Transgenic technologies for enhanced molecular breeding of white clover (Trifolium repens L.)

White clover is an important pasture legume of temperate regions, generally through co-cultivation with a pasture grass in a mixed-sward setting. White clover provides herbage with high nutritional quality to grazing animals, along with the environmental benefit of biological nitrogen fixation. Several key agronomic traits are amenable to modification in white clover through use of transgenic technology. Efficient methods for Agrobacterium-mediated transformation of white clover have been developed. The current status of transgenic research is reviewed for the following traits: resistance to viruses and insect pests; aluminium tolerance and phosphorus acquisition efficiency; control of leaf senescence and seed yield; biosynthesis of flavonoids and rumen bypass proteins for bloat safety and enhanced ruminant nutrition; cyanogenesis; and drought tolerance. Future prospects for transgenic technology in molecular breeding in white clover are also discussed.