L' orobanche rameuse en France (le couple orobanche ramosa L. / Nicotiana tabacum L.)

En France, Orobanche ramosa L. est en constante extension dans les cultures de colza d hiver, de tabac et de chanvre textile. Après avoir montré les capacités d adaptation du parasite à de nombreuses cultures, une corrélation a été mise en évidence entre les principaux stades de développement de l orobanche sur tabac et la "somme des températures". La spécificité de la relation hôte/parasite étant une notion très complexe, des recherches analytiques ont été menées sur les exsudats racinaires produits par l hôte et sur la virulence du parasite. L utilisation de marqueurs RAPD a révélé une importante variabilité génétique entre trois populations d O. ramosa récoltées sur trois hôtes différents (colza, tabac et chanvre), suggérant l existence de trois pathovars au sein de l espèce. Un protocole de traitement par l hydrazide maléique, à la fois efficace sur le niveau de l infestation et sur la viabilité des graines d orobanche produites durant l année de culture, a été mis au point.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Two direct targets of cytokinin signaling regulate symbiotic nodulation in Medicago truncatula.

International audienceCytokinin regulates many aspects of plant development, and in legume crops, this phytohormone is necessary and sufficient for symbiotic nodule organogenesis, allowing them to fix atmospheric nitrogen. To identify direct links between cytokinins and nodule organogenesis, we determined a consensus sequence bound in vitro by a transcription factor (TF) acting in cytokinin signaling, the nodule-enhanced Medicago truncatula Mt RR1 response regulator (RR). Among genes rapidly regulated by cytokinins and containing this so-called RR binding site (RRBS) in their promoters, we found the nodulation-related Type-A RR Mt RR4 and the Nodulation Signaling Pathway 2 (NSP2) TF. Site-directed mutagenesis revealed that RRBS cis-elements in the RR4 and NSP2 promoters are essential for expression during nodule development and for cytokinin induction. Furthermore, a microRNA targeting NSP2 (miR171 h) is also rapidly induced by cytokinins and then shows an expression pattern anticorrelated with NSP2. Other primary targets regulated by cytokinins depending on the Cytokinin Response1 (CRE1) receptor were a cytokinin oxidase/dehydrogenase (CKX1) and a basic Helix-Loop-Helix TF (bHLH476). RNA interference constructs as well as insertion of a Tnt1 retrotransposon in the bHLH gene led to reduced nodulation. Hence, we identified two TFs, NSP2 and bHLH476, as direct cytokinin targets acting at the convergence of phytohormonal and symbiotic cues

Effects of diet, packaging, and irradiation on protein oxidation, lipid oxidation, and color of raw broiler thigh meat during refrigerated storage

This study was designed to evaluate the effects of dietary treatment, packaging, and irradiation singly or in combination on the oxidative stability of broiler chicken thigh meat. A total of 120 four-week-old chickens were divided into 12 pens (10 birds/pen), and 4 pens of broilers were randomly assigned to a control oxidized diet (5% oxidized oil) or an antioxidant-added diet [500 IU of vitamin E + 200 mg/kg of butylated hydroxyanisole (BHA)] and fed for 2 wk. After slaughter, thigh meats were separated, ground, packaged in either oxygen-permeable or oxygen-impermeable vacuum bags, and irradiated at 0 or 3 kGy. Lipid oxidation (TBA-reactive substances), protein oxidation (carbonyl), and color of the meat were measured at 1, 4, and 7 d of refrigerated storage. The lipid and protein oxidation of thigh meats from birds fed the diet supplemented with antioxidants (vitamin E + BHA) was significantly lower than the lipid and protein oxidation of birds fed the control diet, whereas the lipid and protein oxidation of broilers fed the oxidized oil diet was higher than that of birds fed the control diet. Vacuum packaging slowed, but irradiation accelerated, the lipid and protein oxidation of thigh meat during storage. Dietary antioxidants (vitamin E + BHA) and irradiation treatments showed a stronger effect on lipid oxidation than on protein oxidation. A significant correlation between lipid and protein oxidation in meat was found during storage. Dietary supplementation of vitamin E + BHA and the irradiation treatment increased the lightness and redness of thigh meat, respectively. It is suggested that appropriate use of dietary antioxidants in combination with packaging could be effective in minimizing oxidative changes in irradiated raw chicken thigh meat.This article is published as Xiao, S., W. G. Zhang, E. J. Lee, C. W. Ma, and D. U. Ahn. "Effects of diet, packaging, and irradiation on protein oxidation, lipid oxidation, and color of raw broiler thigh meat during refrigerated storage." Poultry Science 90, no. 6 (2011): 1348-1357. doi:10.3382/ps.2010-01244.</p

Expertise collective CRREF « Coupes Rases et REnouvellement des peuplements Forestiers en contexte de changement climatique »: Synthèse de l'expertise

Cette synthèse, ainsi que le rapport d’expertise et les exposés du séminaire de restitution, est disponible sur le site web du GIP Ecofor (http://www.gip-ecofor.org/)

Expertise collective CRREF « Coupes Rases et Renouvellement des peuplements Forestiers en contexte de changement climatique » : Rapport scientifique de l’expertise: Rapport scientifique de l'expertise

Cette synthèse, ainsi que le rapport d’expertise et les exposés du séminaire de restitution, estdisponible sur le site web du GIP Ecofor (http://www.gip-ecofor.org/)