Genome-Wide Investigation and Functional Verification of the ZIP Family Transporters in Wild Emmer Wheat.

Fangyi Gong,Dengcai Liu,Yanling Hu,Yarong Jin,Lianquan Zhang,Bo Jiang,Jingshu He,Bin Tu,Lin Huang,Wenyang Wang,Yi Wang,Tao Zhang,Youliang Zheng,Bihua Wu,Jia Liu,Tiangang Qi

doi:10.3390/ijms23052866

Abstract

The zinc/iron-regulated transporter-like protein (ZIP) family has a crucial role in Zn homeostasis of plants. Although the ZIP genes have been systematically studied in many plant species, the significance of this family in wild emmer wheat (Triticum turgidum ssp. dicoccoides) is not yet well understood. In this study, a genome-wide investigation of ZIPs genes based on the wild emmer reference genome was conducted, and 33 TdZIP genes were identified. Protein structure analysis revealed that TdZIP proteins had 1 to 13 transmembrane (TM) domains and most of them were predicted to be located on the plasma membrane. These TdZIPs can be classified into three clades in a phylogenetic tree. They were annotated as being involved in inorganic ion transport and metabolism. Cis-acting analysis showed that several elements were involved in hormone, stresses, grain-filling, and plant development. Expression pattern analysis indicated that TdZIP genes were highly expressed in different tissues. TdZIP genes showed different expression patterns in response to Zn deficiency and that 11 genes were significantly induced in either roots or both roots and shoots of Zn-deficient plants. Yeast complementation analysis showed that TdZIP1A-3, TdZIP6B-1, TdZIP6B-2, TdZIP7A-3, and TdZIP7B-2 have the capacity to transport Zn. Overexpression of TdZIP6B-1 in rice showed increased Zn concentration in roots compared with wild-type plants. The expression levels of TdZIP6B-1 in transgenic rice were upregulated in normal Zn concentration compared to that of no Zn. This work provides a comprehensive understanding of the ZIP gene family in wild emmer wheat and paves the way for future functional analysis and genetic improvement of Zn deficiency tolerance in wheat.

Highlights

Zinc (Zn) is one of the most essential micronutrients for plants and humans and plays a critical role in diverse biochemical processes [1,2]
A total of 33 putative zinc/iron-regulated transporter-like protein (ZIP) genes were identified and confirmed from the wild emmer reference genome. These ZIP genes were tentatively designated as TdZIP1A-1 to TdZIP7B-3 (Table 1) according to their locations on chromosomes
We found that these ZIPs were unevenly distributed on the chromosomes, with 16 and 17 genes positioned on the A and B chromosomes, respectively (Table 1, Figure S1)

Summary

Introduction

Zinc (Zn) is one of the most essential micronutrients for plants and humans and plays a critical role in diverse biochemical processes [1,2]. Zn is irreplaceable for plant normal growth and development [3]. Both deficient and excess Zn has negative effects on the physiological and biochemical processes of the plant [4]. It was estimated that one-third of the world’s population suffers from inadequate intake of Zn, resulting in various health problems [5–7]. A foodbased strategy (biofortification) is considered the most cost effective and sustainable option for improvement of human health [8]. Improving the Zn nutrition in crop varieties is an important goal of both public and private breeding programs to overcome the Zn deficiency problem

Methods

Results

Conclusion