Metal Interactions in the Ni Hyperaccumulating Population of Noccaea caerulescens Monte Prinzera

Simple Summary: Hyperaccumulation is a particular trait that has evolved in a few plant species, conferring upon them the ability to accumulate large amounts of metal ions in above-ground tissues without showing symptoms of toxicity. Noccaea caerulescens is a model system to study metal hyperaccumulation and hypertolerance, since a significant number of populations exist, characterized by a wide variety of metal tolerance and accumulation. In this report, the serpentine population Monte Prinzera of N. caerulescens was treated with excess Ni, Zn and Co and subjected to Fe and Zn deficiency. Transcript analysis, correlated with tissue metal quantification, confirmed that this population was Ni, but not Zn, hypertolerant and hyperaccumulating. Moreover, excess Ni does not induce Fe deficiency as in Ni-sensitive species. Hyperaccumulation is a fascinating trait displayed by a few plant species able to accumulate large amounts of metal ions in above-ground tissues without symptoms of toxicity. Noccaea caerulescens is a recognized model system to study metal hyperaccumulation and hypertolerance. A N. caerulescens population naturally growing on a serpentine soil in the Italian Apennine Mountains, Monte Prinzera, was chosen for the study here reported. Plants were grown hydroponically and treated with different metals, in excess or limiting concentrations. Accumulated metals were quantified in shoots and roots by means of ICP-MS. By real-time PCR analysis, the expression of metal transporters and Fe deficiency-regulated genes was compared in the shoots and roots of treated plants. N. caerulescens Monte Prinzera confirmed its ability to hypertolerate and hyperaccumulate Ni but not Zn. Moreover, excess Ni does not induce Fe deficiency as in Ni-sensitive species and instead competes with Fe translocation rather than its uptake.