AUTHOR=Wang Yu , Zhang Xuemeng , Yan Yuhan , Niu Tingting , Zhang Miao , Fan Chao , Liang Wenwei , Shu Yongjun , Guo Changhong , Guo Donglin , Bi Yingdong TITLE=GmABCG5, an ATP-binding cassette G transporter gene, is involved in the iron deficiency response in soybean JOURNAL=Frontiers in Plant Science VOLUME=Volume 14 - 2023 YEAR=2024 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1289801 DOI=10.3389/fpls.2023.1289801 ISSN=1664-462X ABSTRACT=Iron deficiency is a major nutritional problem causing iron deficiency chlorosis (IDC) and yield reduction in soybean, one of the most important crops. The ATP-binding cassette G subfamily plays a crucial role in material transportation in plants. In this study, we cloned the GmABCG5 gene from soybean and verified the role of GmABCG5 in Fe homeostasis. Analysis showed that the GmABCG5 belonged to the ABCG subfamily and was subcellular localized at the cell membrane. The GmABCG5 expression from high to low was stem, root, and leaf of young soybean seedlings; and the order of expression was flower, pod, seed stem, root, and leaf in mature soybean plants. The GUS assay and qRT-PCR results showed that the GmABCG5 expression was induced by iron deficiency, significantly in the leaf. We obtained the GmABCG5 overexpressed and repressed soybean hairy root complexes. The overexpression of GmABCG5 promoted and inhibition of GmABCG5 retarded the growth of soybean hairy roots, independent of iron nutritious condition, confirming the growth-promotion function of GmABCG5. Iron deficiency has a negative effect on the growth of soybean complexes which was more obvious in the GmABCG5 inhibition complexes. The chlorophyll content was increased in the GmABCG5 overexpression complexes and decreased in the GmABCG5 inhibition complexes. Iron deficiency treatment widened the gap in the chlorophyll contents. The FCR activity was induced by iron deficiency and showed an extraordinary increase in the GmABCG5 overexpression complexes, accompanied by the most Fe accumulation. The antioxidant capacity was enhanced when GmABCG5 was overexpressed while reduced when GmABCG5 was inhibited under iron deficiency. These results showed that the response mechanism to iron deficiency is more actively mobilized in GmABCG5 overexpression seedlings. Our results indicated that GmABCG5 could improve the plant's tolerance to iron deficiency, suggesting that GmABCG5 might have the function of Fe mobilization and redistribution and/or secretion of Fe substances in plants. The findings provide new insight into the ABCG subfamily genes in the regulation of iron homeostasis of plants.