Influences réciproques des racines et des parties aériennes sur le rendement de l'aubergine (Solanum melongena L.) : résultats de greffages inter-variétaux

Afin de mesurer les effets de la croissance racinaire et des parties aériennes sur la production de l’aubergine de plein champ irriguée, les racines et les parties aériennes d’une variété méditerranéenne ont été échangées par greffage avec celles d’une variété venant d’Extrême-Orient. Les performances des plantes inter-écotypiques montrent que les racines et le feuillage ont des influences réciproques et équivalentes sur le nombre de fruits ; par contre, le développement racinaire a une influence prédominante sur le poids moyen des fruits. Aussi avec une croissance aérienne et racinaire supérieure, la variété méditerranéenne a le meilleur rendement en culture irriguée de plein champ dans le Sud de la France.Measurements have been made of the effects of root growth and shoot development on irrigated eggplant fruit production. Roots and shoots of a Mediterranean variety and an other from the Far East were exchanged by grafting. Growth and fruit production of these inter-ecotype plants (tables 1 & 2) showed that roots and shoots had an equal and reciprocal influence on fruit number, whereas the root growth effect was mainly on mean fruit weight. Therefore with better root and shoot growth, the Mediterranean variety has the largest fruit production under irrigation in the south of France

Les reines mortes du Portugal / Philippe Jullian

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Gestion concertée de la biodiversité, agriculture et développement local en montagne

Contrat ; 121601 ; SUACI-GIS Alpes du NordNational audienceL'article concerne les modes de construction de projets de gestion concertés de la biodiversité impliquant gestionnaires de l'environnement, acteurs agricoles et autres acteurs locaux. Les auteurs s'appuient sur les premiers résultats d'un programme de recherche/développement concernant les conditions de réussite et d'échec de projets de gestion de la biodiversité dans les espaces agricoles et pastoraux nord alpin. Dans ce programme, les auteurs étudient une diversité de projets tant du point de vue institutionnel (espaces protégés, sites Natura 2000, mesures agri-environnementales), que de celui des objectifs de gestion de la biodiversité (espèces qualifiées de "patrimoniales" par les acteurs de l'environnement, espèces végétales et animales protégées, habitats d'intérêt communautaire, corridors biologiques ou écologiques) ou de celui des acteurs impliqués (associations de protection de la nature, organismes publics de gestion de la nature, collectivités locales, agriculteurs, organisations professionnelles agricoles). Après une présentation du contexte sociétal et des méthodes de travail, les auteurs s'intéressent à partir d'exemples concrets, aux difficultés d'une gestion concertée de la biodiversité. Cette analyse des conditions dans lesquelles différents acteurs parviennent ou non à un accord local pour la gestion d'espaces agricoles associant objectifs de protection, production agricole, voire parfois objectifs des collectivités locales (valorisation touristique, multi-usages pour les habitants) permet aux auteurs de repérer quelques conditions de réussite de tels projets en particulier du point de vue de l'adhésion des agriculteurs

Facteurs agro-climatiques influençant la résistance stomatique de l'aubergine (Solanum melongena L.)

International audienc

Fréquences stomatiques de l'aubergine (Solanum melongena L.) et relations avec le développement racinaire

International audienc

Enhanced Stilbene Production and Excretion in Vitis vinifera cv Pinot Noir Hairy Root Cultures

Stilbenes are defense molecules produced by grapevine in response to stresses including various elicitors and signal molecules. Together with their prominent role in planta, stilbenes have been the center of much attention in recent decades due to their pharmaceutical properties. With the aim of setting up a cost-effective and high purity production of resveratrol derivatives, hairy root lines were established from Vitis vinifera cv Pinot Noir 40024 to study the organ-specific production of various stilbenes. Biomass increase and stilbene production by roots were monitored during flask experiments. Although there was a constitutive production of stilbenes in roots, an induction of stilbene synthesis by methyl jasmonate (MeJA) after 18 days of growth led to further accumulation of ε-viniferin, δ-viniferin, resveratrol and piceid. The use of 100 µM MeJA after 18 days of culture in the presence of methyl-β-cyclodextrins (MCDs) improved production levels, which reached 1034µg/g fresh weight (FW) in roots and 165 mg/L in the extracellular medium, corresponding to five-and 570-foldincrease in comparison to control. Whereas a low level of stilbene excretion was measured in controls, addition of MeJA induced excretion of up to 37% of total stilbenes. The use of MCDs increased the excretion phenomenon even more, reaching up to 98%. Our results demonstrate the ability of grapevine hairy roots to produce various stilbenes. This production was significantly improved in response to elicitation by methyl jasmonate and/or MCDs. This supports the interest of using hairy roots as a potentially valuable system for producing resveratrol derivatives

Caloxin-derived peptides for the inhibition of plasma membrane calcium ATPases

International audiencePlasma membrane calcium ATPases (PMCAs) are a family of transmembrane proteins responsible for the extrusion of cytosolic Ca2+ to the extracellular milieu. They are important players of the calcium homeostasis possibly implicated in some important diseases. The reference inhibitors of PMCA extruding activity are on one hand ortho-vanadate (IC50 in the 30 mM range), and on the other a series of 12- to 20-mer peptides named caloxins (IC50 in the 100 µM scale). As for all integral membrane proteins, biochemistry and pharmacology are difficult to study on isolated and/or purified proteins. Using a series of reference blockers, we assessed a pharmacological window with which we could study the functionality of PMCAs in living cells. Using this system, we screened for alternative versions of caloxins, aiming at shortening the peptide backbone, introducing non-natural amino acids, and overall trying to get a glimpse at the structure-activity relationship between those new peptides and the protein in a cellular context. We describe a short series of equipotent 5-residue long analogues with IC50 in the low µM range

MCH-R1 Antagonist GPS18169, a Pseudopeptide, Is a Peripheral Anti-Obesity Agent in Mice

Melanin-concentrating hormone (MCH) is a 19 amino acid long peptide found in the brain of animals, including fishes, batrachians, and mammals. MCH is implicated in appetite and/or energy homeostasis. Antagonists at its receptor (MCH-R1) could be major tools (or ultimately drugs) to understand the mechanism of MCH action and to fight the obesity syndrome that is a worldwide societal health problem. Ever since the deorphanisation of the MCH receptor, we cloned, expressed, and characterized the receptor MCH-R1 and started a vast medicinal chemistry program aiming at the discovery of such usable compounds. In the present final work, we describe GPS18169, a pseudopeptide antagonist at the MCH-R1 receptor with an affinity in the nanomolar range and a Ki for its antagonistic effect in the 20 picomolar range. Its metabolic stability is rather ameliorated compared to its initial parent compound, the antagonist S38151. We tested it in an in vivo experiment using high diet mice. GPS18169 was found to be active in limiting the accumulation of adipose tissues and, correlatively, we observed a normalization of the insulin level in the treated animals, while no change in food or water consumption was observed