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The exposure of adult, female, Mediterranean goats during anoestrus to males with induced sexual activity via photostimulation, induces a very high percentage of ovulations. The present work examines the ability of photostimulated bucks to improve the male effect-induced reproductive response of young does over that induced by non-stimulated bucks. A 2×2 factorial experiment was designed, consisting of doe age and buck photoperiod treatments. During seasonal anoestrus, 41 does aged 7 (n=19) or 10 (n=22) months were subjected to the male effect on 10 April; half of each group was exposed to males rendered sexually active by prior exposure to 3 months of long days (16 h of light/day) from 31 October (PHOTO bucks), and half to males maintained under the natural photoperiod (CONTROL bucks). Oestrous activity was recorded daily by direct visual observation of the marks left by male-worn marking harnesses over the 32 days following the bringing of the sexes together (introduction). Doe body weight and body condition were determined weekly. Ovulation was detected by measuring plasma progesterone concentrations twice per week over the 3 weeks after introduction. The ovulation rate was assessed by transrectal ultrasonography. Fecundity, fertility, prolificacy and productivity were also determined. The interaction doe age × buck photoperiod treatment had no effect on any outcome. The percentage of females showing ovulation or oestrus was higher in the does exposed to PHOTO bucks (85% v. 43% for those exposed to CONTROL bucks) they also showed higher fertility (75% v. 43%) and productivity (1.05±0.17 v. 0.57±0.16 kids born per doe serviced) (all P values at least P, This study was funded by Grant AGL2016-75848-R from MINECO-AEI-FEDER (Spain). Thanks are also owed to CEICamBio for their support.This study was funded by Grant AGL2016-75848-R from MINECO-AEI-FEDER (Spain). Thanks are also owed to CEI CamBio for their support.

International audience; In this work, we propose a mathematical pathogen-host model which focused on the epidemiological cycle of banana black leaf streak disease and which takes into account control strategies to reduce the spores production ,this mainly thanks to an differential equations system with time delay in wich, the host dynamics is coupled to that of the fungus responsible for the disease. By using optimal control theory, we show that an optimal control exists for this problem and Pontryagin's maximum principle is used to characterize an optimal control. Numerical simulations are provided to illustrate our results.; Dans ce travail, nous proposons un modèle mathématiques hôte-pathogène axé sur le cycle épidémiologique de la maladie des raies noires du bananier et prenant en compte les stratégies de contrôle pour réduire la production des spores, ceci à partir d'un système d'équations différen-tielles avec retard dans lequel la dynamique de la plante hôte est couplé avec celle du champignon responsable de la maladie. En utilisant la théorie du contrôle optimal, nous montrons qu'un contrôle optimal existe pour ce problème et le principe du maximum de Pontryagin est utilisé pour caractériser ce contrôle optimal. Des simulations numériques sont faites pour illustrer nos résultats.

International audience; Because epidemics of successive cropping seasons are not independent, epidemiological studies need to encompass the processes occurring during the transmission of epidemics from one season to the next. With Leptosphaeria maculans, infected stubble allows carry-over of the fungus. Generation experiments using recurrent selection on field plots are a useful means of comparing the effects of selection pressures. However, the full life cycle of the fungus, from plant infection to the next generation of ascospores, has not yet been achieved under controlled conditions. Studies were undertaken to achieve an experimental set-up with sexual reproduction under controlled conditions. Cankered oilseed rape stems were produced under controlled conditions, after inoculation with a mixture of 12 isolates across both mating types. Stems were cut longitudinally and attached to styropore plates. Stem halves were incubated outside or in climate chambers regularly soaked in tap water to ensure maturation. Incubation was stopped when mature pseudothecia were observed. In all three independent experiments, more stem halves had pseudothecia when incubated under controlled conditions (30-100%) than incubated outside (0-80%). To the authors' knowledge, this is the first study achieving the full life cycle of the fungus under controlled conditions, from infection of the plant to mature pseudothecia. This opens up the prospect of running experiments year-round to better understand inoculum production, to compare fungal fitness, or to run generation experiments with exotic pathogen populations.

Summary Microalgae play a major role as primary producers in aquatic ecosystems. Cell signalling regulates their interactions with the environment and other organisms, yet this process in phytoplankton is poorly defined. Using the marine planktonic diatom Pseudo‐nitzschia multistriata, we investigated the cell response to cues released during sexual reproduction, an event that demands strong regulatory mechanisms and impacts on population dynamics.We sequenced the genome of P. multistriata and performed phylogenomic and transcriptomic analyses, which allowed the definition of gene gains and losses, horizontal gene transfers, conservation and evolutionary rate of sex‐related genes. We also identified a small number of conserved noncoding elements.Sexual reproduction impacted on cell cycle progression and induced an asymmetric response of the opposite mating types. G protein‐coupled receptors and cyclic guanosine monophosphate (cGMP) are implicated in the response to sexual cues, which overall entails a modulation of cell cycle, meiosis‐related and nutrient transporter genes, suggesting a fine control of nutrient uptake even under nutrient‐replete conditions.The controllable life cycle and the genome sequence of P. multistriata allow the reconstruction of changes occurring in diatoms in a key phase of their life cycle, providing hints on the evolution and putative function of their genes and empowering studies on sexual reproduction.

The coffee berry borer, Hypothenemus hampei (Ferrari), is a major insect pest of coffee crops worldwide. As part of a program of studies aimed at efficient and sustainable pest control, a study was conducted to determine the mating status of adult females in the broader context of studying pest dispersal behavior. To that end, it was deemed important to determine the morphology of the H. hampei female reproductive tract. This study focused on direct observation of the spermatheca of unmated, and colonizing adult females obtained from natural field populations with a high probability of having mated, and the description of all organs of the reproductive tract using established standard staining and microscopy techniques. Spermathecae were extracted from the samples and sorted according to their origin (unmated or colonizing females). The morphology of sperm present in the female spermathecae was compared with that of sperm taken directly from male testes. Two staining techniques using Giemsa and chlorazol black allowed spermatheca and sperm to be distinguished from other tissues. Under these conditions, a more precise description of the spermatheca was achieved, including the spermathecal duct and spermathecal muscles, spermathecal gland, and, for the first time, sperm when present. These techniques permitted the accurate and rapid determination of the presence or absence of sperm in the spermathecae of H. hampei females, thereby establishing their mating status. (Resume d'auteur)

