotechnology, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia Since the mid 2000s extensive mortality of common alder (Alnus glutin- which will allow the administration to adopt proper management osa) has been observed along many rivers of northern Spain (Tuset et al., strategies. 2006). Symptoms include sparse yellowish and small-sized foliage, die- back of branches, increased fruit production and dark-stained necrosis of the bark at the collar and lower stem. These resemble symptoms of the Acknowledgements root and collar rot epidemic of alders which is caused by the different sub- We thank O. Locos and to P. Abad-Campos. Supported by Consejerı´as species of the host-specific pathogen Phytophthora alni and has led to high ECI and IEMA (Junta de Extremadura, III-PRI 08-A78), University of mortality of riparian alders across 14 countries in Western, Central and Valladolid (061 ⁄ 060831), and Ministerio Educacio´ n y Ciencia Northern Europe (Gibbs et al., 2003; Jung & Blaschke, 2004).
    [Show full text]
  • <I>Phytophthora Alni</I>
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Papers in Plant Pathology Plant Pathology Department 2-2013 Strong Genetic Differentiation Between North American and European Populations of Phytophthora alni subsp. uniformis Jaime Aguayo Université de Lorraine Gerard C. Adams University of Nebraska-Lincoln, [email protected] Fabien Halkett Université de Lorraine Mursel Catal Akdeniz University Claude Husson Université de Lorraine See next page for additional authors Follow this and additional works at: http://digitalcommons.unl.edu/plantpathpapers Part of the Other Plant Sciences Commons, Plant Biology Commons, and the Plant Pathology Commons Aguayo, Jaime; Adams, Gerard C.; Halkett, Fabien; Catal, Mursel; Husson, Claude; Nagy, Zoltán Á.; Hansen, Everett M.; Marçais, Benoît; and Frey, Pascal, "Strong Genetic Differentiation Between North American and European Populations of Phytophthora alni subsp. uniformis" (2013). Papers in Plant Pathology. 286. http://digitalcommons.unl.edu/plantpathpapers/286 This Article is brought to you for free and open access by the Plant Pathology Department at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Papers in Plant Pathology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Jaime Aguayo, Gerard C. Adams, Fabien Halkett, Mursel Catal, Claude Husson, Zoltán Á. Nagy, Everett M. Hansen, Benoît Marçais, and Pascal Frey This article is available at DigitalCommons@University of Nebraska - Lincoln:
    [Show full text]
  • Phytophthora Pathogens Threaten Rare Habitats and Conservation Plantings
    Phytophthora pathogens threaten rare habitats and conservation plantings Susan J. Frankel1, Janice Alexander2, Diana Benner3, Janell Hillman4 & Alisa Shor5 Abstract Phytophthora pathogens are damaging native wildland vegetation including plants in restoration areas and botanic gardens. The infestations threaten some plants already designated as endangered and degrade high-value habitats. Pathogens are being introduced primarily via container plant nursery stock and, once established, they can spread to adjacent areas where plant species not previously exposed to pathogens may become infected. We review epidemics in California – caused by the sudden oak death pathogen Phytophthora ramorum Werres, De Cock & Man in ‘t Veld and the frst USA detections of P. tentaculata Krber & Marwitz, which occurred in native plant nurseries and restoration areas – as examples to illustrate these threats to conservation plantings. Introduction stock) (Liebhold et al., 2012; Parke et al., Phytophthora (order: Peronosporales; 2014; Jung et al., 2015; Swiecki et al., kingdom: Stramenopila) pathogens 2018b; Sims et al., 2019). Once established, have increasingly been identifed as Phytophthora spp. have the potential associated with plant dieback and to reduce growth, kill and cause other mortality in restoration areas (Bourret, undesirable impacts on a wide variety of 2018; Garbelotto et al., 2018; Sims et al., native or horticultural vegetation (Brasier 2019), threatened and endangered species et al., 2004; Hansen 2007, 2011; Scott & habitat (Swiecki et al., 2018a), botanic Williams, 2014; Jung et al., 2018). gardens and wildlands in coastal California In this review, we focus on the (Cobb et al., 2017; Metz et al., 2017) and consequences of two pathogen southern Oregon (Goheen et al., 2017).
