Iron is one of the most limiting factors for biomass production in plants. Iron deficiency results in severe chlorosis as well as reduced productivity and quality of crops. Since plants are the major source for iron in human nutrition, iron deficiency in crops has not only agronomical and economical impact but also affects human iron deficiency, one of today’s most prevalent nutritional problems. Due to the high iron requirement of the  photosynthetic machinery, chloroplasts, the site of oxygenic photosynthesis in plants, are strong intracellular sinks for iron.

Thus, iron transport and storage processes in chloroplasts represent bottlenecks controlling iron homeostasis at the cellular level. Molecular targets balancing iron homeostasis in chloroplasts, however, are still unknown, although they might limit plant growth and productivity under iron deficiency or toxicity. The objective of this proposal is to uncover regulatory processes linking iron homoeostasis in the chloroplast and the cytosol of plant cells with mechanisms of iron acquisition and transport. In a genome- and proteome-wide approach, molecular targets in response to iron deficiency or toxicity will be identified in the model plantArabidopsis thaliana. Results gained in the model plant will be used to modify and improve growth conditions as well as productivity of agronomical relevant crop species.

The work plan is focussing on three specific aims: (i) Characterisation of chloroplast and intracellular iron transport and storage pathways. (ii) Identification of key components controlling plastid and cellular iron homeostasis as well as plant development and yield formation under iron stress. (iii) Iron homeostasis in agronomical relevant annual crop species and fruit trees under iron deficiency and re-supply.

We expect to: (i) Identify new iron transport and storage pathways and components, regulating chloroplast and cellular iron homeostasis. (ii) Describe the impact of these key players in plant iron homeostasis on growth and productivity. (iii) Develop new strategies to improve growth and productivity of crop plants under iron deficiency and re-supply. Research will include studies on the genomic, transcript, protein and metabolite level. Furthermore, the project is complemented by functional analysis of transport proteins. Finally, all results merge in the study of the physiological response of model and agronomical relevant plants under iron deficiency or resupply and the development and application of new compounds to correct iron deficiency symptoms in plants.

Our multidisciplinary project within the transnational PLANT-KBBE programme is based on the collaboration of academic research as well as the development and application of results and methods in industry. In line with the goals of the PLANT-KBBE call we aim to transfer knowledge from model plants to agronomical relevant crop species by integrating combined information provided by novel technologies and genome wide analyses.

The work plan of HOT IRON – PLANT PROGROW is supported by four academic, one private partner and a private subcontractor representing scientific expertise from Germany, France, and Spain. We expect that by covering the entire spectrum of methods in modern plant biology we will be able to gain fundamental insights into the genome-wide regulation of intracellular iron homeostasis and transport processes, and thereby provide knowledge-based support to European bio-economy. Thus, our project should serve as a starting point for safely balancing plant cellular iron content as well as to produce iron fortified crops to improve human nutrition. Understanding the role of intracellular iron homeostasis and transport pathways is a key determinant in the success of such efforts.