Intrinsic determinants of mango tree growth and reproduction: Consequences on functional-structural modeling

International audienceno abstrac

Effects of pruning on the apple tree: from tree architecture to modeling

International audienceArboricultural practices such as pruning, artificial bending or fruit thinning are crucial interventions in orchard management and are used for controlling tree size, penetration of light into the canopy and the equilibrium between vegetative and reproductive growth. The aim of this project is to explore the possibility of integrating such practices in a model of apple tree development. To this end we designed field experiments to study the effects of pruning (thinning or heading cuts) on two apple cultivars with contrasted architecture, ?Fuji? and ?Braeburn?. The results of these first experiments showed that the studied cultivars had significantly different reactions to pruning: ?Braeburn? trees were penalized more than ?Fuji? trees in terms of the total number of internodes despite the fact that a greater number of internodes had developed. Thinning cuts of laterals tended to be compensated by an increase in lateral branching. Results also indicated that trees which had been pruned tended to develop trunks with similar number of internodes than control trees (which were not pruned). These experiments constitute a first step for assessing the rules underlying tree responses to pruning, which will be further integrated in a model of growth

Deciphering mango tree asynchronisms using Markov tree and probabilistic graphical models

ISBN 978-951-651-408-9International audienceTree development is often characterised by complex dependencies between daughter growth units (GUs) deriving from a given mother GU, the so-called sister GUs. These dependencies directly affect the reproductive and vegetative phenological patterns that are at the origin of asynchronisms between adjacent GUs, eventually leading to within-canopy patchiness. These phenomena are rather common on tropical fruit-trees. We introduce new parsimonious statistical models to identify such dependencies. The proposed approach is illustrated on mango tree, a tropical species with a particularly complex timing of development. We focus especially on differences on fates and dates of burst between the daughter GUs issued from a same mother GU

V-Mango: A functional-structural model of mango tree growth, development and fruit production

Background and Aims: Mango (Mangifera indica L.) is the fifth most widely produced fruit in the world. Its cultivation, mainly in tropical and sub-tropical regions, raises a number of issues such as the irregular fruit production across years, phenological asynchronisms that lead to long periods of pest and disease susceptibility, and the heterogeneity of fruit quality and maturity at harvest. To address these issues, we developed an integrative functional–structural plant model that synthesizes knowledge about the vegetative and reproductive development of the mango tree and opens up the possible simulation of cultivation practices. Methods: We designed a model of architectural development in order to precisely characterize the intricate developmental processes of the mango tree. The appearance of botanical entities was decomposed into elementary stochastic events describing occurrence, intensity and timing of development. These events were determined by structural (position and fate of botanical entities) and temporal (appearance dates) factors. Daily growth and development of growth units and inflorescences were modelled using empirical distributions and thermal time. Fruit growth was determined using an ecophysiological model that simulated carbon- and water-related processes at the fruiting branch scale. Key Results: The model simulates the dynamics of the population of growth units, inflorescences and fruits at the tree scale during a growing cycle. Modelling the effects of structural and temporal factors makes it possible to simulate satisfactorily the complex interplays between vegetative and reproductive development. The model allowed the characterization of the susceptibility of mango tree to pests and the investigatation of the influence of tree architecture on fruit growth. Conclusions: This integrative functional–structural model simulates mango tree vegetative and reproductive development over successive growing cycles, allowing a precise characterization of tree phenology and fruit growth and production. The next step is to integrate the effects of cultivation practices, such as pruning, into the model

Integrative models for analyzing jointly shoot growth and branching patterns

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresISBN 978-951-651-408-9International audienceThe branching pattern of a shoot may be influenced by numerous factors varying along the shoot such as the internode length, the leaf surface or the local curvature. We introduce a generalization of hidden semi-Markov chains for categorical response variables that incorporates explanatory variables varying with the index parameter. Using this model, we demonstrate the influence of the growth pattern of a shoot on its immediate branching

Données de (Meta)-génomiques et de (Meta)-transcriptomiques

Données de (Meta)-génomiques et de (Meta)-transcriptomiques . Journées d'Animation ME

Dossier de Candidature pour l'Habilitation à Diriger des Recherches Titres & Travaux de Eric Guédon

Travaux relatifs aux bactéries d’intérêt alimentaire La nutrition azotée et sa régulation chez Lactococcus lactis Contexte scientifique et problématique de recherche : Signalomic des bactéries et des communautés bactériennes d’intérêt alimentair

L'Homme et ses microbes

L'Homme et ses microbes. 15.rencontre G-RREM

Medical and biotechnological applications of extracellular vesicles

Cells in all domains of life (archaea, bacteria, eukaryotes) secrete extracellular vesicles (EVs) into environment and surrounding biofluids. These nanosized membrane vesicles transport biologically active molecules i.e. proteins, lipids, metabolites, and nucleic acids from donor cells to distant recipient cells and act as mediators in cell-to-cell communication by vesicle-mediated direct activation of the target cells or by transferring functional vesicular cargos to the recipient cells. In this way, EVs contributes to health, nutrition and disease. Eukaryotic EVs participate in the regulation of a wide range of physiological (e.g. immune surveillance, tissue repair, blood coagulation) and pathological processes (e.g. induction of local and/or systemic inflammation, proliferation and facilitate tumour metastasis). Prokaryotic EVs play also several functions depending on the bacterial species/strains in pathogenesis, microbiota homeostasis, bacterial survival, gene transfer and host cell modulation. The field of EVs research is quickly growing notably due to their important function in numerous biological processes. In addition to the understanding of their role in health and disease, this field of scientific research have great potential for innovation in medical and biotech sector. By their peculiar properties, EVs are being considered as promising biomarkers for both diagnostic and prognostic purposes, in particular for assessment of health status and treatment responses and outcomes in pathological conditions. EVs offer also possibilities as drug components or drug delivery vehicles for therapeutic intervention in cancer, metabolic, autoimmune and inflammatory disease, regenerative medicine, vaccination against pathogens and anti-bacterial treatment. An overview of the features, functionalities and potential applications of extracellular vesicles with an emphasis on bacterial EVs will be provided here

MicroBio team objectives

MicroBio team objectives. STLOpenday