Comprehensive characterization of HMA transporters in common bean: Tissue‐specific expression and response to metal stress

Plant growth and development require tightly regulated concentration of heavy metal ions, which function as essential nutrients. In this context, the P1B‐heavy metal ATPase (HMA), also known as the HMA family, is critical for mediating metal ion uptake, root‐to‐shoot translocation, and vacuolar sequestration in plants. This study presents a comprehensive characterization of 11 HMA genes in Phaseolus vulgaris L. ( PvHMA ). Phylogenetic analysis classified the PvHMAs genes into six distinct clusters, supported by conserved gene structure and motif distributions. PvHMA1 , ‐2 , ‐5 , ‐6 , ‐7 , and ‐11 exhibited widespread expression across multiple tissues and harbored a diverse array of cis‐regulatory elements in their promoter, suggesting multiple roles in plant growth and development. In contrast, PvHMA3 and PvHMA8 displayed tissue‐specific expression patterns, being predominantly expressed in roots and leaves, respectively. Under zinc stress, PvHMA1 , localized in chloroplasts, showed marked upregulation in shoot tissue. Notably, this transcriptional response was not observed under copper exposure, despite the high structural similarity between PvHMA1 and its Arabidopsis thaliana homolog, AtHMA1 (where AtHMA is Arabidopsis thaliana HMA). PvHMA2 , an ortholog of the A. thaliana HMA2/4, exhibited increased sensitivity to cobalt stress. Additionally, PvHMA5 and ‐ 11 were differentially expressed in shoots in response to zinc treatment. Collectively, these findings provide a detailed overview of the HMA family in P. vulgaris and reveal a complex regulatory network of transporters involved in heavy metal homeostasis, with implications for plant nutrition, development, and stress responses.