Korean Journal of Breeding Science :eISSN 2287-5174 / pISSN 0250-3360

Fig. 2.

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Physiological processes and genes involved in uptake, transport and storage of Zn and Fe in strategy I and strategy II for biofortification from Gupta et al. (2021). Free Zn2+ and phytosiderophore (PS)-bound Zn/Fe are acquired from the soil (rhizosphere) by the root epidermal cells. Zn and Fe move via the apoplast and symplast to the pericycle, via cortex and endodermis, but may be sequestered in vacuoles (V) in endodermis cells. Zn and Fe are loaded into the xylem and transferred into the phloem in the root. Later, these are transferred to basal shoot or leaf tissues (not shown). Zn and Fe from leaf cell plastids (P) and vacuoles (V) are remobilized and loaded into the phloem for transport to the ear. After uptake into the aleurone layer, most Zn and Fe are sequestered in protein storage vacuoles (PSVs) bound to phytate (Phy). A small proportion of Zn and Fe may enter the endosperm and be stored there with ferritin (Fer) in amyloplasts (A). ZIP=ZRT-IRT-like protein, YSL=yellow-stripe-like transporter, NRAMP=natural resistance-associated macrophage protein, VIT=vacuolar iron transporter, NAS=nicotianamine synthase; NAAT=nicotianamine aminotransferase; TOM=transporter of mugineic acid; IRT=iron-regulated transporter; NA=nicotianamine.
Korean J. Breed. Sci. 2023;55:325-49 https://doi.org/10.9787/KJBS.2023.55.4.325
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