{"id":8719,"date":"2018-03-12T11:46:52","date_gmt":"2018-03-12T11:46:52","guid":{"rendered":"https:\/\/mycor.iam.inrae.fr\/IAM\/?p=8719"},"modified":"2018-03-12T11:46:52","modified_gmt":"2018-03-12T11:46:52","slug":"phd-defense-c-lorrain","status":"publish","type":"post","link":"https:\/\/mycor.iam.inrae.fr\/IAM\/?p=8719","title":{"rendered":"PhD defense: C. Lorrain"},"content":{"rendered":"

PhD defense the 28th of March at 1.30 p.m. in the conference room of the INRA center in Champenou<\/em>x.<\/em><\/p>\n

C\u00e9cile Lorrain<\/strong><\/div>\n
<\/div>\n
soutiendra publiquement ses travaux de th\u00e8se portant sur :<\/div>\n
<\/div>\n
L’analyse mol\u00e9culaire de l’interaction peuplier-Melampsora\u00a0<\/em>spp.<\/strong><\/div>\n
<\/div>\n
Dirig\u00e9s par S\u00e9bastien Duplessis et Arnaud Hecker<\/div>\n
le 28 mars\u00a0\u00e0 13h30<\/div>\n
Salle de conf\u00e9rence<\/div>\n
Centre INRA Grand Est – Nancy<\/div>\n
Champenoux<\/div>\n

