Anne Sicard - Profile on Academia.edu (original) (raw)
Papers by Anne Sicard
Rice, Jul 31, 2023
Bacterial Leaf Blight of rice (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major thre... more Bacterial Leaf Blight of rice (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major threat for food security in many rice growing countries including Burkina Faso, where the disease was first reported in the 1980's. In line with the intensification of rice cultivation in West-Africa, BLB incidence has been rising for the last 15 years. West-African strains of Xoo differ from their Asian counterparts as they (i) are genetically distant, (ii) belong to new races and, (iii) contain reduced repertoires of Transcription Activator Like (TAL) effector genes. In order to investigate the evolutionary dynamics of Xoo populations in Burkina Faso, 177 strains were collected from 2003 to 2018 in three regions where BLB is occurring. Multilocus VNTR Analysis (MLVA-14) targeting 10 polymorphic loci discriminated 24 haplotypes and showed that Xoo populations were structured according to their geographical localization and year of collection. Considering their major role in Xoo pathogenicity, we assessed the TAL effector repertoires of the 177 strains upon RFLP-based profiling. Surprisingly, an important diversity was revealed with up to eight different RFLP patterns. Finally, comparing neutral vs. tal effector gene diversity allowed to suggest scenarios underlying the evolutionary dynamics of Xoo populations in Burkina Faso, which is key to rationally guide the deployment of durably resistant rice varieties against BLB in the country.
Determinants of Xylella fastidiosa adaptation to olive trees in Italy
HAL (Le Centre pour la Communication Scientifique Directe), 2020
How to test if disrupting Xylella fastidiosa-vector interactions can control disease spread?
HAL (Le Centre pour la Communication Scientifique Directe), 2016
Author response: A multicellular way of life for a multipartite virus
The strange biology of multipartite viruses
HAL (Le Centre pour la Communication Scientifique Directe), Mar 19, 2015
International audienc
¿ Qué sabemos y qué no dicen los genomas de Xylella fastidiosa ?
HAL (Le Centre pour la Communication Scientifique Directe), 2018
Qué sabemos de Xylella fastidiosa y qué nos dicen sus genomas
Phytoma España: La revista profesional de sanidad vegetal, 2018
Los genomas contienen informacion importante sobre aspectos fundamentales de la biologia de un or... more Los genomas contienen informacion importante sobre aspectos fundamentales de la biologia de un organismo, de su historia y su potencial evolutivos; informan, por ejemplo, de su capacidad para adaptarse a nuevos entornos. Tras el brote de Xylella fastidiosa en Brasil en 1987 y las consecuencias devastadoras que este tuvo en los citricos, se llevo a cabo la secuenciacion del genoma de Xf en 2000, con lo que paso a ser la primera bacteria fitopatogena con genoma secuenciado. Tres anos mas tarde, se secuenciaron los genomas de otras tres cepas de Xf, entre ellas el de la cepa causante de la enfermedad de Pierce, una enfermedad de la vid que todavia hoy genera gastos de 104 millones de dolares al ano en California, EE. UU. (1,11). Estos datos supusieron los primeros pasos hacia el conocimiento de la genomica de Xf. Simultaneamente, Scally y col desarrollaron la tecnica de la tipificacion multilocus de secuencias (MLST, por sus siglas en ingles) de esta bacteria y sentaron de este modo las bases para la caracterizacion de la diversidad genetica, la ecologia y la historia evolutiva de Xf. Este articulo tiene como objetivo proporcionar un breve repaso de los conocimientos adquiridos gracias a los analisis genomicos de Xylella fastidiosa, ademas de poner de relieve algunas de las lagunas que aun existen en este campo.
