20 research outputs found

    Screening phytochimique et identification spectroscopique des flavonoïdes d’Asteriscusgraveolenssubsp. odorus

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    Ce travail s’intĂ©resse Ă  l’étude phytochimique d’une espĂšce du Sud du Maroc appartenant Ă  la famille des Asteraceae : Asteriscusgraveolenssubsp. odorus. Le screening phytochimique des feuilles et des fleurs de cette plante, effectuĂ©e pour la premiĂšre fois, a rĂ©vĂ©lĂ© la prĂ©sence des alcaloĂŻdes, des flavonoĂŻdes, des tanins catĂ©chiques, des terpĂšnes, des coumarines et des composĂ©s cyanogĂ©nĂ©tiques. Quant aux saponines et les quinones libres, ils sont prĂ©sents chez les fleurs et absents chez les feuilles. La caractĂ©risation des molĂ©cules par spectrophotomĂ©trie UV a rĂ©vĂ©lĂ© la prĂ©sence de l’acide cafĂ©ique, nĂ©vadensine, lutĂ©oline et artemĂ©tine dans les feuilles d’Asteriscus graveolens subsp. odorus.Mots-clĂ©s : analyse spectrophotomĂ©trique, screening phytochimique, asteriscus graveolens subsp. odorus

    Plant and Aphid Partners of Poleroviruses: Role in Virus Transmission by Aphids?

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    Comité de lecture : trueConférence invitée : falseDate de début de l'événement : 2011-07-11Date de fin de l'évenement : 2011-07-14Date de validation : Tue Aug 13 15:11:30 CEST 2013Diffusion de la piÚce jointe : Publique, PubliqueIdentifiant : 200587Langue du titre : engNombre de consultation de la notice : 77Nombre de téléchargements de la piÚce jointe : 8Pays de l'événement : BRAPublic visé : ScientifiqueType de communication avec actes : Présentation oraleType d'événement : SymposiumPoleroviruses are phloem limited viruses strictly transmitted by aphids in a circulative and non propagative manner. Virions are acquired by aphids when ingesting sap from infected plants. Virus particles cross the gut epithelium and the accessory salivary gland cells before being released, together with saliva, into the plant during a subsequent feed. This highly specific transcytosis mechanism relies on the presence of virus receptors on the surface of the aphid cells. We developed several approaches to identify virus partners in the plant and in the aphid to analyse their role in virus transmission by the vector. By screening different aphid cDNA libraries using a yeast two hybrid system, only few candidates were able to bind virus structural proteins. Among them, we found two nuclear proteins (GAR1 and ALY) which may not be the true virusreceptors but could be considered as virus-sensors. An Ephrin receptor-like protein was also found to interact with the viral proteins. Involvement of these candidates in virus transport through the aphid needs to be analyzed by developing in the insect RNAi-based techniques. These experiments are in progress. We also looked for plant virus-partners and identified several phloem proteins able to bind purified virions in vitro. We showed that these proteins could stimulate virus transmission by aphids when added together with purified virus to the aphid diet (Bencharki et al. 2010, M.P.M.I., 23: 799). By developing a yeast two hybrid system using a phloem specific cDNA library, we identified five additional proteins able to bind viral proteins. Among them, we found ALY proteins already identified as aphid virus-partners suggesting that orthologous plant and aphid proteins could be implicated in the virus cycle. So far, a direct implication of these proteins in aphid transmission has not been observed and experiments are on going to analyze their functions

    Sélection de nouvelles lignées de blé tendre hautement productives et résistantes à la cécidomyie, Mayetiola destructor (Say), au Maroc

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    Le blĂ© (Triticum sp.) constitue l’alimentation de base de la population Marocaine. Toutefois, cette culture est attaquĂ©e par plusieurs maladies et ravageurs, dont la mouche de Hesse. Cet insecte est le ravageur le plus redoutable du blĂ©, causant des pertes annuelles en rendement de plus de 30%. Dans le but de sĂ©lectionner un germoplasme qui combine la rĂ©sistance Ă  la cĂ©cidomyie, Mayetiola destructor (Say), et un haut potentiel de rendement, une pĂ©piniĂšre de blĂ© tendre HF_SBWYT_MOR_ON de 160 lignĂ©es provenant de l’ICARDA (International Center for Agricultural Research in the Dry Areas) a Ă©tĂ© Ă©valuĂ©e pour la rĂ©sistance Ă  la cĂ©cidomyie de blĂ© et pour le potentiel de rendement sous serre, et dans quatre environnements (sites) du Maroc: Chaouia, Abda, Doukkala et Tadla, reprĂ©sentĂ©s par les domaines expĂ©rimentaux de Sidi El Aidi, Jemaa Shaim, Khemis Zemamra et Deroua. L'analyse de la variance a montrĂ© des effets hautement significatifs (P<0,0001) des paramĂštres site, gĂ©notype et l’interaction site x gĂ©notype, pour les tests de rĂ©sistance Ă  la cĂ©cidomyie ou de rendement grain. L’évaluation sous serre a rĂ©vĂ©lĂ©que 87,5% des lignĂ©es de la pĂ©piniĂšre sont rĂ©sistantes, 9,4 % hĂ©tĂ©rogĂšnes et 3,1 sensibles. Les lignĂ©es sont dĂ©rivĂ©es de parents rĂ©sistants et expriment l’antibiosis comme mĂ©canisme de rĂ©sistance. Les meilleurs rendements en grain ont Ă©tĂ© obtenus dans la station expĂ©rimentale de Deroua conduite sous rĂ©gime irrigué : 23,7 Ă  86 qx/ha dĂ©passant largement la moyenne nationale (18 qx/ha). Les plus faibles rendements ont Ă©tĂ© obtenus Ă  Khemis Zemamra: 7,7 Ă  41,3 qx/ha.

    Two distinct nanovirus species infecting faba bean in Morocco

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    Using monoclonal antibodies raised against a Faba bean necrotic yellows virus (FBNYV) isolate from Egypt and a Faba bean necrotic stunt virus (FBNSV) isolate from Ethiopia, a striking serological variability among nanovirus isolates from faba bean in Morocco was revealed. To obtain a better understanding of this nanovirus variability in Morocco, the entire genomes of two serologically contrasting isolates referred to as Mor5 and Mor23 were sequenced. The eight circular ssDNA components, each identified from Mor5- and Mor23-infected tissues and thought to form the complete nanovirus genome, ranged in size from 952 to 1,005 nt for Mor5 and from 980 to 1,004 nt for Mor23 and were structurally similar to previously described nanovirus DNAs. However, Mor5 and Mor23 differed from each other in overall nucleotide and amino acid sequences by 25 and 26%, respectively. Mor23 was most closely related to typical FBNYV isolates described earlier from Egypt and Syria, with which it shared a mean amino acid sequence identity of about 94%. On the other hand, Mor5 most closely resembled a FBNSV isolate from Ethiopia, with which it shared a mean amino acid sequence identity of approximately 89%. The serological and genetic differences observed for Mor5 and Mor23 were comparable to those observed earlier for FBNYV, FBNSV, and Milk vetch dwarf virus. Following the guidelines on nanovirus species demarcation, this suggests that Mor23 and Mor5 represent isolates of FBNYV and FBNSV, respectively. This is the first report not only on the presence of FBNSV in a country other than Ethiopia but also on the occurrence and complete genome sequences of members of two nanovirus species in the same country, thus providing evidence for faba bean crops being infected by members of two distinct nanovirus species in a restricted geographic area

    Zona ophtalmique chez un nourrisson

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