title: Iron deficiency regulated OsOPT7 is essential for iron homeostasis in rice.
abstract: The molecular mechanism of iron (Fe) uptake and transport in plants are well-characterized; however, many components of Fe homeostasis remain unclear. We cloned iron-deficiency-regulated oligopeptide transporter 7 (OsOPT7) from rice. OsOPT7 localized to the plasma membrane and did not transport Fe(III)-DMA or Fe(II)-NA and GSH in Xenopus laevis oocytes. Furthermore OsOPT7 did not complement the growth of yeast fet3fet4 mutant. OsOPT7 was specifically upregulated in response to Fe-deficiency. Promoter GUS analysis revealed that OsOPT7 expresses in root tips, root vascular tissue and shoots as well as during seed development. Microarray analysis of OsOPT7 knockout 1 (opt7-1) revealed the upregulation of Fe-deficiency-responsive genes in plants grown under Fe-sufficient conditions, despite the high Fe and ferritin concentrations in shoot tissue indicating that Fe may not be available for physiological functions. Plants overexpressing OsOPT7 do not exhibit any phenotype and do not accumulate more Fe compared to wild type plants. These results indicate that OsOPT7 may be involved in Fe transport in rice.
authors.affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
authors.forename: Khurram
authors.initials: K
authors.lastname: Bashir
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ishimaru
authors.forename: Reiko Nakanishi
authors.initials: RN
authors.lastname: Itai
authors.forename: Takeshi
authors.initials: T
authors.lastname: Senoura
authors.forename: Michiko
authors.initials: M
authors.lastname: Takahashi
authors.forename: Gynheung
authors.initials: G
authors.lastname: An
authors.forename: Takaya
authors.initials: T
authors.lastname: Oikawa
authors.forename: Minoru
authors.initials: M
authors.lastname: Ueda
authors.forename: Aiko
authors.initials: A
authors.lastname: Sato
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Uozumi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Naoko K
authors.initials: NK
authors.lastname: Nishizawa
mesh_terms: D000818:Animals; D001681:Biological Assay; D005293:Ferritins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D005966:Glucuronidase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006706:Homeostasis; D007501:Iron / Q000378:metabolism; D000090463:Iron Deficiencies; D018977:Micronutrients / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D009865:Oocytes / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D021381:Protein Transport; D013312:Stress, Physiological / Q000235:genetics; D013347:Subcellular Fractions / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D018977:Micronutrients; D010940:Plant Proteins; D005293:Ferritins; D007501:Iron; D005966:Glucuronidase; D005978:Glutathione