Transport engineering of glucosinolates for future Brassica crops

Glucosinolates (GLS) are key defense metabolites in brassicaceous plants, but major anti-nutritional (especially goitrogenic) factors in Brassica oilseed crops. In the 1970s, breeding of 'double-low' rapeseed cultivars with canola-quality seeds low in erucic acid and GLS resulted in feed-quality press cake but limited genetic and GLS diversity of the crop. To develop the press cake into protein food, seed GLS levels must be further reduced. Targeting recently identified transporters in Arabidopsis thaliana with key roles in GLS seed loading prevented GLS accumulation in seeds without altering their presence elsewhere in the plant. Transport engineering has potential as a novel breeding approach to decouple seed and leaf GLS, broaden genetic diversity, and improve both seed quality and pest resistance in Brassica oilseed crops.