title: A Golgi-localized MATE transporter mediates iron homoeostasis under osmotic stress in Arabidopsis.
abstract: Iron is an essential micronutrient that acts as a cofactor in a wide variety of pivotal metabolic processes, such as the electron transport chain of respiration, photosynthesis and redox reactions, in plants. However, its overload exceeding the cellular capacity of iron binding and storage is potentially toxic to plant cells by causing oxidative stress and cell death. Consequently, plants have developed versatile mechanisms to maintain iron homoeostasis. Organismal iron content is tightly regulated at the steps of uptake, translocation and compartmentalization. Whereas iron uptake is fairly well understood at the cellular and organismal levels, intracellular and intercellular transport is only poorly understood. In the present study, we show that a MATE (multidrug and toxic compound extrusion) transporter, designated BCD1 (BUSH-AND-CHLOROTIC-DWARF 1), contributes to iron homoeostasis during stress responses and senescence in Arabidopsis. The BCD1 gene is induced by excessive iron, but repressed by iron deficiency. It is also induced by cellular and tissue damage occurring under osmotic stress. The activation-tagged mutant bcd1-1D exhibits leaf chlorosis, a typical symptom of iron deficiency. The chlorotic lesion of the mutant was partially recovered by iron feeding. Whereas the bcd1-1D mutant accumulated a lower amount of iron, the iron level was elevated in the knockout mutant bcd1-1. The BCD1 protein is localized to the Golgi complex. We propose that the BCD1 transporter plays a role in sustaining iron homoeostasis by reallocating excess iron released from stress-induced cellular damage.
authors.affiliation: Department of Chemistry, Seoul National University, Korea.
authors.forename: Pil Joon
authors.initials: PJ
authors.lastname: Seo
authors.forename: Jungmin
authors.initials: J
authors.lastname: Park
authors.forename: Mi-Jeong
authors.initials: MJ
authors.lastname: Park
authors.forename: Youn-Sung
authors.initials: YS
authors.lastname: Kim
authors.forename: Sang-Gyu
authors.initials: SG
authors.lastname: Kim
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Jung
authors.forename: Chung-Mo
authors.initials: CM
authors.lastname: Park
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D006056:Golgi Apparatus / Q000378:metabolism*; D006706:Homeostasis; D007501:Iron / Q000378:metabolism*; D027701:Organic Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009995:Osmosis / Q000502:physiology; D018515:Plant Leaves / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D027701:Organic Cation Transport Proteins; D007501:Iron