It has been well demonstrated that the Cauliflower mosaic virus or CaMV activates its own transmission at this very moment when the aphid vector penetrates the infected plant cell. This Transmission Activation or TA mecanism suggests that the CaMV is able to detect the aphid presence, such phenomenon has never occured before. The main objective of this internship is to determine whether another virus the Cucumber mosaic virus posseses the TA mecanism. For this purpose, transmission tests were done from CaMV infected protoplasts and were adapted to CMV just before proceeding to transmission tests with conditions which modify CaMV transmission. In parallel immunostaining and western blotting were made to detect a possible phenotype of CMV Transmission Activation. CMV can be acquired from a protoplast, but the protocol still needs to be improved so that we may infer a possible TA mecanism. Immnostainning reveals a CMV phenotype modification in the presence of NaN3, salicylic acid, thermal shock and latrunculin.