New concepts in the biology of multipartite viruses
HAL (Le Centre pour la Communication Scientifique Directe), Jun 7, 2015
International audienc
A mulicellular lifestyle for a multipartite virus
HAL (Le Centre pour la Communication Scientifique Directe), Oct 1, 2018
International audienc
Zenodo (CERN European Organization for Nuclear Research), Jul 17, 2019
Xylella fastidiosa is an economically important bacterial plant pathogen. With insights gained fr... more Xylella fastidiosa is an economically important bacterial plant pathogen. With insights gained from 72 genomes, this study investigated differences among the three main subspecies, which have allopatric origins: X. fastidiosa subsp. fastidiosa, multiplex, and pauca. The origin of recombinogenic X. fastidiosa subsp. morus and sandyi was also assessed. The evolutionary rate of the 622 genes of the species core genome was estimated at the scale of an X. fastidiosa subsp. pauca subclade (7.62 ϫ 10 Ϫ7 substitutions per site per year), which was subsequently used to estimate divergence time for the subspecies and introduction events. The study characterized genes present in the accessory genome of each of the three subspecies and investigated the core genome to detect genes potentially under positive selection. Recombination is recognized to be the major driver of diversity in X. fastidiosa, potentially facilitating shifts to novel plant hosts. The relative effect of recombination in comparison to point mutation was calculated (r/m ϭ 2.259). Evidence of recombination was uncovered in the core genome alignment; X. fastidiosa subsp. fastidiosa in the United States was less prone to recombination, with an average of 3.22 of the 622 core genes identified as recombining regions, whereas a specific clade of X. fastidiosa subsp. multiplex was found to have on average 9.60 recombining genes, 93.2% of which originated from X. fastidiosa subsp. fastidiosa. Interestingly, for X. fastidiosa subsp. morus, which was initially thought to be the outcome of genome-wide recombination between X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. multiplex, intersubspecies homologous recombination levels reached 15.30% in the core genome. Finally, there is evidence of X. fastidiosa subsp. pauca strains from citrus containing genetic elements acquired from strains infecting coffee plants as well as genetic elements from both X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. multiplex. In summary, our data provide new insights into the evolution and epidemiology of this plant pathogen. IMPORTANCE Xylella fastidiosa is an important vector-borne plant pathogen. We used a set of 72 genomes that constitutes the largest assembled data set for this bacterial species so far to investigate genetic relationships and the impact of recombination on phylogenetic clades and to compare genome content at the subspecies level, and we used a molecular dating approach to infer the evolutionary rate of X. fastidiosa. The results demonstrate that recombination is important in shaping the genomes of X. fastidiosa and that each of the main subspecies is under different selective pressures. We hope insights from this study will improve our understanding of X. fastidiosa evolution and biology.
Progression of Xylella fastidiosa infection in grapevines under field conditions
Phytopathology®
The pathogen Xylella fastidiosa subspecies fastidiosa has circulated through California’s vineyar... more The pathogen Xylella fastidiosa subspecies fastidiosa has circulated through California’s vineyards since its introduction from Central America in the 1800s. This pathogen is responsible for a bacterial disease called Pierce’s disease of grapevine (PD). With no known cure, PD has had devastating effects on some vineyards. Important factors that impact disease severity and persistence include: the presence of insect vectors, grapevine cultivar, management, ecology, and winter temperatures. Removal of infected vines is critical for reducing pathogen spread, but relies on accurate and rapid pathogen detection. In this study, we foster a greater understanding of disease symptom emergence by way of a three-year field inoculation project in Napa Valley. Although PD emergence and symptom progression have been studied in greenhouse and experimental plots, there is a large knowledge gap in quantifying disease progression under commercial conditions. After inoculating 80 mature Vitis vinifera...
HAL (Le Centre pour la Communication Scientifique Directe), Apr 1, 2020
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires Anses • rapport d'appui scientifique et technique Demande « n°2018-SA-0248 Lutte Xylella fastiosa PACA » page 3 / 35 avril 2020 Présentation des intervenants PRÉAMBULE : Les experts, membres de comités d'experts spécialisés, de groupes de travail ou désignés rapporteurs sont tous nommés à titre personnel, intuitu personae, et ne représentent pas leur organisme d'appartenance. GROUPE DE TRAVAIL Président M. Eric VERDIN-Ingénieur de recherche, INRAE Avignon, virologie et épidémiologie. Membres Mme Anne SICARD-Chercheur Post-doctoral, IRD Montpellier, bactériologie, virologie.
Exploiting a chitinase to suppress Xylella fastidiosa colonization of plants and insects
HAL (Le Centre pour la Communication Scientifique Directe), 2016
The lifestyle of a multipartite virus challenges major paradigms in Virology
International audienc
The question of modularity in the genome of multipartite viruses
International audienc
A pluricellular way of life for multipartite viruses
International audienc
Multipartite viruses in plants and intercellular communication
International audienc
Gene copy number variations during the life cycle of a multipartite virus
International audienc
Variable gene copy number in a multipartite viral genome
International audienc
Circulative non-propagative transmission in Nanoviruses: an oversimplified view?