Parasitism is a frequent lifestyle in nature and a major source of evolutionary pressure for both hosts and their parasites. Dinoflagellates are successful marine protists found in oceans worldwide, some of which are responsible for toxic blooms while others live in mutualistic relationships with myriad of corals. Amoebophrya ceratii species complex (Syndiniales) includes a large number of parasites which have the potential for regulating dinoflagellate blooms. A high sequence diversity has been observed for this group in both cultures and environmental investigations. This thesis was aimed to answer whether the sequence diversity represents the species diversity. Based on a polyphasic approach involving genetic and phenotypic characters applied on 119 closely related individuals, all able to infect the same host species (the bloom-forming dinoflagellate Scrippsiella trochoidea), I defined 8 ribotypes which likely correspond to different species. These results advocated for considering unique sequences (i.e., with any nucleotide differences) of 18S-V4 or 18S-V9 (small subunit ribosomal RNA genes) regions for species delimitation rather than grouping them into operational taxonomic units (OTUs). Then I investigated the existence of a set of genes specifically involved in meiosis in two fully sequenced genomes and thereby provided the in silico evidence that sexual reproduction may occur in Amoebophrya. I observed that these genes over-expressed during the free-living stage of the parasite, providing an interesting track to explore. Overall, this thesis offers new insights into the highly underestimated species diversity in Amoebophyra lineage and lays the basis for further study on their biological traits.; Le parasitisme est un style de vie fréquent dans la nature, et une force évolutive majeure pour les hôtes comme pour les parasites. Les dinoflagellés sont des protistes marins très répandus dans tous les océans, certaines espèces étant même responsables d’efflorescences algales toxiques tandis que d’autres vivent en symbioses mutualistes avec de nombreux coraux. Le complexe d’espèces Amoebophrya ceratii (Syndiniales) inclut de très nombreux parasites de dinoflagellés capables potentiellement de contrôler les efflorescences de ces dinoflagellés. Une très grande diversité a été observée au sein de ce groupe, soit en culture soit dans l’environnement. Ce travail de thèse a pour but d’étudier si la diversité de ces séquences correspond à la diversité au niveau spécifique. Sur la base d’une approche polyphasique faisant intervenir des caractères génétiques et phénotypiques appliqués à 119 individus proches phylogénétiquement, et tous capables d’infecter le même hôte (le dinoflagellé producteur d’efflorescence Scrippsiella trochoidea), j’ai défini 8 ribotypes qui correspondent vraisemblablement à des espèces différentes. Ces résultats prônent l’utilisation de séquences uniques (i.e., divergentes par un seul nucléotide) pour délimiter les espèces dans la région V4 ou V9 du 18S (la petite sous-unité du ribosome) plutôt que de les grouper en unité opérationnelle taxonomique (OTUs). J’ai ensuite recherché l’existence d’une collection de gènes spécifiquement impliqués dans la méiose au sein de deux génomes de référence, et fournit des évidences in silico qu’une reproduction sexuée peut avoir lieu chez ce parasite. J’ai observé que ces gènes étaient surexprimés durant la phase libre du parasite, offrant une piste intéressante pour de prochaines études. En conclusion, ce travail de thèse offre de nouvelles perspectives concernant la diversité largement sous-estimée des Amoebophrya et posent de nouvelles bases pour l’étude de leurs traits biologiques.

National audience

Effects of exposure to diesel exhaust during pregnancy on feto-placental and offspring development using a rabbit model. 66. Annual Scientific Meeting of the Society for Reproductive Investigation

Naissance après AMP : l’apport des modèles animaux !. Journées GynFoch

Temperature in the progamic phase is critical for the success of plant sexual reproduction, and new knowledge is needed to optimise breeding programmes to obtain new varieties that adapt to a climate change scenario. Using three male donors and one female recipient in the genus Citrus, we evaluated the effect of four temperature regimes on each process in the progamic phase. An innovative method based on microscopic observations of cross sections from pollinated pistils collected daily allowed a comprehensive analysis of pollen tube growth (dynamics and kinetics) along the pistil. Pollen grain germination and stigmatic receptivity were evaluated directly on the stigma, which offers more accurate information than previously reported in vitro experiments. Our results showed that warm temperatures reduce the time needed by pollen tubes to reach ovules and accelerate pistil degeneration, while cold temperatures produce the opposite effects. Interestingly, we observed both pollen grain germination and pollen tube growth at 10 °C, which have not been observed in previous studies in citrus. At this temperature, the differences observed in both pollen grain germination and pollen tube growth for different genotypes reflect the adaptation of their sporophytic generation to low temperatures which would enable gametophytic screening to be used as a tool to select better adapted genotypes to different temperature conditions. The differences observed in the growth rates between pollen tubes in each genotype-temperature combination provide an opportunity to explore additional gametophytic selection in this reproductive phase. The capacity to respond to temperature changes in the progamic phase to ensure mating can be useful for breeding programs that focus on obtaining better adapted populations to different temperature conditions.

Gonad differentiation is a crucial step conditioning the future fertility of individuals and most of the master genes involved in this process have been investigated in detail. However, transcriptomic analyses of developing gonads from different animal models have revealed that hundreds of genes present sexually dimorphic expression patterns. DMXL2 was one of these genes and its function in mammalian gonads was unknown. We therefore investigated the phenotypes of total and gonad-specific Dmxl2 knockout mouse lines. The total loss-of-function of Dmxl2 was lethal in neonates, with death occurring within 12 hours of birth. Dmxl2-knockout neonates were weak and did not feed. They also presented defects of olfactory information transmission and severe hypoglycemia, suggesting that their premature death might be due to global neuronal and/or metabolic deficiencies. Dmxl2 expression in the gonads increased after birth, during follicle formation in females and spermatogenesis in males. DMXL2 was detected in both the supporting and germinal cells of both sexes. As Dmxl2 loss-of-function was lethal, only limited investigations of the gonads of Dmxl2 KO pups were possible. They revealed no major defects at birth. The gonadal function of Dmxl2 was then assessed by conditional deletions of the gene in gonadal supporting cells, germinal cells, or both. Conditional Dmxl2 ablation in the gonads did not impair fertility in males or females. By contrast, male mice with Dmxl2 deletions, either throughout the testes or exclusively in germ cells, presented a subtle testicular phenotype during the first wave of spermatogenesis that was clearly detectable at puberty. Indeed, Dmxl2 loss-of-function throughout the testes or in germ cells only, led to sperm counts more than 60% lower than normal and defective seminiferous tubule architecture. Transcriptomic and immunohistochemichal analyses on these abnormal testes revealed a deregulation of Sertoli cell phagocytic activity related to germ cell apoptosis augmentation. In conclusion, we show that Dmxl2 exerts its principal function in the testes at the onset of puberty, although its absence does not compromise male fertility in mice., Author summary DMXL2 gene dysfunction underlies various human diseases, including breast cancer, non-syndromic hearing loss, and polyendocrine-polyneuropathy syndrome, demonstrating the large range of potential actions of DMXL2. We show here that Dmxl2 expression is crucial for survival in mice, as neonates die within hours of birth when this gene is inactivated. The transmission of olfactory information is affected, leading to an absence of suckling and impaired feeding. Severe hypoglycemia is also observed in male neonates. We observed Dmxl2 expression in several organs, including the brain, heart and adrenal glands, potentially corresponding to some of the phenotypes observed in Dmxl2-deficient pups. We also described Dmxl2 expression in the reproductive tracts and gonads and showed that Dmxl2 inactivation specifically in the testes has a significant effect on the initial waves of spermatogenesis, resulting in very low levels of sperm production at puberty. Our results suggest that DMXL2 deficits should be considered in men with impaired fertility, as pathogenic variants of this gene may be associated with male infertility in humans.

