ROOTOPOWER aims to develop a multidisciplinary suite of new tools targeted to the root system to enhance agronomic stability and sustainability of dicotyledonous crops under multiple and combined abiotic stresses: salinity, water stress, soil compaction and low fertilizer (N, P, K) input. Central to our approach is the use of tomato as a model species since it can be very easily grafted (usual commercial practise). This surgical technique allows precise assessment of the effect of altering root traits on crop performance independently of any shoot traits, since the scion (shoot) is constant.
This project will analyze and exploit the natural genetic variability existing in a recombinant inbred line population (RIL) from a cross between Solanum lycopersicum and S. pimpinellifolium and other selected mutants and functional lines (used as rootstocks) for their performance under multiple abiotic stresses and for their biotic interaction with natural soil microorganisms (mycorrhiza and rhizobacteria).
As sessile organisms, plants have developed great metabolic plasticity in order to cope with adverse biotic and abiotic stresses by modifying their primary and secondary metabolism.
The adaptation to stress can be interpreted in terms of changes in the assimilate allocation between energy producing (source organs) and energy consuming(sink) tissues, affecting biomass partitioning between different organs, and thereby crop yield.
The relationships between source and sink organs determine not only the plant growth and crop yield but also the adaptive capacity to environmental stresses. As a consequence, any mechanism affecting these relations could potentially have an influence on both economic yield and stress tolerance. Since the roots are the first tissues to encounter salt or other osmotic stress, it seems reasonable that they influence shoot physiology by means of root-to-shoot chemical signals (nutrients, hormones) allowing a differential assimilate partitioning and changes in source-sink relationships and affecting other physiological functions (leaf growth and senescence).
Our fundamental and applied research focuses on:
- Further understanding of root-to-shoot signalling and source-sink relationships in relation to the adaptation to different stresses (e.g. salinity, drought, pathogens, …).
- Exploitation of natural genetic variability ad biotechnology to minimize negative impacts of abiotic stresses on crops.
The scientific objectives of the project are:
- To identify new QTLs, candidate genes and novel signalling processes involved in root specific responses of tomato to abiotic stresses including 3 major nutrient deficiencies, and some naturally occurring stress combinations.
- To generate new genetic, genomic and physiological information, regarding the capacity or root colonisation by beneficial rhizosphere microorganisms (AMF and PGPR).
- To link the generated genetic, physiological and agronomical knowledge through the modelling of genetic and environmental dependencies of root system architecture.
- To evaluate selected and combined genetic plant material and microorganisms in controlled multi-stress environments and real Northern and Southern European cropping conditions.
- To understand biological interactions between roots and rhizosphere microorganisms (AMF and PGPR), and to identify at least one root genetic marker for each microorganism and the associated root-signalling mechanisms.
- To understand the genetic controls of different types of root-to-shoot signalling (hydraulic, ionomic and hormonal) that positively affect shoot performance under the abiotic stress conditions.