{"id":8392,"date":"2017-11-10T08:21:55","date_gmt":"2017-11-10T08:21:55","guid":{"rendered":"https:\/\/mycor.iam.inrae.fr\/IAM\/?p=8392"},"modified":"2017-11-10T22:12:41","modified_gmt":"2017-11-10T22:12:41","slug":"thesis-m-grosdidier","status":"publish","type":"post","link":"https:\/\/mycor.iam.inrae.fr\/IAM\/?p=8392","title":{"rendered":"PhD: Marie Grosdidier"},"content":{"rendered":"

Madame Marie GROSDIDIER<\/p>\n

A brillamment soutenu\u00a0ses travaux de th\u00e8se intitul\u00e9s<\/p>\n

Epid\u00e9miologie de la Chalarose du fr\u00eane, une maladie caus\u00e9e par l\u2019agent pathog\u00e8ne <\/em>Hymenoscyphus fraxineus<\/p>\n

Le vendredi 10 novembre 2017 \u00e0 9h30
\nLieu : \u00a0Amphi 7, Campus Aiguillettes, 54506 Vand\u0153uvre-l\u00e8s-Nancy<\/p>\n

\"IMG_3798\"<\/a><\/p>\n

\"IMG_3800\"<\/a><\/p>\n

Composition du jury (de gauche \u00e0 droite sur la photo) :<\/p>\n

M. Valentin Queloz, WSL, Birmensdorf, Suisse, Examinateur<\/p>\n

M. Pascal Hendrikx, Anses, Lyon, Examinateur<\/p>\n

M. Renaud Ioos, Anses, Nancy, Co-directeur de th\u00e8se<\/p>\n

(Mme Marie Grosdidier)<\/p>\n

Mme C\u00e9cile Robin, Inra Bordeaux, Rapporteure<\/p>\n

M. Benoit Mar\u00e7ais, Inra Nancy, Directeur de th\u00e8se<\/p>\n

M. Ivan Sache, AgroParisTech, Paris, Rapporteur<\/p>\n

Mme M\u00e9lanie Morel, Universit\u00e9 de Lorraine, Pr\u00e9sidente du jury<\/p>\n

 <\/p>\n

 <\/p>\n\n\n\n\n
R\u00e9sum\u00e9\u00a0:<\/strong><\/td>\n<\/tr>\n
L\u2019introduction de champignons pathog\u00e8nes envahissants est une cause tr\u00e8s importante d\u2019\u00e9mergence de maladies foresti\u00e8res. Depuis ces 30 derni\u00e8res ann\u00e9es, la Chalarose affecte s\u00e9v\u00e8rement les fr\u00eanes en particulier Fraxinus excelsior<\/em>. L\u2019agent pathog\u00e8ne causant cette maladie est un ascomyc\u00e8te originaire d\u2019Asie de l\u2019Est, Hymenoscyphus<\/em> fraxineus<\/em>. Il fut observ\u00e9 pour la premi\u00e8re fois dans les ann\u00e9es 1990 en Pologne, puis s\u2019est rapidement diss\u00e9min\u00e9 en Europe pour atteindre la France en 2008. La maladie se diss\u00e9mine principalement par dispersion a\u00e9rienne des ascospores. Cette th\u00e8se vise \u00e0 \u00e9tudier l\u2019\u00e9pid\u00e9miologie de la Chalarose du fr\u00eane en d\u00e9terminant les facteurs environnementaux influen\u00e7ant le d\u00e9veloppement d\u2019H<\/em>. fraxineus<\/em> et en proposant un mod\u00e8le de dispersion de la maladie. Le premier objectif de cette th\u00e8se visait \u00e0 optimiser une m\u00e9thode de pi\u00e9geage de l\u2019inoculum a\u00e9rien pour ensuite l\u2019utiliser dans le but d\u2019\u00e9tudier le patron de dispersion d\u2019H<\/em>. fraxineus<\/em>. Nous avons ainsi mis en place une exp\u00e9rimentation pour confirmer la fiabilit\u00e9 des r\u00e9sultats obtenus par biologie mol\u00e9culaire \u00e0 partir de faibles quantit\u00e9s de cibles, comme ceux observ\u00e9s sur le front de la maladie. Cette m\u00e9thode de pi\u00e9geage de spores a\u00e9riennes a alors \u00e9t\u00e9 compar\u00e9e \u00e0 des cartes de pr\u00e9sence de la Chalarose r\u00e9alis\u00e9es gr\u00e2ce \u00e0 des signalements de sympt\u00f4mes. L\u2019\u00e9tude a \u00e9t\u00e9 r\u00e9alis\u00e9e \u00e0 diff\u00e9rentes \u00e9chelles, locale (commune) et r\u00e9gionale, avec des zones d\u2019\u00e9chantillonnage de l\u2019ordre de la 100aine de km sur le front de la Chalarose. Gr\u00e2ce \u00e0 ce travail, nous avons pu d\u00e9terminer un rayon d\u2019action autour de la source d\u2019inoculum \u00e0 l\u2019int\u00e9rieur duquel des strat\u00e9gies de gestion seraient les plus efficaces pour limiter le d\u00e9veloppement de la maladie. Le deuxi\u00e8me objectif de cette th\u00e8se consistait \u00e0 d\u00e9terminer quels facteurs environnementaux influencent le d\u00e9veloppement de la maladie, ce qui s\u2019av\u00e8re \u00eatre un enjeu important pour la gestion foresti\u00e8re et l\u2019avenir du fr\u00eane en tant qu\u2019essence foresti\u00e8re dans les prochaines d\u00e9cennies. Nous avons montr\u00e9 qu\u2019une importante densit\u00e9 d\u2019h\u00f4te et une grande humidit\u00e9 du milieu influencent positivement le d\u00e9veloppement de la maladie. Ce travail a \u00e9galement permis de confirmer sur le terrain la sensibilit\u00e9 de l\u2019agent pathog\u00e8ne aux fortes temp\u00e9ratures estivales, sugg\u00e9rant que la zone \u00e9tudi\u00e9e du sud-est de la France pourrait pr\u00e9senter des \u00e9t\u00e9 trop chauds pour le d\u00e9veloppement de la maladie. A plus large \u00e9chelle, le changement climatique pourrait jouer en faveur des fr\u00eanes. De plus, la pr\u00e9sence d\u2019un effet Allee dans la dynamique de population de l\u2019agent pathog\u00e8ne a \u00e9t\u00e9 sugg\u00e9r\u00e9e par nos r\u00e9sultats exp\u00e9rimentaux. Le dernier objectif de cette th\u00e8se \u00e9tait de mod\u00e9liser la dispersion de la maladie en France. Nos travaux ont permis de mettre en \u00e9vidence une vitesse de dispersion d\u2019environ 60 km \/ an. Un mod\u00e8le de r\u00e9action-diffusion a \u00e9t\u00e9 d\u00e9velopp\u00e9 pour mettre en relation la dispersion, la dynamique de population d\u2019H<\/em>. fraxineus<\/em> et les facteurs environnementaux influen\u00e7ant son d\u00e9veloppement. Ce mod\u00e8le de dispersion qui utilise des donn\u00e9es standards issues du syst\u00e8me d\u2019\u00e9pid\u00e9mio-surveillance forestier du D\u00e9partement de la Sant\u00e9 des For\u00eats apportera des connaissances utiles \u00e0 la mise en place de strat\u00e9gies de gestion. Cette th\u00e8se ouvre des perspectives sur le devenir du fr\u00eane dans un contexte de changement climatique et plus largement sur la gestion des invasions biologiques.<\/p>\n

