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Fig. 1 | Rice

Fig. 1

From: Comparison on cellular mechanisms of iron and cadmium accumulation in rice: prospects for cultivating Fe-rich but Cd-free rice

Fig. 1

Mechanisms of Fe/Cd uptake and translocation in rice. a Fe uptake from rhizosphere into root cells by specific root transporters. DMA is synthesized in cells and secreted into the rhizosphere by OsTOM1. DMA chelates rhizospheric Fe(III), forming Fe(III)-DMA complexes. Complexes are then taken up into root cells by OsYLS15. Roots also take up Fe(II) directly by metal transporters (OsIRT1/OsNRAMP1). b Cd is absorbed from rhizosphere into root cells mediated by OsIRT1 and OsNRAMP5. OsHMA3 plays a critical role in Cd compartmentalization into vacuoles in root cells. c Cd xylem loading in roots for translocation to shoots by OsHMA2, and Cd phloem loading for storage to grain sink. OsLCT1 and OsHMA2 mediate xylem-to-phloem transfer at nodes. d Fe xylem loading in roots for translocation to shoots and the remobilization of Fe through phloem from leaves for storage to grain sink. OsFRDL1, which is a citrate transporter localized at the root pericycle cells. OsFRDL1 loads citrate into the xylem and combines with Fe. ENA may be involved in efflux of NA into xylem. OsYSL2 then mediate Fe(II)-NA for phloem loading. OsTOM1 potentially participates in DMA transport, followed by mediating Fe(III)-DMA through OsYSL15. Furthermore, OsIRT1 directly transports Fe(II) in phloem companion cells of shoots. The encircled numerals represent the main localization of specific transporters. Right parts of the figure are adapted partially from Kobayashi et al. (2014) and Yoneyama et al. (2015)

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