Banana fruit with nutritionally significant concentrations of iron and zinc: results from the field evaluation of genetically modified bananas ( Musa spp.) in Australia

Summary Iron deficiency remains a major public health problem in East Africa, where banana is a staple food for > 30 million people. This study investigated whether genetic modification could produce banana fruit containing nutritionally significant concentrations of iron while maintaining agronomic performance under field conditions. Six transgenes associated with iron homeostasis were expressed singly or in combination in Cavendish and Lady Finger bananas. In total, 450 genetically modified plants were field evaluated in Australia and fruit mineral concentrations assessed in the first planting crop. Elevated fruit iron and zinc concentrations, reaching 45.5 and 51.9 mg kg −1 dry weight, respectively, were associated with increased nicotianamine (NA) accumulation following expression of OsNAS . Iron concentrations sufficient to meet 50% of the estimated average requirement for children were achieved in 28 lines, with elevated NA suggesting improved iron bioavailability. Increased mineral accumulation negatively correlated with yield; however, this effect was partly mitigated by co‐expression of OsVIT1 . Early indicators of yield penalty included low corm iron, high leaf zinc concentrations and reduced photosynthetic efficiency. These findings demonstrate the potential of using genetic modification for the mineral biofortification of bananas in East Africa while highlighting factors that may assist in the early identification of high‐performing biofortified lines.