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 pièce jointe : Publique, PubliqueIdentifiant : 200587Langue du titre : engNombre de consultation de la notice : 77Nombre de téléchargements de la pièce 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