The rationale of our research

Metal micronutrients essential for plants (Fe, Mn, Cu, Zn, Ni and Mo) have unique chemical properties whose exploitation expands the range of biochemical transformations catalyzed in a cell. Micronutrients can also become toxic. Hence, plants must carefully regulate intracellular micronutrient levels within a remarkably narrow range of physiological concentrations. In the last decades, impressive increases in crop yield have been achieved with the adoption of intensive farming techniques. However, the extended use of mineral-based macronutrient fertilizers, continuous cropping, intensive irrigation, pesticides, and high-yielding varieties has led to a situation where crop micronutrient demands often exceed soil micronutrient availability. Nowadays, micronutrient deficiencies are common worldwide and must be prevented or treated to sustain yield. Furthermore, these agricultural practices focused on crop yield have concomitantly produced a continuous fall in the nutritional quality of plant-based food. This fact has contributed to human micronutrient malnutrition (‘hidden hunger’), affecting ~30% of the human population. Iron and Zn are the most widespread deficiencies and lead to severe outcomes such as neuropsychologic impairment and perinatal complications. Micronutrient malnutrition may further threaten future generations since recent research has shown that elevated atmospheric CO₂ concentrations can decrease Fe and Zn levels of staple crops. Maintaining yields and increasing the nutritional quality of foods in a changing environment need a wholistic and knowledge-based transformation of agricultural practices and breeding programs.

The root metabolome of metal-stressed crops

A significant part of plant's adaptation to stress is the production and secretion by roots of an array of metabolites with diverse functions. Once in the rhizosphere, metabolites secreted by plants can directly mine metals from the soil, as well as attract, repel, inhibit or kill existing biota. We are interested in discovering, studying and exploiting this limitless portfolio of substances. Currently, we combine metabolomics, its sub-fields exo-metabolomics and computational metabolomics, along with transcriptomics to decipher poorly known metabolic networks occurring in roots of Fe- and Zn- deficient crop plants, capturing the chemical diversity of metabolites crops release into the rhizosphere.  Using ectopic transient expression and enzymatic assays, we tackle the identification of enzymes responsible for the production of metabolites of interest. Furthermore, we study the interplay between root exudates and root cell walls, soil components and root microbiome.

Tuning iron homeostasis in plants

The team is interested in understanding how plants finely regulate the balance between micronutrient acquisition, distribution and toxicity, with the final goal of increasing micronutrient content in crops. On the one hand, we are studying molecular basis controlling the class of metabolite produced and released by different crops to cope with low Fe availability, finding the DNA signatures and the specific components of the Fe-homeostasis regulatory cascade in plants controlling such metabolite production. On the other hand, we are interested in BTS/L proteins, key players in fine-tuning the balance between Fe acquisition and Fe supply by facilitating the ubiquitination and turnover of specific proteins. Despite the importance of protein turnover, a comprehensive analysis of this layer of regulation in Fe homeostasis in plants is still lacking. We are working on identifying the majority of the proteins ubiquitinated by the BTS/L regulon to understand their impact on the Fe deficiency response in the model plant Arabidopsis thaliana.