Abstract:In the present study, a pair of homologous genes BrrHMA2.1 (GenBank is MG_283237) and BrrHMA2.2 (GenBank is MG_283238) of the heavy metal ATPase (HMA) family in turnip (Brassica rapa var. rapa) was cloned and their protein sequence characteristics and gene expression patterns were analyzed. (1) The fulllength open reading frames of these two genes were 2 619 and 2 724 bp and they encoded 872 and 907 amino acids, respectively. Sequence structure analysis showed that both BrrHMA2.1 and BrrHMA2.2 proteins included six transmembrane regions and conserved domains of HMA family. Phylogenetic tree analysis showed that BrrHMA2.1 and BrrHMA2.2 proteins had the closest evolutionary homology with AtHMA2. (2) The results of subcellular localization indicated that both BrrHMA2.1 and BrrHMA2.2 proteins were localized in the plasma membrane. (3) qRTPCR analysis showed that the expression levels of BrrHMA2.1 and BrrHMA2.2 genes were much higher in leaves at the early stage of turnip. However, the expression levels of these two genes in leaves gradually decreased whereas those in roots gradually increased with the increasing growth time. In addition, the results also found that BrrHMA2.1 gene was induced by Cd2+, Zn2+, Na+ and Mg2+ while BrrHMA2.2 gene was induced by Cd2+, Na+ and Cu2+ stresses, indicating these two genes may play roles in coping with these metal ions. This study provides foundation for further functional studies on plant HMA genes in heavy metal tolerance or transport.