National and international active projects funded to our team refer to the following topics:

• the role of root iron plaques in saline soils - IPSALS project
• the role of iron plaques in plant nutrition and its interaction with soil components (in collaboration with the Universities of Turin and Bari) - ROOTARMOUR project

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Funded by the Ministry of University and Research, Internationalization Research Department

Mission 4, "Education and Research" - Component 2, "From Research to Business", Investment 1.2, “Funding projects presented by young researchers”

PI: E. Pellegrini

IPSALS focuses on promising novel functions of the so-called root iron plaques. Plaques are iron (Fe) and manganese (Mn) depositions on root surfaces of wetland plants, formed by the diffusion of oxygen from roots to the anoxic flooded soil. Root radial oxygen loss (ROL) triggers the oxidation of the reduced Fe in the rhizosphere, which consequently precipitates forming reddish-brown coatings on root surface. Environmental conditions favouring plaque formation would interest large land surfaces in the near future, due to the sea level rise forecasted as a consequence of climate change, with coastal areas more prone to floods and soil salinization. Crops potentially able to develop plaques are a promising prospect to contrast the loss of cultivated land. Moreover, new strategies of land management enhancing this trait could possibly reinforce the resilience of both agricultural and wild habitats. Evidences on plaque functions towards floods and soil salinization are currently inadequate. Plaques were only marginally investigated as a flood-tolerant trait and were never considered as a plant strategy to cope with salt stress. The IPSALS project aims to shed light on possible novel functions of plaques, including their potential applicability in sustainable agriculture. Major scientific questions are: i) can plaques reduce salt stress in plants? ii) are crops capable to develop this trait? and iii) which are the consequences for plant nutrition? The hypotheses are that plaques can physically act as a shield towards salt intrusion and that crops showing adequate ROL can develop plaques. Moreover, plaques can regulate Fe and Mn uptake in plants, and be a secondary source of possible immobilized nutrients within the plaque structure (e.g. phosphorous). The project relies on advanced imaging techniques (planar optodes) and innovative methods (microsensors) to monitor temporal and spatial changes of oxygen, plaques and nutrients at the soil-plaque and plaque-root interfaces.

Conceptual model of plaque functions at the root-rhizosphere interface. Root ROL rates drive the deposition of Fe and Mn on root surfaces, which potentially protect roots from salt intrusion (Na⁺/Cl^-) and mediate nutrient uptake (e.g. Fe²⁺, Mn²⁺ and PO₄^3-)

PRIN project, call 2022

Project official webpage: https://www.raer.unito.it/projects/rootarmour

The project is being implemented thanks to the funding by the Italian Ministry for University and Research (MUR), starting from November, 1st 2023 and will last for two years. The partnership involves researchers from the University of Torino (UniTO), the University of Udine (UniUD) and the University of Bari (UniBA).

Wetlands are complex ecosystems having important functions that are driven by many physical, chemical, and biological processes with implications at local, regional and global level. Biogeochemical processes that occur at the interface between plant roots and the soil are widely recognized for their important role in the functioning of wetland ecosystems. In this context, ROOTARMOUR aims at providing novel insights into the involvement of root iron plaques (IP) – oxide coatings precipitated on the root surface under anoxic soil conditions – as hotspots of iron (Fe), phosphorus (P) and carbon (C) cycling in redox-dynamic environments. 

By building on a conceptual model of element redox cycling in the rhizosphere and focusing on rice as a model wetland plant, we aim at elucidating how multiple biotic and edaphic factors are implicated in root IP formation and related functions. 

The effects of changes in root traits induced by different P availability, in combination with the presence of soil or plant-derived dissolved organic matter, on the chemical, mineralogical and structural variability of these Fe oxyhydroxide coatings will be evaluated at an unprecedentedly high spatial and temporal resolution. This will be made possible by combining root trait evaluation, microsensor and imaging approaches, 13C-stable isotope tracing and X-ray microanalytical techniques in order to follow spatiotemporal changes in O2 and P gradients, and plant C allocation patterns in the rhizosphere, as well as the root morphology and distribution of Fe and P on the root surface. 

Empirical evidence for the underlying processes will also be provided by utilising artificial root systems that will allow to study the effects of specific variables on the interactions between Fe, P and C cycling at the root surface through a reductionist approach. Furthermore, these effects will be linked with specific IP-related functions, namely P availability and plant uptake, microbially-mediated Fe cycling in the rhizosphere, as well as organic matter turnover and stabilization in the root detritusphere. 

The project is expected to shed light on understudied rhizospheric processes that could have important implications on the productivity, resilience and environmental sustainability of wetland ecosystems.