Fig. 3: Transport of synthetic DMA analogs.

a Structures of synthetic DMA analogs. b Addition of 50 μM ⁵⁵Fe(III)-DMA and ⁵⁵Fe(III)-proline deoxymugineic acid (PDMA) to HvYS1-expressing Sf9 insect cells (1 × 10⁷) enhanced their Fe(III)-transport activity. In contrast, ⁵⁵Fe(III)-GDMA and ⁵⁵Fe(III)-MGDMA only marginally enhanced the Fe(III)-transport activities of the cells. Each Fe(III) complex contained 10 mol% radioactive ⁵⁵Fe. Sf9 insect cells transfected with empty vector were used as a control. Values are means with standard deviations of the four cell lysate replications (two-tailed t-test for Fe(III)-PDMA in HvYS1). c Fe(III)-transporting activities of synthetic DMA and PDMA in Xenopus oocytes injected with HvYS1, OsYSL15, or ZmYS1 cRNA, or water (negative control) were measured by two-electrode voltage clamp analysis. Values are means with standard deviations of the four replicates (two-tailed t-test for water injection). d Detection of PDMA derivatized using 9-fluorenylmethoxycarbonyl chloride (FMOC) by liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS) analysis in the xylem sap of rice plants supplied with Fe-DMA and Fe-PDMA in the nutrient solution. DMA 2′-deoxymugineic acid, PDMA proline-2′-deoxymugineic acid, GDMA glycine-2′-deoxymugineic acid, MGDMA N-methylglycine-2′-deoxymugineic acid, HvYS1 Hordeum Vulgare yellow stripe 1, OsYSL15 Oryza Sativa yellow stripe 1 like transporter 15, ZmYS1 Zea mays yellow stripe 1.