The authors want to acknowledge the Alifert Collaborative Group: Isabelle Aknin: Unité fonctionnelle de biologie de la reproduction, histologie – embryologie – cytogénétique, hôpital Nord, Saint-Étienne, France; Isabelle Cedrin-Durnerin: Service de Médecine de la Reproduction, Hôpital Jean Verdier, APHP, Bondy, France; Steven Cens, Centre d’AMP de PAU, Polyclinique de Navarre, Pau, France; Pascale Chavatte-Palmer: INRA, UMR1198 Biologie du Développement et Reproduction, Jouy en Josas, France; Serge Hercberg: EREN, INSERM U557; INRA; CNAM; Université Paris 13, CRNH IdF, 93017 Bobigny, France; Khaled Pocate: Service d’Histologie-Embryologie-Biologie de la Reproduction, Hôpital Cochin APHP, Paris, France; Nathalie Sermondade: Service de biologie de la reproduction-CECOS, Hôpital Tenon, APHP, Paris, France; Claude Uthurriague, Centre d’AMP de PAU, Polyclinique de Navarre, Pau; Jean-Philippe Wolf: Service d’Histologie-Embryologie-Biologie de la Reproduction, Hôpital Cochin, APHP, Paris, France; Overweight and obesity are known to impact male fertility and are commonly associated with abdominal obesity and metabolic disorders. The association between abdominal obesity or metabolic syndrome with male reproduction has not been fully investigated. Moreover, many factors may interfere with the evaluation of the impact of metabolic syndrome on male fertility. Thus, tobacco is known to alter the spermatic parameters and phenomena linking smoking with metabolic syndrome are therefore complex. The main objective of this study has been to investigate the potential association of metabolic syndrome with male idiopathic infertility given smoking status.The data of this study concerned infertile (n = 96) and fertile (n = 100) men under 45 years of age who have been recruited in the ALIFERT case-control study. Body mass index and waist circumference were measured. Serum triglycerides, cholesterol (total, high density lipoprotein, and low density lipoprotein cholesterol) and fasting blood glucose were assayed. Metabolic syndrome has been diagnosed in the presence of at least three of the following criteria: increased waist circumference, high triglycerides, fasting glucose or arterial blood pressure and low high density lipoprotein cholesterol.The present study reports that infertile men are in poorer health condition compared to fertile men and are more often smokers. The results of this study suggested metabolic syndrome and smoking to be independent risk factor for idiopathic infertility. Metabolic syndrome and smoking should systematically be checked at the beginning of medical care in infertile males and personal and multifaceted coaching should be proposed to deal jointly with smoking and metabolic disorders

Eighteen (18) lactating she-camels and two mature male for mating were used to determine the effect of Management System on camel calving interval, The camels were maintained under semi-intensive (N = 9) and Traditional management system (N = 9) in North Kordofan State, western Sudan. The experimental females in each group kept together with the bull during 18 months. Blood samples were collected from jugular vein since 4-months post-partum and continue 14 successive months at monthly interval. The serum samples were separated and stored at -20°C and were analysed for progesterone concentration using progesterone specific radio immuno assay (RIA) kits. The results indicated that under semi-intensive system 77.8% of females had been pregnant in 5th - 8th month post-partum and the calving interval varying between 17 to 20 months. Under traditional system and during the experimental period 44.5% of females were pregnant in the 11th – 16th month and the calving interval varying between 23 to 28 months. The ratios of pregnant vs non-pregnant during experimental period in semi-intensive and traditional were 88.9% vs 11.1% and 44.5% vs 55.5%, respectively. Beside the behavioural signs progesterone level consider a good indicator for pregnancy in camels. In pregnant females Progesterone concentration increased significantly during early months. The range of Progesterone concentration varied between 1.10 – 5.76 ng/ml and 0.67 – 2.53 ng/ml in semi-intensive and traditional system, respectively. Our results allow quantifying this impact. With a supplemented diet including 2 Kg of concentrates and 5 kg of roughages per day, the fertility rate will be improved of 67%. It would be possible to expect more than two fold young camels in a year by supplemented 5 kg of concentrates. We conclude that under semi-intensive management dietary supplement during post-partum and early lactation period improves reproductive parameters for instance shortened calving interval.

International audience; Key message Several aspects of the life cycle of the Périgord black truffle have been elucidated only recently, while others remain either controversial or unstudied. In this paper, we present a revised life cycle of this fungus and highlight key aspects that have yet to be addressed or require further understanding.• ContextThe hypogeous sporophores of several Tuber species, renowned for their aromatic and gustatory qualities, are widely commercialized. One of the most valuable species is Tuber melanosporum Vittad., the Périgord black truffle also known as “the black diamond”. However, many aspects of T. melanosporum life cycle remain unsolved.• AimsIn this work, we examine past and recent findings on the life cycle of T. melanosporum, currently regarded as a model system for Tuber species, with the view of highlighting aspects of its life cycle which remain unsolved.• ResultsSeveral aspects of its life cycle have recently been elucidated (i.e. characterization of two mating type genes, heterothallism, prevalence of sexual reproduction on vegetative propagation, exclusion of one mating type by its opposite on ectomycorrhizas, dependency of ascocarps on their host for carbon allocation), while others remain unaddressed.• ConclusionNumerous additional aspects of the T. melanosporum life cycle remain unsolved, such as exclusion or competition mechanisms between ectomycorrhizal mating types, factors involved in ascocarp initiation, the nature of the connection linking ascocarps and mycorrhizas and atmospheric nitrogen fixation.

