Genome-Wide Identification and Expression Analysis of Metal Tolerance Protein Gene Family in Medicago truncatula Under a Broad Range of Heavy Metal Stress

作者：Ahmed H. El‐Sappah, Rania G. Elbaiomy, Ahmed S. Elrys, Yu Wang, Yumin Zhu, Qiulan Huang, Kuan Yan, Zhao Xianming, Manzar Abbas, Khaled A. El‐Tarabily, Jia Li · 发表于：Frontiers in Genetics · 年份：2021 · DOI：10.3389/fgene.2021.713224 · 被引用次数：42 · 研究领域：Plant Micronutrient Interactions and Effects、Trace Elements in Health、Plant Stress Responses and Tolerance

Metal tolerance proteins (MTPs) encompass plant membrane divalent cation transporters to specifically participate in heavy metal stress resistance and mineral acquisition. However, the molecular behaviors and biological functions of this family in Medicago truncatula are scarcely known. A total of 12 potential MTP candidate genes in the M. truncatula genome were successfully identified and analyzed for a phylogenetic relationship, chromosomal distributions, gene structures, docking analysis, gene ontology, and previous gene expression. M. truncatula MTPs ( MtMTPs ) were further classified into three major cation diffusion facilitator (CDFs) groups: Mn-CDFs, Zn-CDFs, and Fe/Zn-CDFs. The structural analysis of MtMTPs displayed high gene similarity within the same group where all of them have cation_efflux domain or ZT_dimer. Cis -acting element analysis suggested that various abiotic stresses and phytohormones could induce the most MtMTP gene transcripts. Among all MTPs , PF16916 is the specific domain, whereas GLY, ILE, LEU, MET, ALA, SER, THR, VAL, ASN, and PHE amino acids were predicted to be the binding residues in the ligand-binding site of all these proteins. RNA-seq and gene ontology analysis revealed the significant role of MTP genes in the growth and development of M. truncatula . MtMTP genes displayed differential responses in plant leaves, stems, and roots under five divalent heavy metals (Cd 2+ , Co 2+ , Mn 2+ , Zn 2+ , and Fe 2+ ). Ten, seven, and nine MtMTPs respo...