    [Show full text]
  • Genetic Diversity and Origins of the Homoploid Type Hybrid Phytophthora ×Alni
    Applied and Environmental Microbiology doi:10.1128/AEM.02221-16. Supplemental data: http://dx.doi.org/10.1128/AEM.02221-16 Received29 July 2016 Accepted22 September 2016 Genetic diversity and origins of the homoploid type hybrid Phytophthora ×alni Jaime Aguayo1*, Fabien Halkett2, Claude Husson2, Zoltán Á. Nagy3, András Szigethy3, József Bakonyi3, Pascal Frey2 and Benoit Marçais2 1 ANSES, Laboratoire de la Santé des Végétaux, Unité de Mycologie, Malzéville, France. 2 UMR IAM, INRA, Université de Lorraine, Nancy, France. 3 Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences. Budapest, Hungary. Running Head: Genetic structure of an homoploid pathogen *Address correspondence to Benoit Marçais, [email protected] P.F. and B.M. co-directed this work Summary Assessing the process that gives rise to hybrid pathogens is central to understand the evolution of emerging plant diseases. Phytophthora ×alni, a pathogen of alder, results from the homoploid hybridization of two related species, Phytophthora uniformis and Phytophthora ×multiformis. Describing genetic characteristics of P. ×alni should help understanding how reproductive mechanisms and historical processes shaped the population structure of this emerging hybrid pathogen. The population genetic structure of P. ×alni and the relationship with its parental species was investigated using twelve microsatellites and one mitochondrial DNA (mtDNA) marker on a European collection of 379 isolates. Populations of P. ×alni were dominated by one multilocus genotype (MLG). The frequency of this dominant MLG increased after the disease emergence together with a decline in diversity, suggesting that it was favoured by a genetic mechanism such as drift or selection. Combined microsatellite and mtDNA results confirmed that P.
    [Show full text]
  • Minnesota's Top 124 Terrestrial Invasive Plants and Pests
    Photo by RichardhdWebbWebb 0LQQHVRWD V7RS 7HUUHVWULDO,QYDVLYH 3ODQWVDQG3HVWV 3ULRULWLHVIRU5HVHDUFK Sciencebased solutions to protect Minnesota’s prairies, forests, wetlands, and agricultural resources Contents I. Introduction .................................................................................................................................. 1 II. Prioritization Panel members ....................................................................................................... 4 III. Seventeen criteria, and their relative importance, to assess the threat a terrestrial invasive species poses to Minnesota ...................................................................................................................... 5 IV. Prioritized list of terrestrial invasive insects ................................................................................. 6 V. Prioritized list of terrestrial invasive plant pathogens .................................................................. 7 VI. Prioritized list of plants (weeds) ................................................................................................... 8 VII. Terrestrial invasive insects (alphabetically by common name): criteria ratings to determine threat to Minnesota. .................................................................................................................................... 9 VIII. Terrestrial invasive pathogens (alphabetically by disease among bacteria, fungi, nematodes, oomycetes, parasitic plants, and viruses): criteria ratings
    [Show full text]
  • EPPO Reporting Service
    ORGANISATION EUROPEENNE EUROPEAN AND MEDITERRANEAN ET MEDITERRANEENNE PLANT PROTECTION POUR LA PROTECTION DES PLANTES ORGANIZATION EPPO Reporting Service NO. 4 PARIS, 2007-04-01 CONTENTS _____________________________________________________________________ Pests & Diseases 2007/066 - EPPO Plant Protection Thesaurus (EPPT) is available from the EPPO website 2007/067 - First report of Agrilus planipennis in the region of Moscow, Russia 2007/068 - Tetrastichus planipennisi is a parasitoid of Agrilus planipennis in China 2007/069 - New arthropods identified in Israel 2007/070 - Oak mortality in Japan is caused by Raffaelea quercivora and its insect vector Platypus quercivorus 2007/071 - Phytophthora alni identified in the Czech Republic 2007/072 - First report of Cryphonectria parasitica in Azerbaijan 2007/073 - First report of Plasmopara obducens in Australia 2007/074 -‘Candidatus Phytoplasma mali’ identified in Prunus avium, P. armeniaca and P. domestica 2007/075 -‘Candidatus Phytoplasma palmae’ detected in Cedusa sp. (Homoptera: Derbidae) in Jamaica 2007/076 - Recent studies on the phytoplasmas associated with the Al-Wijam disease of date palm 2007/077 - First report of Tomato chlorosis virus in Mexico 2007/078 - First report of Tomato yellow leaf curl virus in Tunisia 2007/079 - Genetic studies of Pepino mosaic virus in Spain 2007/080 - New data on quarantine pests and pests of the EPPO Alert List CONTENTS _______________________________________________________________________Invasive Plants 2007/081 - Voluntary codes of conduct in the USA 2007/082 - Horticultural codes of practice in the United Kingdom 2007/083 - Participation of the nursery industry in controlling invasive alien plants: a booklet of substitute plants for southern France 2007/084 - Participation of the nursery industry in controlling invasive alien plants in France: a charter with retailers 2007/085 - New records of aquatic plants in Germany 1, rue Le Nôtre Tel.
    [Show full text]