National audienc
Rice, Jul 31, 2023
Bacterial Leaf Blight of rice (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major thre... more Bacterial Leaf Blight of rice (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major threat for food security in many rice growing countries including Burkina Faso, where the disease was first reported in the 1980's. In line with the intensification of rice cultivation in West-Africa, BLB incidence has been rising for the last 15 years. West-African strains of Xoo differ from their Asian counterparts as they (i) are genetically distant, (ii) belong to new races and, (iii) contain reduced repertoires of Transcription Activator Like (TAL) effector genes. In order to investigate the evolutionary dynamics of Xoo populations in Burkina Faso, 177 strains were collected from 2003 to 2018 in three regions where BLB is occurring. Multilocus VNTR Analysis (MLVA-14) targeting 10 polymorphic loci discriminated 24 haplotypes and showed that Xoo populations were structured according to their geographical localization and year of collection. Considering their major role in Xoo pathogenicity, we assessed the TAL effector repertoires of the 177 strains upon RFLP-based profiling. Surprisingly, an important diversity was revealed with up to eight different RFLP patterns. Finally, comparing neutral vs. tal effector gene diversity allowed to suggest scenarios underlying the evolutionary dynamics of Xoo populations in Burkina Faso, which is key to rationally guide the deployment of durably resistant rice varieties against BLB in the country.
Determinants of Xylella fastidiosa adaptation to olive trees in Italy
HAL (Le Centre pour la Communication Scientifique Directe), 2020
How to test if disrupting Xylella fastidiosa-vector interactions can control disease spread?
HAL (Le Centre pour la Communication Scientifique Directe), 2016
Author response: A multicellular way of life for a multipartite virus
The strange biology of multipartite viruses
HAL (Le Centre pour la Communication Scientifique Directe), Mar 19, 2015
International audienc
¿ Qué sabemos y qué no dicen los genomas de Xylella fastidiosa ?
HAL (Le Centre pour la Communication Scientifique Directe), 2018
Qué sabemos de Xylella fastidiosa y qué nos dicen sus genomas
Phytoma España: La revista profesional de sanidad vegetal, 2018
Los genomas contienen informacion importante sobre aspectos fundamentales de la biologia de un or... more Los genomas contienen informacion importante sobre aspectos fundamentales de la biologia de un organismo, de su historia y su potencial evolutivos; informan, por ejemplo, de su capacidad para adaptarse a nuevos entornos. Tras el brote de Xylella fastidiosa en Brasil en 1987 y las consecuencias devastadoras que este tuvo en los citricos, se llevo a cabo la secuenciacion del genoma de Xf en 2000, con lo que paso a ser la primera bacteria fitopatogena con genoma secuenciado. Tres anos mas tarde, se secuenciaron los genomas de otras tres cepas de Xf, entre ellas el de la cepa causante de la enfermedad de Pierce, una enfermedad de la vid que todavia hoy genera gastos de 104 millones de dolares al ano en California, EE. UU. (1,11). Estos datos supusieron los primeros pasos hacia el conocimiento de la genomica de Xf. Simultaneamente, Scally y col desarrollaron la tecnica de la tipificacion multilocus de secuencias (MLST, por sus siglas en ingles) de esta bacteria y sentaron de este modo las bases para la caracterizacion de la diversidad genetica, la ecologia y la historia evolutiva de Xf. Este articulo tiene como objetivo proporcionar un breve repaso de los conocimientos adquiridos gracias a los analisis genomicos de Xylella fastidiosa, ademas de poner de relieve algunas de las lagunas que aun existen en este campo.
