The aim of this project is to decrease the levels of the carcinogenic compounds, the polycyclic aromatic hydrocarbons (PAH), in cigarette smoke. This amount is tightly related to the amount of cellulose in tobacco. The identification and the characterisation of new proteins that are involved in cellulose synthesis and/or deposition of cellulose microfibrils in Arabidopsis thaliana are being identified in the Cellular Biology Laboratory. This data will help us to identify the orthologous genes in tobacco and to modify the cellulose amount by overexpressing or silencing the expression of these genes in tobacco. Our main objective is to analyse the PAH amount in these plants and then try to find a specific variety of tobacco with low amount of PAH.