N. benthamiana leaf phenotype at different days after agro-infiltration with the fusion and control constructs. a) leaf phenotype at the end of the experiments 1 & 2. b) Ratio of total ketocarotenoids calculated by dividing the total ketocarotenoid content of pZ-W (fusion) by that of the pZ+W (individual). Control, non agro-infiltrated; p-Ø, empty vector; pZ-x-W, fusion enzymes with different size linker (x = small, medium or long); pZ+W, individual enzymes.