Rice metal-nicotianamine transporter, OsYSL2, is required for the long-distance transport of iron and manganese.
Rice (Oryza sativa) is indispensable in the diet of most of the world's population. Thus, it is an important target in which to alter iron (Fe) uptake and homeostasis, so as to increase Fe accumulation in the grain. We previously isolated OsYSL2, a functional iron [Fe(II)]- and manganese [Mn(II)]-nicotianamine complex transporter that is expressed in phloem cells and developing seeds. We produced RNAi (OsYSL2i) and overexpression lines (OXOsYSL2) of OsYSL2. At the vegetative stage in an OsYSL2i line, the Fe and Mn concentrations were decreased in the shoots, and the Fe concentration was increased in the roots. At the reproductive stage, positron-emitting tracer imaging system analysis revealed that Fe translocation to the shoots and seeds was suppressed in OsYSL2i. The Fe and Mn concentrations were decreased in the seeds of OsYSL2i, especially in the endosperm. Moreover, the Fe concentration in OXOsYSL2 was lower in the seeds and shoots, but higher in the roots, compared with the wild type. Furthermore, when OsYSL2 expression was driven by the sucrose transporter promoter, the Fe concentration in the polished rice was up to 4.4-fold higher compared with the wild type. These results indicate that the altered expression of OsYSL2 changes the localization of Fe, and that OsYSL2 is a critical Fe-nicotianamine transporter important for Fe translocation, especially in the shoots and endosperm.
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Yasuhiro
Y
Ishimaru
Hiroshi
H
Masuda
Khurram
K
Bashir
Haruhiko
H
Inoue
Takashi
T
Tsukamoto
Michiko
M
Takahashi
Hiromi
H
Nakanishi
Naohiro
N
Aoki
Tatsuro
T
Hirose
Ryu
R
Ohsugi
Naoko K
NK
Nishizawa
D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D056625:Endosperm / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018520:Plant Shoots / Q000378:metabolism; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics
D027682:Cation Transport Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D008345:Manganese; D007501:Iron