MaizeNutriUp: a holistic assessment of combined iron, zinc and selenium accumulation and translocation from root to shoot to grain under water limitation in maize

• Applicant: Thomas Alcock, Ph.D.
• Subject Area: Plant Cultivation, Plant Nutrition, Agricultural Technology ; Plant Physiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555456916

Over 1.2 billion people worldwide suffer from deficiencies in one or more of iron (Fe), zinc (Zn) and selenium (Se). Globally, maize (Zea mays L.) has the highest total production among grains, but people relying on maize-based diets are among those most at risk of dietary deficiencies of these mineral nutrients. Meanwhile, projected increased incidences of climate-change induced water limitation are predicted to result in a reduction in both maize grain yield and micronutrient accumulation. Breeding for more resilient Fe, Zn and Se uptake and efficient translocation of these nutrients to edible tissue under water limitation represents an encouraging strategy to increase dietary micronutrient consumption. This is reliant on building a holistic overview of nutrient uptake and accumulation processes at the whole-plant level. This research programme will leverage maize genotypes mutated in genes controlling nutrient uptake and accumulation processes along with diverse germplasm originating from breeding backgrounds. This will enable identification of physiological, molecular and genetic factors controlling combined Fe, Zn and Se accumulation under water limitation, as well as lines and trait combinations suitable for entering breeding programmes aimed at increasing maize nutrient quality. Work packages will combine advanced multi-omics techniques spanning ionomics, genomics and transcriptomics, and state of the art X-ray-enabled elemental spatial distribution mapping to understand spatiotemporal nutrient uptake and translocation dynamics. One objective is to identify molecular mechanisms controlling the uptake of Fe, Zn and Se in root-uptake “hotspots”. This will particularly focus on the role of exo- and endodermal barriers, which respond to exogenous water and nutrient conditions to optimise both uptake and retention, but whose importance for micronutrient uptake in maize has not yet been explored. These findings will be complemented by characterisation of the responsiveness of root, shoot and inflorescence transporter expression to Fe, Zn, Se and water supply between diverse genotypes and their roles in cell import and export, root radial transport, and xylem and phloem loading. Finally, novel candidate genes for increased Fe, Zn and Se accumulation under water limitation will be identified. This will employ both RNA-sequencing to detect variation in transcriptional responses to exogenous water and nutrient supply, and a screen of a maize multiparent advanced generation inter-crossing (MAGIC) population segregating for tolerance to water limitation coupled with mapping of genetic loci associated with shoot and grain Fe, Zn and Se accumulation in both glasshouse and field conditions. Taken in isolation and together as a whole, the work packages of this research programme will contribute an advanced understanding of Fe, Zn and Se uptake and accumulation processes in maize for breeding for increased nutritional value in future growth scenarios.

• DFG Programme: Emmy Noether Independent Junior Research Groups