Cloning of ZIP family metal transporter genes from the manganese hyperaccumulator plant Chengiopanax sciadophylloides, and its metal transport and resistance abilities in yeast

Abstract

Manganese (Mn) specific hyperaccumulation in the tree Chengiopanax sciadophylloides in soil not polluted by metals has received attention as a distinctive character of this plant, but its mechanism has not yet been clarified. Based on the speculation that ZIP (Zrt-, Irt-like proteins) transporters of high Mn affinity are involved in Mn-specific hyperaccumulation in this plant, we isolated ZIP family transporter gene homologs and investigated their metal transport characteristics in yeast cells. An isolated Zip gene homolog, designated as CsZIP1, coded a protein of 475 amino acids in length and showed 65% or lower sequence identity with ZIPs of other herbal plants. Expression of this gene was induced in the callus of Mn-deficient C. sciadophylloides. However, its expression did not rescue the Mn transport ability of yeast lacking the Mn transporter gene smf1. CsZIP1 did not show Zn and Fe transport, but its expression increased Cd sensitivity and Ni tolerance of wild-type yeast. © 2008 Japanese Society of Soil Science and Plant Nutrition.