OsYSL18 is a rice iron(III)-deoxymugineic acid transporter specifically expressed in reproductive organs and phloem of lamina joints.
Iron uptake and translocation in plants are important processes for both plant and human nutrition, whereas relatively little is known about the molecular mechanisms of iron transport within the plant body. Several reports have shown that yellow stripe 1 (YS1) and YS1-like (YSL) transporters mediate metal-phytosiderophore uptake and/or metal-nicotianamine translocation. Among the 18 YSL genes in rice (OsYSLs), OsYSL18 is predicted to encode a polypeptide of 679 amino acids containing 13 putative transmembrane domains. An OsYSL18-green fluorescent protein (GFP) fusion was localized to the plasma membrane when transiently expressed in onion epidermal cells. Electrophysiological measurements using Xenopus laevis oocytes showed that OsYSL18 transports iron(III)-deoxymugineic acid, but not iron(II)-nicotianamine, zinc(II)-deoxymugineic acid, or zinc(II)-nicotianamine. Reverse transcriptase PCR analysis revealed more OsYSL18 transcripts in flowers than in shoots or roots. OsYSL18 promoter-beta-glucuronidase (GUS) analysis revealed that OsYSL18 was expressed in reproductive organs including the pollen tube. In vegetative organs, OsYSL18 was specifically expressed in lamina joints, the inner cortex of crown roots, and phloem parenchyma and companion cells at the basal part of every leaf sheath. These results suggest that OsYSL18 is an iron-phytosiderophore transporter involved in the translocation of iron in reproductive organs and phloem in joints.
Aoyama
Takahiro
T
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Kobayashi
Takanori
T
Takahashi
Michiko
M
Nagasaka
Seiji
S
Usuda
Kanako
K
Kakei
Yusuke
Y
Ishimaru
Yasuhiro
Y
Nakanishi
Hiromi
H
Mori
Satoshi
S
Nishizawa
Naoko K
NK
D000595:Amino Acid Sequence; D000818:Animals; D001383:Azetidinecarboxylic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001483:Base Sequence; D001693:Biological Transport, Active; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005290:Ferric Compounds / Q000378:metabolism*; D015870:Gene Expression; D017343:Genes, Plant; D066298:In Vitro Techniques; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism*; D052585:Phloem / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D017262:Siderophores / Q000235:genetics / Q000378:metabolism; D014018:Tissue Distribution; D014982:Xenopus laevis
D017931:DNA Primers; D005290:Ferric Compounds; D026901:Membrane Transport Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D017262:Siderophores; C082893:nicotianamine; D001383:Azetidinecarboxylic Acid; C052864:2'-deoxymugineic acid