Genome-wide identification of the ABC gene family in sweet potato and its expression profiles in response to iron, aluminum, zinc, and copper stresses

ATP-binding cassette ( ABC ) transporters constitute one of the largest gene families in plants. These encoded transmembrane proteins rely on energy provided by ATP hydrolysis to facilitate the directional transport of diverse substrates, such as heavy metal (HM) ions, secondary metabolites, and phytohormones, playing a pivotal role in plant responses to HM stress. In this study, a systematic identification and expression analysis of the ABC gene family in sweet potato ( Ipomoea batatas ) was conducted at the whole-genome level. We comprehensively characterized the physicochemical properties, structural features, chromosomal distribution, and tissue-specific expression patterns of IbABC genes. Furthermore, their expression profiles under iron (Fe), aluminum (Al), zinc (Zn), and copper (Cu) stress were evaluated using RT-qPCR. The results demonstrated that most IbABC genes exhibited significant differential expression under HM stress. Notably, IbABCC14 was significantly upregulated under all four metal treatments (Fe, Al, Zn, and Cu) and showed high homology with phytochelatin transporters in Arabidopsis thaliana and Oryza sativa . This suggests that IbABCC14 may participate in HM detoxification by mediating vacuolar sequestration. By elucidating the expression patterns of the IbABC family under HM stress, this study identifies key candidate genes for breeding sweet potato varieties with enhanced HM tolerance.