Infection by a foliar endophyte elicits novel arabidopside-based plant defence reactions in its host, Cirsium arvense

Endophytic fungi live asymptomatically within plants. They are usually regarded as non-pathogenic or even mutualistic, but whether plants respond antagonistically to their presence remains unclear, particularly in the little-studied associations between endophytes and nong-raminoid herbaceous plants. We investigated the effects of the endophyte Chaetomium cochlioides on leaf chemistry in Cirsium arvense. Plants were sprayed with spores; leaf material from both subsequent new growth and the sprayed leaves was analysed 2 wk later. Infection frequency was 91% and63% for sprayed and new growth, respectively, indicating that C. cochlioides rapidly infects new foliage. Metabolomic analyses revealed marked changes in leaf chemistry with infection, especially in new growth. Changes in several novel oxylipin metabolites were detected, including arabi-dopsides reported here for the first time in a plant species other than Arabidopsis thaliana,and a jasmonate-containing galactolipid. The production of these metabolites in response to endophyte presence, particularly in newly infected foliage, suggests that endophytes elicit similar chemical responses in plants to those usually produced following wounding, herbivory and pathogen invasion. Whether en-dophytes benefit their hosts may depend on a complex series of chemically mediated interactions between the plant, the endophyte, other microbial colonists and natural enemies

The harlequin ladybird, Harmonia axyridis: global perspectives on invasion history and ecology

The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is native to Asia but has been intentionally introduced to many countries as a biological control agent of pest insects. In numerous countries, however, it has been introduced unintentionally. The dramatic spread of H. axyridis within many countries has been met with considerable trepidation. It is a generalist top predator, able to thrive in many habitats and across wide climatic conditions. It poses a threat to biodiversity, particularly aphidophagous insects, through competition and predation, and in many countries adverse effects have been reported on other species, particularly coccinellids. However, the patterns are not consistent around the world and seem to be affected by many factors including landscape and climate. Research on H. axyridis has provided detailed insights into invasion biology from broad patterns and processes to approaches in surveillance and monitoring. An impressive number of studies on this alien species have provided mechanistic evidence alongside models explaining large-scale patterns and processes. The involvement of citizens in monitoring this species in a number of countries around the world is inspiring and has provided data on scales that would be otherwise unachievable. Harmonia axyridis has successfully been used as a model invasive alien species and has been the inspiration for global collaborations at various scales. There is considerable scope to expand the research and associated collaborations, particularly to increase the breadth of parallel studies conducted in the native and invaded regions. Indeed a qualitative comparison of biological traits across the native and invaded range suggests that there are differences which ultimately could influence the population dynamics of this invader. Here we provide an overview of the invasion history and ecology of H. axyridis globally with consideration of future research perspectives. We reflect broadly on the contributions of such research to our understanding of invasion biology while also informing policy and people.  Additional co-authors: Artur Gil, Audrey A. Grez, Thomas Guillemaud, Danny Haelewaters, Annette Herz, Alois Honek, Andy G. Howe, Cang Hui, William D. Hutchison, Marc Kenis, Robert L. Koch, Jan Kulfan, Lori Lawson Handley, Eric Lombaert, Antoon Loomans, John Losey, Alexander O. Lukashuk, Dirk Maes, Alexandra Magro, Gilles San Martin, Zdenka Martinkova, Ingrid A. Minnaar, Oldřich Nedved, Marina J. Orlova-Bienkowskaja, Naoya Osawa, Wolfgang Rabitsch, Hans Peter Ravn, Gabriele Rondoni, Steph L. Rorke, Sergey K. Ryndevich, May-Guri Saethre, John J. Sloggett, Antonio Onofre Soares, Riaan Stals, Axel Vandereycken, Paul van Wielink, Sandra Viglášová, Peter Zach, Ilya A. Zakharov, Tania Zaviezo, Zihua Zha

Forewarned is forearmed : harmonized approaches for early detection of potentially invasive pests and pathogens in sentinel plantings

