Late-acting self-incompatible system, preferential allogamy and delayed selfing in the heteromorphic invasive populations of <i>Ludwigia grandiflora subsp. hexapetala</i>

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Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Reproductive system, polyploidy and genetic diversity of Ludwigia grandiflora subsp hexapetala invasive populations in France

Dans un contexte de succès de colonisation des espèces invasives, la compréhension d’un front d’invasion est essentielle afin d’identifier des leviers de gestion. En France, Ludwigia grandiflora subsp hexapetala a envahi la plupart de réseaux hydrographiques avec des populations fertiles et stériles. Les objectifs de cette thèse étaient l’identification des facteurs influençant sa reproduction sexuée et la caractérisation de sa diversité génétique afin d’inférer le mode de reproduction efficace et de comprendre l’histoire du front d’invasion. La biologie florale et la fructification des populations fertiles et stériles dans différentes conditions climatiques et après différents croisements contrôlés ainsi que la diversité génétique des populations via un set de marqueurs moléculaires SNP ont été évaluées,Ces travaux ont montré que la reproduction sexuée de Ludwigia grandiflora subsp hexapetala est sous contrôle d’un système d’auto-incompatibilité hétéromorphique « à action tardive » de type distyle-homostyle. Nous avons identifié deux fronts d’invasion avec deux points de rencontre. Le système de reproduction efficace majoritaire est la clonalité avec un signal d’allogamie au niveau des 2 « hot-spot » de diversité, suggérant une priorisation de gestion à leurs niveaux. Ces études pourront être étendues à d’autres fronts d’invasion en Europe et aux USA.In a context of successful colonization of invasive species, understanding of an invasion front is essential in order to identify management levers. In France, Ludwigia grandiflora subsp hexapetala has invaded most river systems with fertile and sterile populations. The objectives of this thesis were the identification of factors influencing its sexual reproduction and the characterisation of its genetic diversity in order to infer the efficient mode of reproduction and to understand the history of the invasion front.Floral biology and fructification of fertile and sterile populations in different climatic conditions and after different controlled crosses as well as the genetic diversity of the populations via a set of SNP molecular markers were evaluated. These studied showed that the sexual reproduction of Ludwigia grandiflora subsp hexapetala is under the control of a "late-acting" heteromorphic self-incompatibility system of the distyle-homostyle type. We have identified two invasion fronts with two meeting points. The majority efficient breeding system is clonality with an allogamy signal at the level of the 2 diversity hot spots, suggesting management prioritization at their levels. These studies could be extended to other invasion fronts in Europe and the USA

Système de reproduction, polyploïdie et diversité génétique des populations invasives de Ludwigia grandiflora subsp hexapetala en France

In a context of successful colonization of invasive species, understanding of an invasion front is essential in order to identify management levers. In France, Ludwigia grandiflora subsp hexapetala has invaded most river systems with fertile and sterile populations. The objectives of this thesis were the identification of factors influencing its sexual reproduction and the characterisation of its genetic diversity in order to infer the efficient mode of reproduction and to understand the history of the invasion front.Floral biology and fructification of fertile and sterile populations in different climatic conditions and after different controlled crosses as well as the genetic diversity of the populations via a set of SNP molecular markers were evaluated. These studied showed that the sexual reproduction of Ludwigia grandiflora subsp hexapetala is under the control of a "late-acting" heteromorphic self-incompatibility system of the distyle-homostyle type. We have identified two invasion fronts with two meeting points. The majority efficient breeding system is clonality with an allogamy signal at the level of the 2 diversity hot spots, suggesting management prioritization at their levels. These studies could be extended to other invasion fronts in Europe and the USA.Dans un contexte de succès de colonisation des espèces invasives, la compréhension d’un front d’invasion est essentielle afin d’identifier des leviers de gestion. En France, Ludwigia grandiflora subsp hexapetala a envahi la plupart de réseaux hydrographiques avec des populations fertiles et stériles. Les objectifs de cette thèse étaient l’identification des facteurs influençant sa reproduction sexuée et la caractérisation de sa diversité génétique afin d’inférer le mode de reproduction efficace et de comprendre l’histoire du front d’invasion. La biologie florale et la fructification des populations fertiles et stériles dans différentes conditions climatiques et après différents croisements contrôlés ainsi que la diversité génétique des populations via un set de marqueurs moléculaires SNP ont été évaluées,Ces travaux ont montré que la reproduction sexuée de Ludwigia grandiflora subsp hexapetala est sous contrôle d’un système d’auto-incompatibilité hétéromorphique « à action tardive » de type distyle-homostyle. Nous avons identifié deux fronts d’invasion avec deux points de rencontre. Le système de reproduction efficace majoritaire est la clonalité avec un signal d’allogamie au niveau des 2 « hot-spot » de diversité, suggérant une priorisation de gestion à leurs niveaux. Ces études pourront être étendues à d’autres fronts d’invasion en Europe et aux USA

