Multi-Omics Uncover the Mechanism of Wheat under Heavy Metal Stress

Abstract

Environmental pollution of heavy metals has received growing attention in recent years. Heavy metals such as cadmium, lead and mercury can cause physiological and morphological disturbances which adversely affect the growth and quality of crops. Wheat (Triticum aestivum L.) can accumulate high contents of heavy metals in its edible parts. Understanding wheat response to heavy metal stress and its management in decreasing heavy metal uptake and accumulation may help to improve its growth and grain quality. Very recently, emerging advances in heavy metal toxicity and phytoremediation methods to reduce heavy metal pollution have been made in wheat. Especially, the molecular mechanisms of wheat under heavy metal stress are increasingly being recognized. In this review, we focus on the recently described epigenomics, transcriptomics, proteomics, metabolomics, ionomics and multi-omics combination, as well as functional genes uncovering heavy metal stress in wheat. The findings in this review provide some insights into challenges and future recommendations for wheat under heavy metal stress.

Keywords: functional genes; heavy metal stress; multi-omics; omics; wheat.

Figure 1

Multi-omics reveal the mechanism of wheat under heavy metal stress. Epigenomics (a), transcriptomics (b), proteomics (c) and metabolomics (d) reveal heavy metal stress in wheat. DEGs, differentially expressed genes. DMs, differential metabolites. Up red arrow means upregulated, down red arrow means downregulated.

Figure 2

Combined multi-omics to study wheat under heavy metal stress. (a) In all, 22 differentially expressed microRNAs (DEMs) and 1561 differentially expressed genes (DEGs) were identified in a low-Cd-accumulating wheat cultivar through small RNA and transcriptome sequencing. (b) Low-Fe stress significantly reduced the absorption of nutrients through ICP-MS-assisted ionomic analysis; 378 and 2619 DEGs were found in the shoots and roots of wheat under low-Fe conditions. (c) TaHMA2b-7A, an important Cd exporter regulating long-distance Cd translocation, was identified in wheat through combining ionomics, transcriptomics and functional gene analysis.

Figure 3

Functional genes that regulate heavy metal stress in wheat.

Figure 4

Combined method to investigate wheat plants in response to heavy metal stress. Epigenomics, transcriptomics, proteomics, metabolomics and ionomics are useful methods that can help us to clarify and analyze active regulatory networks regulating heavy metal stress responses and tolerance in wheat plants.