R\u00e9sum\u00e9:<\/strong><\/p>\n

La maladie de la rouille foliaire du peuplier est caus\u00e9e par des esp\u00e8ces de champignons de la famille des Melampsoraceae et de l’ordre des Pucciniales. Trois esp\u00e8ces infectent principalement les peupleraies en France :\u00a0Melampsora larici-populina<\/em>\u00a0qui est la plus agressive,\u00a0Melampsora allii-populina<\/em>\u00a0et\u00a0Melampsora medusae\u00a0<\/em>f. sp.\u00a0deltoidae<\/em>. Dans leurs cycles de vie, ces trois esp\u00e8ces partagent les peupliers comme h\u00f4tes communs pour assurer leur multiplication clonale au cours de l’\u00e9t\u00e9 et elles infectent des h\u00f4tes diff\u00e9rents pour r\u00e9aliser leur cycle sexu\u00e9 au cours du printemps. Chez les champignons pathog\u00e8nes biotrophes obligatoires comme les Pucciniales, la s\u00e9cr\u00e9tion de mol\u00e9cules appel\u00e9es effecteurs conditionne le succ\u00e8s d’infection de la plante h\u00f4te. Ainsi, les effecteurs permettent de manipuler les fonctions cellulaires de l\u2019h\u00f4te et de contourner son syst\u00e8me immunitaire. Comprendre le r\u00f4le fondamental de ces mol\u00e9cules dans la cellule-h\u00f4te est une des questions cl\u00e9s de la biologie des effecteurs. Au cours de cette th\u00e8se, des approches de g\u00e9nomique, de transcriptomique et de caract\u00e9risation fonctionnelle et structurale d’effecteurs candidats ont \u00e9t\u00e9 d\u00e9ploy\u00e9es afin de contribuer \u00e0 l\u2019analyse mol\u00e9culaire de l\u2019interaction entre peupliers et\u00a0Melampsora<\/em>\u00a0spp. Premi\u00e8rement, l\u2019analyse du transcriptome de\u00a0M. larici-populina\u00a0<\/em>au cours de son cycles sexu\u00e9 a mis en \u00e9vidence que les prot\u00e9ines s\u00e9cr\u00e9t\u00e9es sont surrepr\u00e9sent\u00e9es parmi les g\u00e8nes surexprim\u00e9s dans les basides et au cours de l\u2019infection de l’h\u00f4te m\u00e9l\u00e8ze. La comparaison des transcriptomes de\u00a0M. larici-populina\u00a0<\/em>lors de l’infection des deux h\u00f4tes, le peuplier et le m\u00e9l\u00e8ze, r\u00e9v\u00e8le la pr\u00e9sence d’une majorit\u00e9 de g\u00e8nes exprim\u00e9s commun\u00e9ment chez les deux h\u00f4tes et une fraction exprim\u00e9e sp\u00e9cifiquement chez chacun des deux h\u00f4tes. Ainsi, nous r\u00e9v\u00e9lons des g\u00e8nes codant de petites prot\u00e9ines s\u00e9cr\u00e9t\u00e9es qui pourraient \u00eatre associ\u00e9s \u00e0 la sp\u00e9cificit\u00e9 d’h\u00f4te. Deuxi\u00e8mement, le s\u00e9quen\u00e7age du g\u00e9nome de\u00a0M. allii-populina<\/em>\u00a0et sa comparaison au g\u00e9nome de\u00a0M. larici-populina\u00a0<\/em>a r\u00e9v\u00e9l\u00e9 une expansion de sa taille (336 Mb contre 110 Mb). Cette derni\u00e8re est associ\u00e9e \u00e0 l\u2019invasion du g\u00e9nome par de nombreux \u00e9l\u00e9ments transposables qui repr\u00e9sentent pr\u00e8s de 75% du g\u00e9nome et par un enrichissement en g\u00e8nes par rapport \u00e0\u00a0M. larici-populina<\/em>\u00a0(23\u00a0089 g\u00e8nes contre 19\u00a0550). Cependant, les r\u00e9pertoires de g\u00e8nes potentiellement impliqu\u00e9s dans le processus infectieux sont proportionnellement sensiblement similaires entre les deux esp\u00e8ces. Les quelques diff\u00e9rences observ\u00e9es pourraient \u00eatre associ\u00e9es \u00e0 la sp\u00e9cificit\u00e9 d’h\u00f4te (Populus<\/em>\u00a0spp.\/Larix\u00a0<\/em>spp. dans un cas et\u00a0Populus\u00a0<\/em>spp.\/Allium<\/em>\u00a0spp. dans l’autre) et \u00e0 l’adaptation \u00e0 des h\u00f4tes alternants diff\u00e9rents. Troisi\u00e8mement, des cribles effectoromiques r\u00e9alis\u00e9s sur un r\u00e9pertoire d\u2019effecteurs candidats de\u00a0M. larici-populina\u00a0<\/em>ont r\u00e9v\u00e9l\u00e9 deux candidats d\u2019int\u00e9r\u00eat. Nous avons mis en place des approches fonctionnelles pour tenter d’\u00e9lucider leur r\u00f4le dans l’interaction avec le peuplier. Nous avons ainsi pu produire l’effecteur MLP124017 qui interagit avec des prot\u00e9ines de la famille Topless-related proteins et r\u00e9soudre sa structure tridimensionnelle qui pr\u00e9sente une similarit\u00e9 \u00e0 des prot\u00e9ines nuclear transport factor 2 like qui sont des prot\u00e9ines cargo transportant diverses mol\u00e9cules entre le noyau et le cytoplasme. L’effecteur Chloroplast-Targeted Protein MLPCTP1 est adress\u00e9 vers et est localis\u00e9 dans les chloroplastes\u00a0via<\/em>\u00a0un peptide de transit dans le syst\u00e8me h\u00e9t\u00e9rologue\u00a0Nicotiana benthamiana<\/em>\u00a0et nous montrons une localisation similaire chez le peuplier et l’arabette. Les fonctions de ces effecteurs restent encore \u00e0 d\u00e9terminer mais les travaux amorc\u00e9s dans cette th\u00e8se ouvrent de nouvelles perspectives quant \u00e0 la diversit\u00e9 et au r\u00f4le des effecteurs chez les Pucciniales.<\/p>\n

