Unrooted tree that highlights the relationship among the zinc transporter proteins in different plant species. At, Arabidopsis; Gm, soybean (Glycine max); Tc, T. caerulescens; Os, rice; Sc, S. cerevisiae; Mt, Medicago truncatula; Ps, pea; Le, tomato (Lycopersicon esculentum). GenBank identification numbers are provided next to each protein.