title: Overexpression of MdbHLH104 gene enhances the tolerance to iron deficiency in apple.
abstract: Fe deficiency is a widespread nutritional disorder in plants. The basic helix-loop-helix (bHLH) transcription factors (TFs), especially Ib subgroup bHLH TFs which are involved in iron uptake, have been identified. In this study, an IVc subgroup bHLH TF MdbHLH104 was identified and characterized as a key component in the response to Fe deficiency in apple. The overexpression of the MdbHLH104 gene noticeably increased the H(+) -ATPase activity under iron limitation conditions and the tolerance to Fe deficiency in transgenic apple plants and calli. Further investigation showed that MdbHLH104 proteins bonded directly to the promoter of the MdAHA8 gene, thereby positively regulating its expression, the plasma membrane (PM) H(+) -ATPase activity and Fe uptake. Similarly, MdbHLH104 directly modulated the expression of three Fe-responsive bHLH genes, MdbHLH38, MdbHLH39 and MdPYE. In addition, MdbHLH104 interacted with 5 other IVc subgroup bHLH proteins to coregulate the expression of the MdAHA8 gene, the activity of PM H(+) -ATPase and the content of Fe in apple calli. Therefore, MdbHLH104 acts together with other apple bHLH TFs to regulate Fe uptake by modulating the expression of the MdAHA8 gene and the activity of PM H(+) -ATPase in apple.
authors.affiliation: National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China.
authors.forename: Yi-Ran
authors.initials: YR
authors.lastname: Ren
authors.affiliation: National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China.
authors.forename: Qing-Jie
authors.initials: QJ
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China.
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Yao
authors.affiliation: National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China.
authors.forename: Chun-Xiang
authors.initials: CX
authors.lastname: You
authors.affiliation: National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China.
authors.forename: Yu-Jin
authors.initials: YJ
authors.lastname: Hao
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007501:Iron / Q000378:metabolism*; D027845:Malus / Q000235:genetics* / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D007501:Iron
keywords: IVc subgroup bHLH transcription factor; apple; iron deficiency; iron uptake; plasma membrane H+-ATPase