Localisation of iron in wheat grain using high resolution secondary ion mass spectrometry

Insufficient iron (Fe) is one of the most prevalent micronutrient deficiencies in humans, with billions of people affected. Cereal grains are an important source of Fe for humans but the bioavailability of Fe in cereals is generally low. Information regarding the cellular and sub-cellular localisation of Fe in wheat grain will aid optimising nutrient delivery for human health. In this study high resolution secondary ion mass spectrometry (NanoSIMS) was used to map the distribution of Fe in the aleurone layer and in the endosperm of immature wheat grain. Iron was shown to be localised strongly in the phytin globoids in the aleurone cells and to a lesser extent in the cytoplasm around the starch granules in the endosperm.

► Fe deficiency is a major problem affecting billions of people.
► Cereals are an important source of Fe for humans but bioavalibility is low.
► Understanding where Fe is localised will aid optimisation of nutrient delivery.
► High resolution SIMS analysis was used to map Fe distributions in wheat grain.
► Fe was localised to phytate with a limited amount in the endosperm cytoplasm.