Knowledge on the biomedical and cosmetic usage of macrofungi

International audienceFungi are ecologically diverse organisms distributed worldwide. From estimated 1.5-3 million species, about 150,000 are macrofungi (mushrooms). About 10% (14,000-16,000 species) of known macrofungi, of which 7000 are considered edible and 500 poisonous species. There may be as many as 700 species which are considered safe and possess around 130 pharmacological activities. The present work reviews the current state of knowledge and the main findings of previous studies on mycotherapeutics and is an update contribution to modern mycopharmacology and mycocosmetology.Badalyan SM, Barkhudaryan A, Rapior S Medicinal macrofungi as cosmeceuticals: A review. Int.J.Med.Mushrooms, 24 (4), 1-13 (2022) ; Diallo I, Boudard F, Morel S, Vitou M, Guzman C, Saint N, Michel A, Rapior S, Traoré L, Poucheret P, Fons F. Antioxidant and anti-inflammatory potential of Shiitake culinary-medicinal mushroom, Lentinus edodes (Agaricomycetes), sporophores from various culture conditions. Int.J.Med.Mushrooms, 22 (6), 535-546 (2020)

Genomic relationships among diploid and polyploid species of the genus Ludwigia L. section Jussiaea using a combination of molecular cytogenetic, morphological, and crossing investigations

International audienceThe genus Ludwigia L. section Jussiaea is composed of a polyploid species complex with 2x, 4x, 6x and 10x ploidy levels, suggesting possible hybrid origins. The aim of the present study is to understand the genomic relationships among diploid and polyploid species in the section Jussiaea. Morphological and cytogenetic observations, controlled crosses, genomic in situ hybridization (GISH), and flow cytometry were used to characterize species, ploidy levels, ploidy patterns, and genomic composition across taxa. Genome sizes obtained were in agreement with the diploid, tetraploid, hexaploid, and decaploid ploidy levels. Results of GISH showed that progenitors of Ludwigia stolonifera (4x) were Ludwigia peploides subsp.montevidensis (2x) and Ludwigia helminthorrhiza (2x), which also participated for one part (2x) to the Ludwigia ascendens genome (4x). Ludwigia grandiflora subsp. hexapetala (10x) resulted from the hybridization between L. stolonifera (4x) and Ludwigia grandiflora subsp.grandiflora (6x). One progenitor of L. grandiflora subsp. grandiflora was identified as L. peploides (2x). Our results suggest the existence of several processes of hybridization, leading to polyploidy, and possibly allopolyploidy, in the section Jussiaea due to the diversity of ploidy levels. The success of GISH opens up the potential for future studies to identify other missing progenitors in Ludwigia L. as well as other taxa

Salivary proteins of Phloeomyzus passerinii, a plant-manipulating aphid, and their impact on early gene responses of susceptible and resistant poplar genotypes

International audienceSuccessful plant colonization by parasites requires the circumvention of host defenses, and sometimes a reprogramming of host metabolism, mediated by effector molecules delivered into the host. Using transcriptomic and enzymatic approaches, we characterized salivary glands and saliva of Phloeomyzus passerinii, an aphid exhibiting an atypical feeding strategy. Plant responses to salivary extracts of P. passerinii and Myzus persicae were assessed with poplar protoplasts of a susceptible and a resistant genotype, and in a heterologous Arabidopsis system. We predict that P. passerinii secretes a highly peculiar saliva containing effectors potentially interfering with host defenses, biotic stress signaling and plant metabolism, notably phosphatidylinositol phosphate kinases which seemed specific to P. passerinii. Gene expression profiles indicated that salivary extracts of M. persicae markedly affected host defenses and biotic stress signaling, while salivary extracts of P. passerinii induced only weak responses. The effector-triggered susceptibility was characterized by downregulations of genes involved in cytokinin signaling and auxin homeostasis. This suggests that P. passerinii induces an intracellular accumulation of auxin in susceptible host genotypes, which is supported by histochemical assays in Arabidopsis. This might in turn affect biotic stress signaling and contribute to host tissue manipulation by the aphid

Hypomethylation of the aquatic invasive plant, Ludwigia grandiflora subsp. hexapetala mimics the adaptive transition into the terrestrial morphotype

International audienceOngoing global changes affect ecosystems and open up new opportunities for biological invasion. The ability of invasive species to rapidly adapt to new environments represents a relevant model for studying short‐term adaptation mechanisms. The aquatic invasive plant, Ludwigia grandiflora subsp. hexapetala, is classified as harmful in European rivers. In French wet meadows, this species has shown a rapid transition from aquatic to terrestrial environments with emergence of two distinct morphotypes in 5 years. To understand the heritable mechanisms involved in adjustment to such a new environment, we investigate both genetic and epigenetic as possible sources of flexibility involved in this fast terrestrial transition. We found a low overall genetic differentiation between the two morphotypes arguing against the possibility that terrestrial morphotype emerged from a new adaptive genetic capacity. Artificial hypomethylation was induced on both morphotypes to assess the epigenetic hypothesis. We analyzed global DNA methylation, morphological changes, phytohormones and metabolite profiles of both morphotype responses in both aquatic and terrestrial conditions in shoot and root tissues. Hypomethylation significantly affected morphological variables, phytohormone levels and the amount of some metabolites. The effects of hypomethylation depended on morphotypes, conditions and plant tissues, which highlighted differences among the morphotypes and their plasticity. Using a correlative integrative approach, we showed that hypomethylation of the aquatic morphotype mimicked the characteristics of the terrestrial morphotype. Our data suggest that DNA methylation rather than a new adaptive genetic capacity is playing a key role in L. grandiflora subsp. hexapetala plasticity during its rapid aquatic to terrestrial transition