Abstract:

Leymus chinensis is an important native forage grass， which is widely distributed in the Inner Mongolian steppe grasslands of China. However， the molecular mechanism of mineral uptake in L. chinensis is not yet well understood， although it is known from systematic study in many model plants and crops that zinc-regulated transporter/iron-regulated transporter-like proteins （ZIP transporters） are involved in the uptake and allocation of essential trace elements and heavy metal ions. In this study we found that the Lc206852 gene screened from the L. chinensis transcriptome database was homologous with Zn²⁺ transporter AtZIP1 in Arabidopsis thaliana. Transmembrane domain analysis using TMHMM Server v. 2.0 indicated that Lc206852， referred to hereafter as LcZIP1， had 9 transmembrane domains， which were closely related to ZIP proteins of plants of the genus Brachypodium. Expression of LcZIP1-GFP in leaf epidermal cells of tobacco and leaf protoplasts of L. chinensis showed that LcZIP1 resided in the endoplasmic reticulum. Real time PCR analysis found that LcZIP1 was responsive to zinc and iron nutrition， and that excess Zn or Fe and^{Fe deficiency induced LcZIP1 expression in roots at transcription level. The yeast （Saccharomyces cerevisiae） complementation test showed that expression of LcZIP1 stimulated growth of the ‘iron uptake-deficient’ yeast mutant ?fet3/?fet4 under Fe deficient conditions. Functional characterization of LcZIP1 willprovide an opportunity for crop improvement by mineral nutrition enhancement in the future.}

Key words: Leymus chinensis, iron, ZIP transporters, yeast complementation