Abstract:
Metal tolerance protein (MTP), also known as cation diffusion facilitator (CDF), is a metal ion transport-related protein. To study the sequence characteristics and evolutionary relationships of the
MTP gene family in
Amaranthus hypochondriacus L., and to predict the functions and regulatory mechanisms of its members, we took the latest
A. hypochondriacus genome as a reference and identified a total of nine members of the
A. hypochondriacus MTP family. According to their sequence characteristics, they were divided into three subgroups: Zn-CDF (3), Zn/Fe-CDF (4), and Mn-CDF (4). All family members contained a cation_efflux domain, a typical feature of MTP transporters, with some also containing a ZT_dimer domain. Chromosome mapping showed that the nine
MTP genes were distributed on seven chromosomes. Under cadmium (Cd) stress, the expression levels of
AhMTP7 and
AhMTP9 were inhibited in both leaves and roots, while the expression level of
AhMTP6 was inhibited in leaves but induced in roots. The expression levels of the other six
AhMTPs were induced by Cd, with
AhMTP2 and
AhMTP3 only induced in leaves, and
AhMTP5 only induced in roots. Promoter cis-acting element analysis identified several cis-acting elements in the
AhMTP promoter for stress response, growth and development, and hormone signaling. MicroRNA (miRNA) prediction analysis showed that 15 miRNAs targeted seven
AhMTPs.