This work was supported by COST Action Global Warning (FP1401). DLM and YB contribution was also supported by the Russian Foundation for Basic Research (Grant No. 17-04-01486). MG was supported by Ministry of Education, Science and Technological Development of the Republic of Serbia, Grant III43002. MKA was supported by the Ministry of Science and Higher Education of the Republic of Poland. NK was supported by Le Studium foundation (France) and RFBR (Grant No. 19-04-01029). RE, IF and MK contribution was also supported by CABI with core financial support from its member countries (see http://www.cabi.org/about-cabi/who-we-work-with/key-donors/ for details). IF contribution was further supported through a grant from the Swiss State Secretariat for Science, Education and Research (Grant C15.0081, awarded to RE).Peer reviewedPublisher PD

The harlequin ladybird, Harmonia axyridis: global perspectives on invasion history and ecology

The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is native to Asia but has been intentionally introduced to many countries as a biological control agent of pest insects. In numerous countries, however, it has been introduced unintentionally. The dramatic spread of H. axyridis within many countries has been met with considerable trepidation. It is a generalist top predator, able to thrive in many habitats and across wide climatic conditions. It poses a threat to biodiversity, particularly aphidophagous insects, through competition and predation, and in many countries adverse effects have been reported on other species, particularly coccinellids. However, the patterns are not consistent around the world and seem to be affected by many factors including landscape and climate. Research on H. axyridis has provided detailed insights into invasion biology from broad patterns and processes to approaches in surveillance and monitoring. An impressive number of studies on this alien species have provided mechanistic evidence alongside models explaining large-scale patterns and processes. The involvement of citizens in monitoring this species in a number of countries around the world is inspiring and has provided data on scales that would be otherwise unachievable. Harmonia axyridis has successfully been used as a model invasive alien species and has been the inspiration for global collaborations at various scales. There is considerable scope to expand the research and associated collaborations, particularly to increase the breadth of parallel studies conducted in the native and invaded regions. Indeed a qualitative comparison of biological traits across the native and invaded range suggests that there are differences which ultimately could influence the population dynamics of this invader. Here we provide an overview of the invasion history and ecology of H. axyridis globally with consideration of future research perspectives. We reflect broadly on the contributions of such research to our understanding of invasion biology while also informing policy and people

Field guide for the identification of damage on woody sentinel plants

International audienceAbstract This guide is intended as an aid for managers of sentinel plantings, botanical gardens or arboreta, as well as phytosanitary inspectors, who may have knowledge of common pests and diseases of woody plants, but may not know the likely cause of damage that they have not encountered before. It aims to provide a tentative identification of relatively broad groups of organisms and not definitive identification of the causal agents. Hence, the pictures in this guide need to be regarded as typical examples of the described symptoms. There are chapters that explain how to use the guide, followed by keys (for different organs of conifer and broadleaf species) to guide the user to the relevant sections of the book, based on the questions entomologists and pathologists ask themselves when looking at a damaged or diseased tree in a fashion similar to how a doctor interrogates a patient to arrive at a diagnosis. The largest part of the book is devoted to the description and illustration of damage types and typical causes of the observed damage. The last chapters provide instructions for taking and preserving samples for further identification by an expert, notification of relevant authorities, and a glossary

The sentinel tree nursery as an early warning system for pathway risk assessment: Fungal pathogens associated with Chinese woody plants commonly shipped to Europe