Climate change and increasing temperature impact abundance and distribution of thousands of organisms, aquatic and terrestrial, and some ecosystems are particularly sensitive to these global changes. Increasing temperature is the principal threat for coral populations, which are ecological engineers of coral reef ecosystems. While research on coral reefs has first sought to study adult corals, data are still lacking on early life stages of corals. As sexual and asexual reproduction may play a key role in the conservation and restoration of coral reefs, my doctoral research aims to better understand changes on sexual and asexual reproduction in the face of rising temperature. The first axis of my Ph. D. was built on the response of early life stages to increasing temperature, in order to assess whether pre-exposure of early life may improve their ulterior performance. Among the different experiments performed on the genus Acropora, I highlighted 1) a high thermal tolerance (+2-3°C above ambient temperature) of gametes, 2) a higher sensibility of oocytes than sperm to rising temperature exposure, and 3) the pivotal role of gamete thermal history on fertilization output. Finally, I identified optimal pre-exposure conditions in order to maximize fertilization success. While an increasing interest in sexual reproduction was observed these last years, asexual reproduction and fragmentation still remain the main tool to restore damaged reefs. Thus, in the second axis of my doctoral project, I investigated the phenotypic plasticity of corals by growing 3 different species of corals across 3 different environments. Their growth rates, health status and survival probability were determined. Results from this axis showed that differences were observed at the interspecific and intraspecific levels. This work revealed that a selection based on phenotypic plasticity among different life-traits (growth rates and health status) and different environments should allow to increase coral reef restoration strategies. Hence the selection of individuals (asexual reproduction) in a species based on coral common garden experiment allow to identify individuals of interest to use as restoration biological materials. Additionally, thermal pre-conditioning of early life stages (sexual reproduction) is another way to increase efficiency of restoration measures in the face of rising temperature. My doctoral research provided new information regarding physiological and biological processes of scleractinian corals facing environmental changes and proposed new solutions for restorations based on sexual and/or asexual reproduction.; Le changement climatique et l’augmentation des températures globales perturbent l’abondance et la distribution de milliers d’organismes, aquatiques et terrestres, et certains écosystèmes sont particulièrement sensibles à ces changements environnementaux. L’augmentation de température est la principale menace au maintien des populations de coraux, véritables ingénieurs écologiques de ces écosystèmes. Bien que la recherche sur les récifs coralliens se soit d’abord attachée à l’étude des coraux adultes, de nombreuses informations manquent sur la reproduction sexuée et asexuée, et leur rôle dans la conservation et restauration récifale. Le premier axe de ma thèse s’est donc construit sur la réponse des jeunes stades de vie à l’augmentation de température, pour d’abord évaluer les modifications de leur performance et ensuite évaluer dans quelles mesures les jeunes stades seraient capables de s’acclimater à des conditions de températures plus élevées. Au travers de différentes expérimentations en laboratoire sur le genre Acropora, j’ai ainsi mis en évidence 1) une résistance thermique importante (+2-3°C au-dessus des températures ambiantes) des gamètes face à l’augmentation de température, 2) une résistance thermique différente entre spermatozoïdes et ovocytes: ovocytes < spermatozoïdes, 3) et la mise en évidence du rôle majeur de l’environnement dans lequel se rencontre les gamètes une fois libérés, sur la qualité et la quantité de la fécondation. Enfin, j’ai identifié les conditions optimales thermiques de pré-exposition des gamètes pour maximiser leur succès de fécondation. Bien qu’un intérêt croissant soit porté sur la reproduction sexuée ces dernières années, l’utilisation de la reproduction asexuée demeure la méthode la plus utilisée pour restaurer les récifs coralliens, plus connue sous le nom de bouturage. Ainsi le second axe de ma thèse a cherché à mettre en évidence la plasticité phénotypique des coraux en cultivant des boutures provenant de 3 espèces dans 3 environnements différents et en analysant leur taux de croissance, leur état de santé et leur survie. Cet axe a pu montrer qu’il existait des différences à plusieurs échelles, entre espèces, mais aussi au sein d’une même espèce. Mes travaux montrent qu’une sélection des individus basée sur l’étude de la plasticité phénotypique de certains traits d’histoires de vie comme la croissance ou l’état de santé dans des environnements variables permettrait d’améliorer l’efficacité de la restauration récifale. Ainsi le choix des individus au sein d’une même espèce afin de réaliser du bouturage (reproduction asexuée) et le conditionnement de la phase de vie gamètes (reproduction sexuée) peut permettre d’augmenter l’efficacité des méthodes de restaurations tout en nous donnant des informations nouvelles sur la biologie et la physiologie des coraux scléractiniaires face aux changements environnementaux.

Climate change and increasing temperature impact abundance and distribution of thousands of organisms, aquatic and terrestrial, and some ecosystems are particularly sensitive to these global changes. Increasing temperature is the principal threat for coral populations, which are ecological engineers of coral reef ecosystems. While research on coral reefs has first sought to study adult corals, data are still lacking on early life stages of corals. As sexual and asexual reproduction may play a key role in the conservation and restoration of coral reefs, my doctoral research aims to better understand changes on sexual and asexual reproduction in the face of rising temperature. The first axis of my Ph. D. was built on the response of early life stages to increasing temperature, in order to assess whether pre-exposure of early life may improve their ulterior performance. Among the different experiments performed on the genus Acropora, I highlighted 1) a high thermal tolerance (+2-3°C above ambient temperature) of gametes, 2) a higher sensibility of oocytes than sperm to rising temperature exposure, and 3) the pivotal role of gamete thermal history on fertilization output. Finally, I identified optimal pre-exposure conditions in order to maximize fertilization success. While an increasing interest in sexual reproduction was observed these last years, asexual reproduction and fragmentation still remain the main tool to restore damaged reefs. Thus, in the second axis of my doctoral project, I investigated the phenotypic plasticity of corals by growing 3 different species of corals across 3 different environments. Their growth rates, health status and survival probability were determined. Results from this axis showed that differences were observed at the interspecific and intraspecific levels. This work revealed that a selection based on phenotypic plasticity among different life-traits (growth rates and health status) and different environments should allow to increase coral reef restoration strategies. Hence the selection of individuals (asexual reproduction) in a species based on coral common garden experiment allow to identify individuals of interest to use as restoration biological materials. Additionally, thermal pre-conditioning of early life stages (sexual reproduction) is another way to increase efficiency of restoration measures in the face of rising temperature. My doctoral research provided new information regarding physiological and biological processes of scleractinian corals facing environmental changes and proposed new solutions for restorations based on sexual and/or asexual reproduction.; Le changement climatique et l’augmentation des températures globales perturbent l’abondance et la distribution de milliers d’organismes, aquatiques et terrestres, et certains écosystèmes sont particulièrement sensibles à ces changements environnementaux. L’augmentation de température est la principale menace au maintien des populations de coraux, véritables ingénieurs écologiques de ces écosystèmes. Bien que la recherche sur les récifs coralliens se soit d’abord attachée à l’étude des coraux adultes, de nombreuses informations manquent sur la reproduction sexuée et asexuée, et leur rôle dans la conservation et restauration récifale. Le premier axe de ma thèse s’est donc construit sur la réponse des jeunes stades de vie à l’augmentation de température, pour d’abord évaluer les modifications de leur performance et ensuite évaluer dans quelles mesures les jeunes stades seraient capables de s’acclimater à des conditions de températures plus élevées. Au travers de différentes expérimentations en laboratoire sur le genre Acropora, j’ai ainsi mis en évidence 1) une résistance thermique importante (+2-3°C au-dessus des températures ambiantes) des gamètes face à l’augmentation de température, 2) une résistance thermique différente entre spermatozoïdes et ovocytes: ovocytes < spermatozoïdes, 3) et la mise en évidence du rôle majeur de l’environnement dans lequel se rencontre les gamètes une fois libérés, sur la qualité et la quantité de la fécondation. Enfin, j’ai identifié les conditions optimales thermiques de pré-exposition des gamètes pour maximiser leur succès de fécondation. Bien qu’un intérêt croissant soit porté sur la reproduction sexuée ces dernières années, l’utilisation de la reproduction asexuée demeure la méthode la plus utilisée pour restaurer les récifs coralliens, plus connue sous le nom de bouturage. Ainsi le second axe de ma thèse a cherché à mettre en évidence la plasticité phénotypique des coraux en cultivant des boutures provenant de 3 espèces dans 3 environnements différents et en analysant leur taux de croissance, leur état de santé et leur survie. Cet axe a pu montrer qu’il existait des différences à plusieurs échelles, entre espèces, mais aussi au sein d’une même espèce. Mes travaux montrent qu’une sélection des individus basée sur l’étude de la plasticité phénotypique de certains traits d’histoires de vie comme la croissance ou l’état de santé dans des environnements variables permettrait d’améliorer l’efficacité de la restauration récifale. Ainsi le choix des individus au sein d’une même espèce afin de réaliser du bouturage (reproduction asexuée) et le conditionnement de la phase de vie gamètes (reproduction sexuée) peut permettre d’augmenter l’efficacité des méthodes de restaurations tout en nous donnant des informations nouvelles sur la biologie et la physiologie des coraux scléractiniaires face aux changements environnementaux.

