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Genes involved in Fe acquisition are transcriptionally upregulated under conditions of Fe deficiency. MAs secreted to the rhizosphere via plasma membrane TOM transporters and the resulting Fe(III)?MAs complexes are taken up by roots through Fe(III)?MAs transporters (YSL15 and YSL16) in the plasma membrane. Rice takes up Fe from the rhizosphere using the ferrous Fe transporter IRT1, IRT2 and NRAMP1. YSL15 transports Fe(III)?DMA, but not Fe(II)?NA and Fe(III)?NA. YSL2 transports Fe(II)?NA but not Fe(III)?MAs. YSL18, a functional Fe(III)?DMA transporter that may be involved in DMA-mediated Fe distribution in the reproductive organs, lamina joints, and phloem cells at the base of the leaf sheath. IDEF1 and IDEF2 transcription factors are involved in activation of various genes of Fe acquisition; e.g., IRT1, YSl15 and YSL2. Rice plants translocate iron from the roots to old leaves mainly via xylem and to new leaves mainly via phloem (Kakei et al., 2012).
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