# Heavy Metal-Associated (HMA) Domain-Containing Proteins: Insight into Their Features and Roles in Bread Wheat (Triticum aestivum L.)

## TL;DR

This study identifies and characterizes HMA genes in bread wheat, revealing their roles in plant growth, development, and stress responses.

## Contribution

The study provides a comprehensive analysis of HMA genes in bread wheat, including their distribution, evolution, and functional roles.

## Key findings

- 243 TaHMA genes were identified in bread wheat with distinct chromosomal localization and molecular profiles.
- Phylogenetic analysis grouped TaHMA proteins into five clades with variable sub-cellular localization.
- Gene duplication and synteny analysis suggest evolutionary expansion and relatedness to Arabidopsis and rice.

## Abstract

Unprecedented economic growth has resulted in the booming of industries, which in turn has led to rapidly growing heavy metal pollution. Heavy metals have a detrimental effect on plants and animals through the contamination of air, food, and water resources, thereby posing a major environmental and health concern for people across the world. The heavy metal ATPases (HMAs) participate in the absorption and transportation of the otherwise essential metal ions within the living cell, while sequestering the harmful effects of non-essential heavy metal ions. The present study aimed to identify and annotate the complete set of HMA genes and proteins in a major food crop, such as bread wheat. The results revealed an array of diverse characteristics, such as a wide distribution of the HMAs within the cell, while the evolutionary studies pointed out the relatedness of the identified members with other plant species. Overall, the study revealed the role played by these genes in mediating crucial biological processes, such as plant growth, development, and stress responses.

The heavy metal-associated (HMA) domain-harboring proteins constitute critical players involved in the transport of various metal ions in plants, and are associated with development and stress responses. Herein, a total of 243 TaHMA genes were identified in the bread wheat genome, each of which had a characteristic molecular profile and a distinct chromosomal localization. The TaHMA proteins were distributed in five clades in phylogeny, which differed with respect to the distribution of the key HMA domain. Sub-cellular localization was variable for the TaHMA proteins. Gene structure analysis yielded similar results when compared with the orthologous counterparts. Cis-regulatory element analysis produced a range of promoter elements, suggesting their diverse biological roles. Gene duplication analysis revealed a crucial role played by tandem and segmental duplication events in the expansion of TaHMA genes. Synteny analysis highlighted the evolutionary relatedness of TaHMA genes with those derived from Arabidopsis and rice. Expression analysis provided crucial information about the role of TaHMAs in mediating vital responses in the plant body, including the development of tissues and the regulation of various abiotic stress conditions. Overall, the study provides significant cues and evidence to functionally annotate and characterize the differentially expressed TaHMAs in order to validate their role.