Abstract:<\/strong><\/p>\n

The poplar rust disease is caused by fungi belonging to the order Pucciniales in the family Melamsporaceae. Three main species cause damages in poplar plantations in France:\u00a0Melampsora larici-populina<\/em>, which is the most aggressive,\u00a0Melampsora allii-populina<\/em>\u00a0and\u00a0Melampsora medusae\u00a0<\/em>f. sp.\u00a0deltoidae<\/em>. During their life cycles, these three fungi share poplars as main host in which they achieve their clonal multiplication during summer and they infect different alternate hosts to complete their sexual reproduction in spring. In fungal obligate biotrophs like rust fungi, the success of host infection is conditioned by the secretion of molecules called effectors. Effectors allow the pathogen to manipulate host cell processes and to evade the plant immune system. A key question in effector biology is to understand how these molecules function in the host cell. In the frame of this PhD thesis, genomics, transcriptomics, functional and structural approaches were used to contribute to the molecular analysis of the poplar-Melamspora<\/em>\u00a0spp. interaction. Firstly, the transcriptome analysis of\u00a0M. larici-populina<\/em>\u00a0during its sexual cycle highlighted that small-secreted proteins were over-represented among genes up-regulated in basidia and during larch infection. Comparison of\u00a0M. larici-populina<\/em>\u00a0transcriptomes during infection of the two hosts, poplar and larch, revealed that a majority of the genes are commonly expressed on both hosts and a fraction is specifically expressed on each host. Small-secreted protein genes specifically expressed on each host maybe related to host specificity. Secondly, the sequencing of the\u00a0M.\u00a0allii-populina<\/em>\u00a0genome and the comparison with\u00a0M. larici-populina<\/em>\u00a0revealed a size expansion in\u00a0M. allii-populina<\/em>\u00a0(336Mb\u00a0vs.<\/em>\u00a0110Mb). This expansion is mostly due to the invasion of the genome by numerous transposable elements that represent more than 75% of the genome and by a gene enrichment compared to\u00a0M. larici-populina<\/em>\u00a0(23,089 and 19,550 genes, respectively). However, catalogues of gene potentially involved in the infection process are proportionally similar between the two species. The few differences observed could be linked to host specificity (Populus<\/em>\u00a0spp.\/Larix\u00a0<\/em>spp. on one hand and\u00a0Populus\u00a0<\/em>spp.\/Allium<\/em>\u00a0spp. on the other hand) and adaptation to their different hosts. Thirdly, effectoromic screens developed on a panel of\u00a0M. larici-populina<\/em>\u00a0candidate effectors revealed two candidates of interest. We set up a pipeline of functional approaches in order to elucidate their role in the interaction with poplar. We produced the candidate effector MLP124017 that interacts with proteins of the Topless-related proteins family and solved its structure that presents similarities with nuclear transport factor 2 like proteins. These proteins are cargos that transport diverse molecules between the nucleus and cytosol in plant cells. The effector Chloroplast-Targeted Protein MLPCTP1 is addressed and translocated inside chloroplasts through a transit peptide in the heterologous system\u00a0Nicotianana benthamiana<\/em>\u00a0and we showed that the same localization occurs in poplar and in Arabidopsis. The functions of these two effectors remain to be determined but the functional characterization initiated in this thesis opens new perspectives in term of diversity and roles of effectors in rust fungi.<\/p>\n","protected":false},"excerpt":{"rendered":"

PhD defense the 28th of March at 1.30 p.m. in the conference room of the INRA center in Champenoux. C\u00e9cile Lorrain soutiendra publiquement ses travaux de th\u00e8se portant sur : L’analyse mol\u00e9culaire de l’interaction peuplier-Melampsora\u00a0spp. Dirig\u00e9s par S\u00e9bastien Duplessis et … 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":[4,8],"tags":[],"class_list":["post-8719","post","type-post","status-publish","format-standard","hentry","category-seminarmeeting","category-thesis"],"_links":{"self":[{"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=\/wp\/v2\/posts\/8719","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=8719"}],"version-history":[{"count":0,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=\/wp\/v2\/posts\/8719\/revisions"}],"wp:attachment":[{"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8719"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8719"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mycor.iam.inrae.fr\/IAM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8719"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}