Genetic engineering of Trichoderma reesei is one of the solutions considered to reduce the cost of the enzymatic hydrolysis step in second-generation ethanol production processes. It allows the improvement of the secretory performances of this cellulase producer fungus and the properties of its enzymes. Like many industrial fungi, T. reesei has long been considered to possess exclusively an asexual cycle. The recent discovery of a sexual reproduction cycle in this filamentous fungus opens up new prospects of improvement for strains used in biotechnology. However, all industrial strains of T. reesei are derived from the wild isolate QM6a and therefore possess the MAT1-2 mating type and are female sterile.The aim of this work was to develop sexual reproduction as a genetic tool and to improve the performance of the industrial strains. In combination with the genetic engineering tools, it would enable combination of interesting traits or generation of new ones, improve strains stability by purging deleterious mutations, selection markers elimination and identification of genes and mutations responsible of interesting characteristics.The first part of this work was dedicated to the optimization of sexual reproduction and to the study of the steps and mechanisms of sexual reproduction between wild-type and hyperproducer strains. In a second step, we set up sexual reproduction between female sterile hyperproducer strains, using the original "assistant strain" strategy, which resulted in the partial restoration of their sexual reproduction. A study of the fertilization step was also initiated, as we suspect it to be the blocking point in our strategy. In a second part, we took advantage of sexual reproduction between wild-type and hyperproducer strains for (i) the generation of a MAT1-1 mating-type strain compatible with all industrial strains, female fertile and possessing improved β-glucosidase activity and (ii) the implementation of a bulk segregation analysis associated with high-throughput sequencing techniques to identify mutations involved in phenotypes of interest.; Dans le cadre de la production de bioéthanol de deuxième génération, l’ingénierie génétique de Trichoderma reesei est une des solutions envisagées pour diminuer le coût de l’étape d’hydrolyse enzymatique. Elle permet d’améliorer les performances de sécrétion de ce champignon filamenteux producteur de cellulases et les propriétés de ces enzymes. Comme de nombreux champignons industriels, T. reesei a longtemps été considéré comme possédant exclusivement un cycle asexuel. La mise en évidence récente d’un cycle de reproduction sexuée chez ce champignon filamenteux ouvre de nouvelles perspectives d’amélioration des souches utilisées en biotechnologie. Cependant, comme toutes les souches industrielles de T. reesei dérivent de l’isolat sauvage QM6a, elles sont toutes de type sexuel MAT1-2 et stériles en tant que femelles. L’objectif de ce travail de thèse est de mettre en place la reproduction sexuée comme outil génétique et d’amélioration des performances des souches industrielles. Son utilisation en complément des outils d’ingénierie génétique permet de combiner des caractères intéressants ou d’en générer de nouveaux, de stabiliser les souches industrielles en éliminant les mutations non désirées, de s’affranchir des marqueurs de sélection et d’identifier les gènes et mutations responsables d’un caractère d’intérêt. La première partie de ce travail a été consacré à l’optimisation de la reproduction sexuée puis à l’étude des étapes et des mécanismes de la reproduction sexuée entre souches sauvages et hyperproductrices. Dans un deuxième temps, nous avons mis en place la reproduction sexuée entre des souches hyperproductrices femelles stériles, à l’aide de la stratégie originale de la « souche assistante », qui a abouti au rétablissement partiel de leur reproduction sexuée. Afin de compléter ce rétablissement, une étude de l’étape de fécondation que nous supposons être l’étape problématique dans notre stratégie a été initiée. Parallèlement, l’exploitation de la reproduction sexuée entre souches sauvage et hyperproductrices a permis de générer une souche hyperproductrice de cellulases, de type sexuel MAT1-1 donc compatible avec toutes les souches industrielles, femelle fertile et possédant une activité β-glucosidase améliorée. Enfin, la reproduction sexuée associée à la génétique classique (« Bulk Segregant Analysis ») et aux techniques de séquençage haut débit a été mise en oeuvre pour permettre l’identification de mutations impliquées dans des phénotypes d’intérêt.

Modifications ciblées du génome des animaux de rentes : comment et pourquoi ? . Colloque ARET 2017 "Les OGM : Des risques et des enjeux?"

Les invasions biologiques sont considérées actuellement par la communauté scientifique comme des vecteurs de modification de la biodiversité et de changement des écosystèmes. La rapide invasion de la sous-espèce exotique du roseau commun (Phragmites australis) dans le nord-est de l'Amérique du Nord est un exemple spectaculaire d'envahissement végétal. Un programme de prévention et de contrôle de cette herbacée nécessite une connaissance adéquate de la biologie, de la génétique et de l'écologie de cette plante envahissante. Le but général de ma thèse de doctorat est d'améliorer le savoir sur la dynamique de dispersion du roseau commun envahisseur au Québec, en étudiant ses caractéristiques de reproduction biologique, de diversité génétique et de tolérance écologique qui favorisent son succès d'établissement au cours de la phase de propagation. Le premier objectif est de déterminer la contribution relative des modes de reproduction sexuée et asexuée dans la dispersion à courte et longue distance, en utilisant des observations de terrain de nouveaux individus et des analyses de génétique des populations établies. Le deuxième objectif est de décrire la diversité génétique des populations par le biais de milliers de marqueurs nucléotidiques, en utilisant une meilleure résolution des génotypes et distinction des clones grâce à une nouvelle technologie de dernière génération, le génotypage-par-séquençage. Le troisième objectif est d'identifier le niveau de tolérance écologique du roseau et les facteurs environnementaux hostiles à sa prolifération, en utilisant des régressions logistiques binaires basées sur des données biotiques et abiotiques de sites envahis et non envahis par l'espèce. Le premier volet confirme que le roseau s'établit majoritairement par graines sur de vastes territoires, et se propage latéralement par rhizomes et stolons à l'échelle locale. La fondation de nouvelles populations le long des routes est également assurée par la dissémination de fragments végétatifs. Le deuxième volet confirme que le roseau dispose d'une forte recombinaison génétique par reproduction sexuée qui lui permet d'acquérir un potentiel évolutif et une adaptation rapide. La nouvelle approche de génotypage permet de réduire les imprécisions liées à l'utilisation d'un petit nombre de marqueurs microsatellites. Le troisième volet confirme que le roseau colonise des fossés de drainage ouverts exposés au soleil et dénués de végétation arborée. Cette espèce ne tolère pas la présence de ligneux et l'absence de lumière. En somme, cette thèse présente un portrait biologique, génétique et écologique des caractéristiques du roseau envahisseur qui influencent sa propagation au Québec. Ces résultats justifient l'ensemencement d'herbacées indigènes et la plantation de haies arbustives pour restaurer les écosystèmes perturbés afin de prévenir l'existence de lits de germination propices à l'établissement par graines du roseau. Cependant, la gestion du roseau commun envahisseur dépend du contexte, puisque cette plante peut également rendre bon nombre de services écologiques., Biological invasions are currently considered by the scientific community drivers of biodiversity and ecosystem change. The rapid invasion of the exotic subspecies of common reed (Phragmites australis) in the northeast of North America is a spectacular example of plant invasion. A prevention and control program of this grass requires adequate knowledge of biology, genetics and ecology of this invasive plant. The overall aim of my thesis is to improve knowledge on the dynamics of dispersal of the invasive common reed in Quebec, by studying its characteristics of biological reproduction, genetic diversity and ecological tolerance that promote its establishment success during the spread stage. The first objective is to determine the relative contribution of sexual and asexual reproduction modes in the short and long distance dispersal, using field observations of new individuals and genetic analysis of established populations. The second objective is to describe the genetic diversity of populations through thousands of nucleotide markers, using higher resolution of genotypes and distinction of clones through a novel next-generation technology, the genotyping-by-sequencing. The third objective is to identify the level of ecological tolerance of common reed and the adverse environmental conditions to its proliferation, using binary logistic regression models based on biotic and abiotic data collected in invaded and non-invaded sites by the species. The first project confirms that common reed mainly establishes by seeds over large areas, and laterally expands by rhizomes and stolons at the local scale. New populations are also founded along roads by the dispersal of vegetative fragments. The second project confirms that common reed has a high genetic recombination by sexual reproduction that allows to gain an evolutionary potential and rapid adaptation. The new genotyping approach reduces uncertainties associated with the use of a limited number of microsatellite markers. The third project confirms that common reed colonizes open drainage ditches exposed to sunlight and free of trees. This species does not tolerate the presence of wood and the absence of light. In summary, this thesis presents a biological, genetic and ecological portrait of the characteristics of the invasive common reed that influence its spread in Quebec. These results support the seeding of native herbaceous and the planting of shrub hedges to restore disturbed ecosystems in order to prevent the existence of seedbeds suitable for the establishment of the common reed by seeds. However, the management of invasive common reed depends on the context, since this plant can also provide many ecological services.

