In order to be able to use phytoremediation practices successfully it is necessary to gain knowledge on the behaviour and fate of the metals in soil-plant systems. Metal hyperaccumulator plants such as Thlaspi caerulescens of the Brassicaceae family represent an excellent model to study physiological and molecular mechanisms of metal uptake, transport, accumulation and tolerance due to their physiological, morphological and genetic characteristics, and their close relationship to Arabidopsis thaliana, the general plant reference species. In this chapter, the progress that has been made in elucidating molecular and physiological mechanisms of metal hyperaccumulation in Thlaspi caerulescens (a model Zn, Cd and Ni hyperaccumulator) and its relative T. praecox (a Cd and Zn hyperaccumulator) will be reviewed briefly. A special emphasis will be placed on hyperaccumulation of cadmium and interactions of the Thlaspi spp. with symbiotic arbuscular mycorrhizal fungi as these topics still need to be more intensively explored.
Keywords: Arabidopsis halleri, Brassicaceae, citrate, Cys-rich proteins, Glomus species, glucosinolates, glucotropaeolin, hypertolerance, malate, metal transporters, metallophytes, metallotioneins, nicotianamine, organic acids, phytomining, ATP-ase, Thlaspi caerulescens, Thlaspi praecox, vacuolar sequestration, ZIP family.