Metal Tolerance Protein Encoding Gene Family in Fagopyrum tartaricum: Genome-Wide Identification, Characterization and Expression under Multiple Metal Stresses

Metal tolerance proteins (MTP) as divalent cation transporters are essential for plant metal tolerance and homeostasis. However, the characterization and the definitive phylogeny of the MTP gene family in Fagopyrum tartaricum, and their roles in response to metal stress are still unknown. In the present study, MTP genes in Fagopyrum tartaricum were identified, and their phylogenetic relationships, structural characteristics, physicochemical parameters, as well as expression profiles under five metal stresses including Fe, Mn, Cu, Zn, and Cd were also investigated. Phylogenetic relationship analysis showed that 12 Fagopyrum tartaricum MTP genes were classified into three major clusters and seven groups. All FtMTPs had typical structural features of the MTP gene family and were predicted to be located in the cell vacuole. The upstream region of FtMTPs contained abundant cis-acting elements, implying their functions in development progress and stress response. Tissue-specific expression analysis results indicated the regulation of FtMTPs in the growth and development of Fagopyrum tataricum. Besides, the expression of most FtMTP genes could be induced by multiple metals and showed different expression patterns under at least two metal stresses. These findings provide useful information for the research of the metal tolerance mechanism and genetic improvement of Fagopyrum tataricum.