 <\/p>\n\n\n\n\n
Abstract:<\/strong><\/td>\n<\/tr>\n
Introduction of invasive pathogen fungi is a major cause of forest diseases emergence. For 30 years, a dieback has severely affected ashes and in particular Fraxinus<\/em> excelsior<\/em>. The pathogenic fungus causing the disease is an ascomycete originating from Eastern Asia, Hymenoscyphus fraxineus<\/em>. It was observed for the first time in 90\u2019s in Poland, then rapidly spread over Europe and was reported in France in 2008. The disease is mainly spread by airborne ascospores. The aim of this thesis is to study the epidemiology of H<\/em>. fraxineus<\/em> dispersal by determining environmental factors which impact pathogen development, and by proposing a dispersal model of the disease. The first objective of this thesis was to improve the trapping method of airborne inoculum and then, to use it to study the dispersal pattern of H<\/em>. fraxineus<\/em>. An experiment was set up to confirm the reliability of the molecular biology test for low levels of target such as these observed at the disease front. This trapping method of airborne spores was then compared to maps of disease presence deriving from symptoms reports on ashes. The study was realized at different scales, landscape (village) and regional, with sampling area of about 100 km at the disease front. This work enabled us to determine a radius around inoculum source that would have to be manage for effectively limit the disease development. The second objective of the thesis aimed at determining environmental factors which influence disease development, which is an important issue for forest management and future of ashes in the next decade. We have shown that high host density and high humidity both positively impact disease development. This work confirmed the pathogen susceptibility to high summer temperatures in natural settings and suggests that the climate of Southeastern France should limit disease development. At a larger scale, climate change may work in favor of ashes. Moreover, an Allee effect presence in the population dynamic of H<\/em>. fraxineus<\/em> was suggest by our experimental results. The last objective of this thesis was to model the disease spread in France. Our works estimated the spread speed to 60 km per year. A reaction-diffusion model was developed to link dispersal disease according to H<\/em>. fraxineus<\/em> population dynamic and environmental factors which impact its development. This dispersal model which can use standard data of French forest health surveillance system will provide new knowledge useful to implement management strategies. This thesis offers perspectives on the future of ashes in a context of climate change and more broadly about the management of biological invasions.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Madame Marie GROSDIDIER A brillamment soutenu\u00a0ses travaux de th\u00e8se intitul\u00e9s Epid\u00e9miologie de la Chalarose du fr\u00eane, une maladie caus\u00e9e par l\u2019agent pathog\u00e8ne Hymenoscyphus fraxineus Le vendredi 10 novembre 2017 \u00e0 9h30 Lieu : \u00a0Amphi 7, Campus Aiguillettes, 54506 Vand\u0153uvre-l\u00e8s-Nancy Composition … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-8392","post","type-post","status-publish","format-standard","hentry","category-seminarmeeting"],"_links":{"self":[{"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=\/wp\/v2\/posts\/8392","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8392"}],"version-history":[{"count":0,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=\/wp\/v2\/posts\/8392\/revisions"}],"wp:attachment":[{"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8392"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8392"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8392"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}