Genome-wide identification and characterization of the metal tolerance protein (MTP) genefamily in Eucalyptus grandis

Metal tolerance proteins (MTPs) play an important role in the transport of metals at the cellular, tissue andwhole plant levels. Considering the limited information on the MTP gene family in Eucalyptus plants whichhave phytoremediation properties and their different roles, this study aimed to identify the members, proteincharacteristics, simple sequence repeats (SSR) markers, miRNAs targets and gene expression analysis of thisgene family by bioinformatics tools. The twenty MTP gene members were identified in the genome ofEucalyptus. The phylogenetic tree displayed that MTPs were categorized into three groups (Mn-MTP, Zn/Fe-MTP, and Zn-MTP) and seven sub-groups and were predicted to be localized in vacuoles. EqMTP proteinswere predicted to encode polypeptides of ۳۱۵-۸۸۴ amino acids with molecular weights ranging from ۳۶.۰۷to ۹۷.۳۲ kDa. Fifty-seven SSRs were identified in ۱۸ MTP sequences and most of the genes had a singleSSR. Identification of the simple sequence repeats (SSRs) marker of this family was found to be helpful inselecting the associated marker. Prediction of MTPs-targeted miRNAs, illustratd ۱۴ EqMTP genes wastargeted for ۳۶ miRNAs. All the genes were suppressed by at least more than one miRNA, except forEqMTP۹.۱. EqMTP۱۲ and EqMTP۸.۲ were suppressed by eight and seven miRNAs, respectively. Manymetabolic pathways and activities related to plant growth and development, signal transduction, and reactionto stresses (including heavy metals) can be arranged by miRNAs. EqMTP۱۱ gene expression was increcedin various developmental stages and biotic stresses in different Eucalyptus species. The EqMTP۱۱ gene wasproposed as a good candidate for genetic engineering and breeding programs in order to introduce a metaltolerantcultivar.

Keywords:

Cation diffusion facilitator , Eucalyptus , Heavy metals , Phytoremediation , Metal tolerance protein