 The gene is then transiently expressed through RNA synthesis from appropriate promoter sequences in all transfected cells (no selection for stable integration is performed).The plant can be monitored for a possible effect in the phenotype, subjected to experimental conditions or harvested and used for purification of the protein of interest.Many plant species can be processed using this method, but the most common ones are "Nicotiana benthamiana" and less often, "Nicotiana tabacum".