Systemic upregulation of Zn partitioning to the shoot supplements local Zn-deficiency responses (Plant Cell)

Zinc is an important micronutrient for plants and people. To better understand Zn uptake and homeostasis, Sinclair et al. used a transcriptomic approach to identify genes abnormally expressed in zinc-transporter mutants (hma2 hma4). In these mutants, Zn accumulates in roots but isn’t effectively transported to shoots. The authors found that MTP2 (encoding a metal transporter protein) is highly expressed in roots of shoot Zn-deficient plants, indicating that a systemic signal from shoot to root controls its expression. Interestingly, MTP2 accumulates on the ER membrane.  The authors suggest that its function is to transport Zn into the ER lumen, facilitating its movement from cell-to-cell via plasmadematal desmotubules. (Summary by Mary Williams) Plant Cell 10.1105/tpc.18.00207