SLC13A4 and dietary heme iron intake measurement: Once in the vasculature, NA complexes are taken into the shoot via YSL transporters and ultimately reach the seed, and this transport is dependent on shoot expression of NAS4. In the absence of MYB10 and MYB72, NAS2 and NAS4 are not properly induced under iron deficiency, leading to local decreases in NA, decreased levels of NA bound Fe2+, and ultimately decreased levels of iron in the shoot and the seed.