New concepts in the biology of multipartite viruses
HAL (Le Centre pour la Communication Scientifique Directe), Jun 7, 2015
International audienc
A mulicellular lifestyle for a multipartite virus
HAL (Le Centre pour la Communication Scientifique Directe), Oct 1, 2018
International audienc
Zenodo (CERN European Organization for Nuclear Research), Jul 17, 2019
Xylella fastidiosa is an economically important bacterial plant pathogen. With insights gained fr... more Xylella fastidiosa is an economically important bacterial plant pathogen. With insights gained from 72 genomes, this study investigated differences among the three main subspecies, which have allopatric origins: X. fastidiosa subsp. fastidiosa, multiplex, and pauca. The origin of recombinogenic X. fastidiosa subsp. morus and sandyi was also assessed. The evolutionary rate of the 622 genes of the species core genome was estimated at the scale of an X. fastidiosa subsp. pauca subclade (7.62 ϫ 10 Ϫ7 substitutions per site per year), which was subsequently used to estimate divergence time for the subspecies and introduction events. The study characterized genes present in the accessory genome of each of the three subspecies and investigated the core genome to detect genes potentially under positive selection. Recombination is recognized to be the major driver of diversity in X. fastidiosa, potentially facilitating shifts to novel plant hosts. The relative effect of recombination in comparison to point mutation was calculated (r/m ϭ 2.259). Evidence of recombination was uncovered in the core genome alignment; X. fastidiosa subsp. fastidiosa in the United States was less prone to recombination, with an average of 3.22 of the 622 core genes identified as recombining regions, whereas a specific clade of X. fastidiosa subsp. multiplex was found to have on average 9.60 recombining genes, 93.2% of which originated from X. fastidiosa subsp. fastidiosa. Interestingly, for X. fastidiosa subsp. morus, which was initially thought to be the outcome of genome-wide recombination between X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. multiplex, intersubspecies homologous recombination levels reached 15.30% in the core genome. Finally, there is evidence of X. fastidiosa subsp. pauca strains from citrus containing genetic elements acquired from strains infecting coffee plants as well as genetic elements from both X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. multiplex. In summary, our data provide new insights into the evolution and epidemiology of this plant pathogen. IMPORTANCE Xylella fastidiosa is an important vector-borne plant pathogen. We used a set of 72 genomes that constitutes the largest assembled data set for this bacterial species so far to investigate genetic relationships and the impact of recombination on phylogenetic clades and to compare genome content at the subspecies level, and we used a molecular dating approach to infer the evolutionary rate of X. fastidiosa. The results demonstrate that recombination is important in shaping the genomes of X. fastidiosa and that each of the main subspecies is under different selective pressures. We hope insights from this study will improve our understanding of X. fastidiosa evolution and biology.
Progression of Xylella fastidiosa infection in grapevines under field conditions
Phytopathology®
The pathogen Xylella fastidiosa subspecies fastidiosa has circulated through California’s vineyar... more The pathogen Xylella fastidiosa subspecies fastidiosa has circulated through California’s vineyards since its introduction from Central America in the 1800s. This pathogen is responsible for a bacterial disease called Pierce’s disease of grapevine (PD). With no known cure, PD has had devastating effects on some vineyards. Important factors that impact disease severity and persistence include: the presence of insect vectors, grapevine cultivar, management, ecology, and winter temperatures. Removal of infected vines is critical for reducing pathogen spread, but relies on accurate and rapid pathogen detection. In this study, we foster a greater understanding of disease symptom emergence by way of a three-year field inoculation project in Napa Valley. Although PD emergence and symptom progression have been studied in greenhouse and experimental plots, there is a large knowledge gap in quantifying disease progression under commercial conditions. After inoculating 80 mature Vitis vinifera...
HAL (Le Centre pour la Communication Scientifique Directe), Apr 1, 2020
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires Anses • rapport d'appui scientifique et technique Demande « n°2018-SA-0248 Lutte Xylella fastiosa PACA » page 3 / 35 avril 2020 Présentation des intervenants PRÉAMBULE : Les experts, membres de comités d'experts spécialisés, de groupes de travail ou désignés rapporteurs sont tous nommés à titre personnel, intuitu personae, et ne représentent pas leur organisme d'appartenance. GROUPE DE TRAVAIL Président M. Eric VERDIN-Ingénieur de recherche, INRAE Avignon, virologie et épidémiologie. Membres Mme Anne SICARD-Chercheur Post-doctoral, IRD Montpellier, bactériologie, virologie.
Exploiting a chitinase to suppress Xylella fastidiosa colonization of plants and insects
HAL (Le Centre pour la Communication Scientifique Directe), 2016
The lifestyle of a multipartite virus challenges major paradigms in Virology
International audienc
The question of modularity in the genome of multipartite viruses
International audienc
A pluricellular way of life for multipartite viruses
International audienc
Multipartite viruses in plants and intercellular communication
International audienc
Gene copy number variations during the life cycle of a multipartite virus
International audienc
Variable gene copy number in a multipartite viral genome
International audienc
Circulative non-propagative transmission in Nanoviruses: an oversimplified view?
National audienc