Arabidopsis halleri ssp. gemmifera and its relatives as a model of metal accumulating plants

Abstract

Metal hyperaccumulators are defined as plants containing extremely high concentrations of metals in their shoots. Several subspecies of Arabidopsis halleri hyperaccumulate Zn/Cd and are closely related to the genetic model plant A. thaliana. In this review, the recent progress of the characterization of metal accumulation in A. halleri were summarized, especially in A. halleri ssp. gemmifera, growing in East Asia. We also focused on the intraspecific natural variation to elucidate the metal homeostasis in A. halleri ssp. gemmifera, and collected the accessions from a limestone mining site on Mt. Ibuki, and compared them with those collected from non-calcareous soil in Japan. The plants growing on non-calcareous soil also accumulated Zn in shoot tissues, but shoot Zn concentrations in plants growing on calcareous soils were below the level required for hyperaccumulators. Furthermore, comparing analyses of Arabidopsis spp. were discussed as a valuable tool for the elucidation of phenotypic differences, not only metal homeostasis but molecular evolution of self-fertilisation, chromosomal rearrangement.