We consider organisms that mix sexual and asexual reproduction, in a situation where sexual reproduction involves both spatial dispersion and mate finding limitation. We propose a model that involves two coupled equations, the first one being an ordinary differential equation of logistic type, the second one being a reaction diffusion equation. According to realistic values of the various coefficients, the second equation turns out to involve a fast time scale, while the first one involves a separated slow time scale. First we show existence and uniqueness of solutions to the original system. Second, in the limit where the fast time scale is considered infinitely fast, we show the convergence towards a reduced quasi steady state dynamics, whose correctors can be computed at any order. Third, using monotonicity properties of our cooperative system, we show the existence of traveling wave solutions in a particular region of the parameter space (monostable case)., On considère des organismes qui mixent reproduction sexuée et asexuée, dans une situation où la reproduction sexuée fait intervenir à la fois de la dispersion spatiale et de la limitation d'appariement. Nous proposons un modèle qui implique deux équations couplées, la première étant une équation différentielle ordinaire de type logistique, la seconde étant une équation de réaction-diffusion. Grâce à des valeurs réalistes des différents coefficients, il s'avère que la deuxième équation fait intervenir une échelle de temps rapide, alors que la première fait intervenir une échelle de temps lente. Dans un premier temps, on montre l'existence et l'unicité de solutions au système original. Dans un second temps, dans la limite où l'échelle de temps rapide est considérée infiniment rapide, on montre la convergence vers une dynamique réduite d'état d'équilibre, dont les termes correctifs peuvent être calculés à tout ordre. Troisièmement, en utilisant des propriétés de monotonie de notre système coopératif, on montre l'existence d'ondes progressives dans une région particulière de l'espace des paramètres (cas monostable).

La truffe révèle les secrets de sa sexualité

Truffe en quête de pères : un champignon à l’orientation sexuelle forcée, et pas encore domestiqué !

International audience; In a context of the global major changes, it is mandatory to enlarge the range of crops supporting food security and pay great attention to neglected and underutilized species. However, basic knowledge of the biology of many neglected and underutilized species is still lacking to increase their yields. In this study, the mating system of white fonio [Digitaria exilis (Kippist.) Stapf], a West African minor and promising cereal, is assessed. Progenies arrays from both homozygous and heterozygous mothers were genotyped with microsatellites markers. The rate of genotyping errors in the experiments was assessed and a likelihood framework was used to determine the probability of different mating systems: outcrossing, self-fertilization and apomixis. The results suggested that white fonio has a highly selfing reproductive system with a possible outcrossing rate of 1.7%. Understanding the reproduction system of white fonio opens up opportunities for more effective breeding programs and a wider use of this cereal for food security improvement.

Fruit ripening is divided into climacteric and non-climacteric types depending on the presence or absence of a transient rise in respiration rate and the production of autocatalytic ethylene. Melon is ideal for the study of fruit ripening, as both climacteric and non-climacteric varieties exist. Two introgressions of the non-climacteric accession PI 161375, encompassed in the QTLs ETHQB3.5 and ETHQV6.3, into the non-climacteric ‘Piel de Sapo’ background are able to induce climacteric ripening independently. We report that the gene underlying ETHQV6.3 is MELO3C016540 (CmNAC-NOR), encoding a NAC (NAM, ATAF1,2, CUC2) transcription factor that is closely related to the tomato NOR (non-ripening) gene. CmNAC-NOR was functionally validated through the identification of two TILLING lines carrying non-synonymous mutations in the conserved NAC domain region. In an otherwise highly climacteric genetic background, both mutations provoked a significant delay in the onset of fruit ripening and in the biosynthesis of ethylene. The PI 161375 allele of ETHQV6.3 is similar to that of climacteric lines of the cantalupensis type and, when introgressed into the non-climacteric ‘Piel de Sapo’, partially restores its climacteric ripening capacity. CmNAC-NOR is expressed in fruit flesh of both climacteric and non-climacteric lines, suggesting that the causal mutation may not be acting at the transcriptional level. The use of a comparative genetic approach in a species with both climacteric and non-climacteric ripening is a powerful strategy to dissect the complex mechanisms regulating the onset of fruit ripening., This work was supported by the Spanish Ministry of Economy and Competitivity grant AGL2015-64625-C2-1-R, Centro de Excelencia Severo Ochoa 2016-2020, and the CERCA Programme/Generalitat de Catalunya to JGM; Spanish Ministry of Economy and Competitivity/FEDER grant AGL2015-64625-C2-2-R to AJM; EU Framework Program Horizon 2020 COST Action FA1106 Quality Fruit for networking activities to CL; European Research Council grant ERC-SEXYPARTH to AB; Chief Scientist of the Ministry of Agriculture of Israel grant no. 261-1049-13 to NK.

