High phytosterol variants towards improved feedstocks and biofortification of crops
Phytosterols (PS) are valuable biomolecules used as nutrients and as feedstock material for the pharmaceutical and cosmetic industries. The challenge biologists and breeders are faced with is to develop bioengineering programs and valuable crops dedicated to the large-scale production of PS, which are currently extracted from agricultural waste materials. The goal of the proposal is to identify master regulators of PS biosynthesis and accumulation in plants. In fact, PS have essential cellular functions in plant growth and development, acting as key membrane components and membrane reinforcers, as signals in development and as precursors of brassinosteroids, a class of growth regulators. As such, the concentration of PS is highly regulated in order to comply with cellular homeostasis. To reach the goal, we will carry out a functional molecular characterization of a tobacco variant carrying a yet unknown semi-dominant mutation responsible for PS overproduction and  Arabidopsis thaliana mutants exhibiting a suppressor phenotype of a defect in the production of precursors of isoprenoid lipids, such as PS. The work plan is to apply advanced genomics for next-generation mapping, leading to the elucidation of mutations in genes of interest (GOI) that regulate PS accumulation. The validation of candidate GOI will be done by genome editing and the role of novel alleles in PS metabolism will be performed by various functional and metabolomic studies. Finally, the combined expression of selected GOI with steroidogenic enzymes will be assessed by implementing in folia expression assays in Nicotiana benthamiana.