<div><p>Introduction of and invasion by alien plant pathogens represents the main cause of emerging infectious diseases affecting domesticated and wild plant species worldwide. The trade in living plants is the most common pathway of introduction. Many of the alien tree pathogens recently introduced into Europe were not previously included on any quarantine lists. To help determine the potential risk of pest introduction through trading of ornamental plants, a sentinel nursery was established in Beijing, China in 2008. The sentinel nursery planting included four of the most common ornamental woody species shipped to Europe including <i>Ilex cornuta</i> var. <i>fortunae</i>, <i>Zelkova schneideriana</i>, <i>Fraxinus chinensis</i> and <i>Buxus microphylla</i>. Symptoms developing on these species within the sentinel nursery were detected in 2013 and consisted of necrotic spots on leaves, canker and stem necrosis, shoot blight and shoot necrosis. Fungi associated with the trees and their symptoms included <i>Alternaria alternata</i> detected from all hosts; <i>Diaporthe liquidambaris</i> and <i>Diaporthe capsici</i> from bark and leaf necrosis of <i>Zelkova schneideriana</i>; <i>Botryosphaeria dothidea</i> and <i>Nothophoma quercina</i> from stem cankers on <i>Fraxinus chinensis</i> and leaf necrosis on <i>Ilex cornuta</i>; and <i>Pseudonectria foliicola</i> from leaf necrosis on <i>Buxus microphylla</i>. Next generation sequencing analysis from asymptomatic tissues detected eighteen OTU’s at species level among which some taxa had not been previously recorded in Europe. These results clearly demonstrate that looking at trees of internationally traded species in the region of origin can reveal the presence of potentially harmful organisms of major forestry, landscape or crop trees. Results of this study also provide an indication as to how some disease agents can be introduced using pathways other than the co-generic hosts. Hence, sentinel nurseries represent one potential mechanism to address the current lack of knowledge about pests in the countries from where live plants are shipped and the threats they represent to native flora and crops in importing countries.</p></div

Infection by a foliar endophyte elicits novel arabidopside-based plant defence reactions in its host, Cirsium arvense

Endophytic fungi live asymptomatically within plants. They are usually regarded as non-pathogenic or even mutualistic, but whether plants respond antagonistically to their presence remains unclear, particularly in the little-studied associations between endophytes and nong-raminoid herbaceous plants. We investigated the effects of the endophyte Chaetomium cochlioides on leaf chemistry in Cirsium arvense. Plants were sprayed with spores; leaf material from both subsequent new growth and the sprayed leaves was analysed 2 wk later. Infection frequency was 91% and63% for sprayed and new growth, respectively, indicating that C. cochlioides rapidly infects new foliage. Metabolomic analyses revealed marked changes in leaf chemistry with infection, especially in new growth. Changes in several novel oxylipin metabolites were detected, including arabi-dopsides reported here for the first time in a plant species other than Arabidopsis thaliana,and a jasmonate-containing galactolipid. The production of these metabolites in response to endophyte presence, particularly in newly infected foliage, suggests that endophytes elicit similar chemical responses in plants to those usually produced following wounding, herbivory and pathogen invasion. Whether en-dophytes benefit their hosts may depend on a complex series of chemically mediated interactions between the plant, the endophyte, other microbial colonists and natural enemies

Neighbour-joining trees of the OTU82 (from NGS analysis), the ITS sequence of isolate of <i>Pseudonectria foliicola</i> from this study, and top BLAST hits species (with GenBank accession numbers).

<p>Numbers above branches represent bootstrap support for the nodes and posterior probability based on Bayesian analysis of the dataset (in bold). ^<i>¥</i> Sequence with 100% of identity with <i>P</i>. <i>foliicola</i>.</p

Symptoms on sentinel nursery trees.

<p>Leaf necrosis on <i>Buxus microphylla</i> (a); canker on <i>Fraxinus chinensis</i> (b); leaf necrosis on <i>Ilex cornuta</i> var. <i>fortunei</i> (c); and bark necrosis on <i>Zelkova schneideriana</i> (d).</p

Heatmap of the abundance of the fungal taxa identified as species by NGS analysis from sentinel nursery plants.

<p>Higher intensities of the colour reveal higher abundances of the isolates. <i>Zelkova schneideriana</i> (ZS); <i>Ilex cornuta</i> var. <i>fortunei</i> (IC); <i>Buxus microphylla</i> (BM); <i>Fraxinus chinensis</i> (FC).* Ambiguous species identification, possible new species.</p