Background Porcine reproductive and respiratory syndrome virus (PRRSV) is responsible for reproductive disorders in sows and respiratory problems in pigs, and has a major economic impact. Controlling PRRSV is therefore a priority for the swine industry. Stabilization of a herd, defined as the production of PRRSV-negative pigs at weaning from seropositive sows, is a common method of control, and different protocols have been described in the literature to achieve this stabilization. Context and purpose The objective of this study was to evaluate wether the combination of mass vaccination of sows and their piglets with a Genotype I modified live virus (MLV) vaccine, with temporal closure to the introduction of replacement animals and unidirectional pig and human flow can result in the production of PRRSV-negative pigs at weaning. The study took place in French farrow-to-finish farms located in a high-density swine area where the disease concerns over 60% of farms and only closely related strains of genotype I have been reported. Twenty-three 100-to-700 sow farrow-to-finish farms were selected prospectively between 2005 and 2014, regardless of their biosecurity level. Those farms adopted a stabilization protocol characterized by the following standardized measures: vaccination of sows, gilts, and piglets with the Genotype I MLV vaccine PORCILIS®PRRS, temporary herd closure, and strict internal biosecurity measures. Monitoring of herd status was then performed using a combination of 3 diagnostic tools: Real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and Open reading frame (ORF) 5 and ORF7 sequencing. The status of finishing units (either active or inactive, meaning PRRSV-positive or PRRSV-negative, respectively) was not considered in this study. Results and conclusions At the end of the monitoring period, considering the results of all the analyses, clinical signs, and epidemiology, 19 farms were considered stable and 1 remained unstable. In 3 farms it was commonly agreed to extend the number of vaccinated batches of piglets, which enabled them to be considered stable at the end of a second round of monitoring. The combination of vaccination of sows and their piglets with a Genotype I MLV vaccine, together with the closure of the farm and a unidirectional pig and human flow, seems to be effective for farrow–to-finish farms even in high-density swine area, even with French PRRSV strains closely related to one another. This research is the first European study examining such a large number of farms, and increased confidence in the results stems from the added value of using the ORF7 and ORF5 sequencing tool.

Tychoparthenogenesis, a form of asexual reproduction in which a small proportion of unfertilized eggs can hatch spontaneously, could be an intermediate evolutionary link in the transition from sexual to parthenogenetic reproduction. The lower fitness of tychoparthenogenetic offspring could be due to either developmental constraints or to inbreeding depression in more homozygous individuals. We tested the hypothesis that in populations where inbreeding depression has been purged, tychoparthenogenesis may be less costly. To assess this hypothesis, we compared the impact of inbreeding and parthenogenetic treatments on eight life‐history traits (five measuring inbreeding depression and three measuring inbreeding avoidance) in four laboratory populations of the desert locust, Schistocerca gregaria, with contrasted demographic histories. Overall, we found no clear relationship between the population history (illustrated by the levels of genetic diversity or inbreeding) and inbreeding depression, or between inbreeding depression and parthenogenetic capacity. First, there was a general lack of inbreeding depression in every population, except in two populations for two traits. This pattern could not be explained by the purging of inbreeding load in the studied populations. Second, we observed large differences between populations in their capacity to reproduce through tychoparthenogenesis. Only the oldest laboratory population successfully produced parthenogenetic offspring. However, the level of inbreeding depression did not explain the differences in parthenogenetic success between all studied populations. Differences in development constraints may arise driven by random and selective processes between populations.

International audience; Fungal plant parasites represent a growing concern for biodiversity and food security. Most ascomycete species are capable of producing different types of infectious spores both asexually and sexually. Yet the contributions of both types of spores to epidemiological dynamics have still to been fully researched. Here we studied the effect of mate limitation in parasites which perform both sexual and asexual reproduction in the same host. Since mate limitation implies positive density dependence at low population density, we modeled the dynamics of such species with both density-dependent (sexual) and density-independent (asexual) transmission rates. A first simple SIR model incorporating these two types of transmission from the infected compartment, suggested that combining sexual and asexual spore production can generate persistently cyclic epidemics in a significant part of the parameter space. It was then confirmed that cyclic persistence could occur in realistic situations by pa-rameterizing a more detailed model fitting the biology of the Black Sigatoka disease of banana, for which literature data is available. We discuss the implications of these results for research on and management of Sigatoka diseases of banana.

To compare the effect of melatonin-based to progestagens with equine chorionic gonadotropin (eCG) based treatments used to improve the reproductive performance of Ouled-Djellal sheep breed, 829 ewes distributed among four farms (A, B, C, and D; n = 248, 351, 100, and 80; respectively) were monitored from March to October 2008. In farm B, progestagens improved fertility by 92.3% in ewes treated with medroxy- progesterone acetate (MAP) + eCG 400 IU, and by 84.1% in ewes treated with fluorogestone acetate (FGA) + eCG 500 IU, compared to 23.2% in the control group. The fertility rates obtained with melatonin implants after first mating in farms A and C were significantly lower than those obtained with progestagens + eCG (A: 40.9 vs 79.9%; C: 24 vs 70%). The fertility rate obtained with melatonin implants after first mating in farm A was higher (40.9%) than those obtained in farms C (24%) and D (17.5%). In farm D, melatonin implants improved total fertility compared to control (55.0 vs 17.5%, respectively). MAP + eCG 400 IU improved the conception rate at first mating in farms A (1.30) and B (1.70), whereas FGA + eCG 500 IU, and melatonin implants did not. Melatonin implants, in combination with the ram effect, and used at an early stage yielded good results that were similar to those obtained with progestagens.

BGPI : équipe 5; International audience; Inferring invasion routes and identifying reservoirs of diversity of plant pathogens are essential in proposing new strategies for their control. Magnaporthe oryzae, the fungus responsible for rice blast disease, has invaded all rice growing areas. Virulent genotypes regularly (re) emerge, causing rapid resistance breakdowns. However, the world-wide genetic subdivision of M. oryzae populations on rice and its past history of invasion have never been elucidated. In order to investigate the centers of diversity, origin and migration of M. oryzae on rice, we analyzed the genetic diversity of 55 populations from 15 countries. Three genetic clusters were identified world-wide. Asia was the center of diversity and the origin of most migrations to other continents. In Asia, two centers of diversity were revealed in the Himalayan foothills: South China–Laos–North Thailand, and western Nepal. Sexual reproduction persisted only in the South China–Laos–North Thailand region, which was identified as the putative center of origin of all M. oryzae populations on rice. Our results suggest a scenario of early evolution of M. oryzae on rice that matches the past history of rice domestication. This study confirms that crop domestication may have considerable influence on the pestification process of natural enemies.

