TRIACYLGLYCEROLS (TAGS, THE MAIN COMPONENT OF PLANT OILS), ARE THE MOST ENERGY-DENSE CARBON RESERVES PRODUCED BY PLANTS, AND SUPPLY HUMANS WITH MUCH OF THE CALORIES AND ESSENTIAL FATTY ACIDS (FAS) REQUIRED IN OUR DIET. ADDITIONALLY, VARIOUS PLANT TAGS HAVE UNIQUE PROPERTIES THAT CAN BE USED AS FEEDSTOCKS FOR THE COSMETIC AND CHEMICAL INDUSTRIES TO MAKE A LARGE RANGE OF VALUABLE PRODUCTS. THE USE AND VALUE OF PLANT OILS FOR EACH APPLICATION IS DEPENDENT ON THE FA COMPOSITION OF THE OIL. DESPITE OVER 50 YEARS OF RESEARCH, THERE HAS BEEN ONLY LIMITED SUCCESS IN ACCURATELY MODIFYING THE FA COMPOSITION OF SEED OILS TO DESIRED COMPOSITIONS. RECENTLY, WE DISCOVERED A NOVEL METABOLIC PATHWAY OF OIL BIOSYNTHESIS, COINED TAG REMODELING, IN THE BRASSICACEAE SPECIES PHYSARIA FENDERLI. TAG REMODELING INVOLVES AN INITIAL TAG SYNTHESIS, PARTIAL DEGRADATION, AND RESYNTHESIS CYCLE THAT ALLOWS THE INCORPORATION OF FAS INTO TAG THAT ARE NOT COMPATIBLE WITH THE MEMBRANE LIPID INTERMEDIATES OF INITIAL TAG BIOSYNTHESIS. WE HYPOTHESIZE THAT TAG REMODELING IS PRESENT IN OTHER BRASSICACEAE SPECIES (INCLUDING MAJOR OILSEED CROPS) AND IS CRUCIAL FOR CONTROLLING THE FINAL OIL FA COMPOSITION. WITHIN THIS PROPOSAL WE WILL: (1) INVESTIGATE THE PRESENCE OF TAG REMODELING IN FIVE CURRENT BRASSICACEAE CROPS; (2) CHARACTERIZE THE PROPERTIES OF TAG BIOSYNTHESIS/TURNOVER ENZYMES FOR THEIR ABILITY TO PRODUCE DIFFERENT TAG FA COMPOSITIONS; AND (3) EVALUATE IF MODULATION OF TAG REMODELING FUNCTION (BY EITHER DECREASING OR INCREASING ACTIVITY) CAN BE A TOOL FOR CONTROLLING SEED OIL FA COMPOSITION AND GENERATING THE DESIGNER OILSEEDS OF THE FUTURE.