International audience; In Vanilla species (Orchidaceae), the influence of sexual and asexual mating systems on the spatial structuring of population genetic diversity is understudied. These elements are crucial in restoration program to limit inbreeding depression and to maintain the genetic diversity of natural populations. In the remnant fragments of tropical dry forest in Mayotte (Comoros Archipelago, Indian Ocean), the clarification of the reproductive strategies of the orphan leafless Vanilla humblotii Rchb. f. will provide a better understanding of its fine-scale spatial genetic structure. Approaches combining reproductive biology and fine-scale spatial genetic structure analyses using ten mi-crosatellite markers in 49 individuals sampled in the only remaining large population of V. humblotii were employed to unravel the reproductive strategies of this species. The results showed that V. humblotii displays un-scented flowers and is allogamous and pollinator-dependent although also self-compatible. A total absence of pollen movements and a low level of natural fruit set (~1%) are reported, although a wild bee (Allodape obscuripennis Strand, Xylocopinae) and a bird (Nectarinia coquerelli,Nectarinidae) visitedthe flowers. A high ge-notypic diversity (G/N = 0.88) and a phalanx clonal growth are detected, and seed dispersal is higher than pollen dispersal. The phalanx distribution of the repeated genotypes (ramets arisen from the same genet) is responsible for significant autocorrelations detected at small distances. Limited inbreeding was detected although geitonogamy could have been enhanced by vegetative reproduction. This study highlights the need to perform interdisciplinary studies to unravel the reproductive strategy of clonal plant species with a deceptive pollination system.

The contribution of crop debris as inoculum source of many plant pathogens has been recognized for decades. Two important pathogens in the classical wheat-oilseed rape rotation are Zymoseptoria tritici (septoria leaf blotch of wheat) and Leptosphaeria maculans (stem canker of oilseed rape). Both fungi initiate their sexual stages on plant debris during the intercropping period, which results in ascospore release for subsequent epidemics. Despite the importance of debris in disease outbreak, few information is known about the structure and function of microbial communities associated to this plant habitat. The objective of this work is to characterize bacterial and fungal assemblages associated to wheat and oilseed rape debris and to assess their relative impacts on the build-up of primary inoculum during theintercropping period. The challenge is to identify competitive interactions between pathogens and debris-associated micro-organisms in order to use these latter as potential biocontrol agents. The study is based on a field design composed of three plots (wheat monoculture, oilseed rape-wheat rotations) established in the experimental domain of Grignon (Paris basin). Wheat and oilseed rape crop debris are sampled thrice a year during the ascospore release period. The structure of debris-associated microbial assemblages is assessed through a combination of classical microbiological approaches and sequencing of two molecular markers (16S rRNA gene and ITS1 region of the fungal internal transcribed spacer). Both approaches will assess the impact of crop sequence on microbial assemblages and should ultimately lead to the identification of micro-organisms exhibiting antagonistic activities towards either Z. tritici or L. maculans. To this end, the impact of different microbial assemblages and isolated species on the ascospore production from wheat debris infected by Z. tritici will be tested in field and controlled condition experiments.

International audience; This special topic issue of Sexual Development gives an overview of sex reversal in vertebrates, from fishes naturally changing their sex, to rodents escaping the mammalian SRY-determining system. It offers eight up-to-date reviews on specific subjects in sex reversal, considering fishes, amphibians, reptiles, birds, marsupials, and placental mammals, including humans. The broad scope of represented animals makes this ideal for students and researchers, especially those interested in the evolution of sex-determination mechanism, as they seek to update their knowledge of sex differentiation in vertebrates.

Sexual compatibility limits the production of cacao plantations, being an important selection criterion in breeding programs. However, the current method for characterizing compatibility, based on the frequency of flower setting after controlled pollination, is time consuming, requiring a long time to identify self-compatible individuals. The identification of molecular markers in genomic regions can be an alternative to allow early selection of self-compatible plants. The present study aimed to identify SNP markers associated with sexual compatibility in cacao, by utilizing genome-wide association (GWAS) mapping. A population of 295 individuals mostly from third-generation breeding populations, but also founder clones, was used. This population was phenotypically characterized by hand pollinating 8199 flowers and evaluating the flower retention 15 days after pollination. In addition, leaf samples of each individual were collected and DNA extracted for genotyping by sequencing, generating 5301 SNP markers after cleaning. Genome-wide association mapping analysis was performed using Synbreed, GCTA, and TASSEL softwares. Significant markers associated to incompatibility, likely in strong linkage disequilibrium, were found within a region of 196 kb, in the proximal end of chromosome 4, suggesting the existence of a major gene in that region. However, this result should be validated in a larger population, considering that only 295 trees were used here. When the SNP effects were treated as random in the estimation process, many other regions in the genome appears to be involved with sexual incompatibility in cacao. Candidate genes were found not only in the proximal end of chromosome 4 but also spread in several other regions of the genome.

While porcine reproductive and respiratory syndrome (PRRS) causes great economic losses in southern and central China, systematic studies on the epidemiology of PRRS virus (PRRSV) in Heilongjiang Province had not been performed. Therefore, we conducted a preliminary study to estimate the prevalence and risk factors associated with PRRSV infection, as well as characterize the PRRSV in registered pig farms in Heilongjiang Province, China in 2011. A total of 1237 blood samples were collected from 72 farms and tested by reverse transcription polymerase chain reaction (RT-PCR) for PRRSV. Risk factors associated to PRRSV infection were analysed using logistic regression models. Genes of non-structural protein-2 (Nsp2) and glycoprotein 5 (GP5) from 22 isolates were sequenced for phylogenetic analysis. The results showed that the herd apparent prevalence was 9.7% (95% CI: 6.3, 13.1) in Heilongjiang Province. An increased risk of PRRSV infection on farms was associated with unrestricted movement of external people (OR = 14.1, 95% CI: 1.68, 119.07), close proximity (

Les anomalies congénitales sont définies comme des défauts de structure ou de fonction présents à la naissance. Bien que la fréquence des anomalies congénitales soit relativement faible, leur impact en production porcine est significatif. Elles provoquent le plus souvent un mal-être des animaux et une dépréciation des carcasses à l’abattoir induisant des pertes économiques. Les anomalies congénitales peuvent être de nature diverse, mais les défauts les plus courants rencontrés chez le porcelet sont de type urogénital (les hernies inguinales et scrotales, la cryptorchidie et l’intersexualité). Ces défauts peuvent être dus à des problèmes nutritionnels, aux conditions d’environnement ou à la conduite de l’élevage, mais une part de leur déterminisme est très souvent génétique. Les développements récents des outils de génomique permettent désormais d’entreprendre, à grande échelle, des études d’association afin d’identifier les régions chromosomiques des gènes impliqués. L’identification des mutations causales est devenue une priorité afin de proposer de nouveaux schémas de sélection. L’objectif de cet article est de présenter une synthèse des connaissances génétiques sur les anomalies congénitales les plus fréquentes chez le porc et les stratégies mises en œuvre pour gérer ces défauts en sélection., Congenital diseases are defined as physical or functional defects, which are present at birth. Although the incidence of congenital disorders is quite low, it is a significant problem in the pig industry. These defects have a serious impact on animal welfare and induce economic losses due to carcass depreciation. Congenital diseases are various but the most common defects occurring in piglets are urogenital diseases (scrotal or inguinal hernias, cryptorchidism, and intersexuality). Defects can arise from nutritional, environmental, management causes, as well as hereditary. Recently the developed genomics tools enable large scale, genome wide association studies to identify chromosomal regions containing causal genes. Identification of causal mutations became a priority to propose new selection schemes. The aim of this article is to present an overview of genetic knowledge on the most frequent congenital diseases in pigs, and the strategies implemented to manage these defects in selection.