NEWRoots

The molecular basis underlying root system architecture (RSA) in crops is important for improving soil capture of water and nutrients, thereby increasing drought resilience and productivity. The NEWRoots project aims to: - decipher at molecular and physiological level the regulative loop between RSA and nitrogen signalling, elucidating genetic and functional landscapes underpinning root plasticity; - evaluate in field trials, under different water and N supply, the impact of contrasting root growth angle (RGA) ideotypes on water and N-use efficiency and their effects on grain yield and quality. The proposed systemic approach will allow us to identify the functional units controlling the regulative loops between water and N sensing, RSA regulation and N uptake for wheat breeding programs.

Results achieved

The NEWRoots project investigated the genetic and molecular mechanisms that regulate root architecture in durum wheat and its response to nitrogen availability, with the goal of developing varieties that are more efficient in their use of water and nutrients and more resilient to climate change.

The research activities led to the identification of genomic regions and candidate genes involved in root development, pinpointing the QRga.ubo-6A locus as one of the main regulators of root growth angle. The integration of transcriptomic analyses, gene co-expression networks, and functional analyses highlighted the role of genes involved in hormonal signaling, particularly auxin signaling, opening new avenues for the genetic improvement of wheat through molecular markers and genome editing.

The project also significantly expanded the characterization of available genetic diversity by analyzing 218 durum wheat genotypes under controlled conditions with varying nitrogen levels. The use of an innovative, high-resolution aeroponic phenotyping platform allowed for dynamic monitoring of root system development and the identification of traits such as seedling root elongation rate, which are particularly promising for the selection of varieties with greater nitrogen use efficiency and beyond.

Field trials conducted on genotypes with different root architectures confirmed high genetic variability in response to conditions of limited water and nutrient availability. The integration of agronomic surveys, soil moisture sensors, and remote sensing technologies using drones made it possible to assess the impact of root architecture on productivity, resource use efficiency, and grain quality.

Overall, NEWRoots has generated new knowledge and tools useful for durum wheat breeding programs, contributing to the development of more sustainable varieties capable of maintaining high yields while reducing fertilizer and water requirements and minimizing the environmental impact of cultivation.

The project was structured around three main lines of research:

The first activity focused on studying the genetic and molecular bases that control root system development in response to different nitrogen levels.

Results: Through the analysis of recombinant lines with different root architectures, candidate genes and regulatory networks involved in root growth were identified, providing new insights into the mechanisms that determine root system plasticity.

The second activity analyzed the natural variability present in durum wheat germplasm. Using innovative high-resolution phenotyping platforms, hundreds of genotypes were studied under conditions of varying nitrogen availability.

Results: identification of root traits and sources of genetic variability useful for selecting varieties that are more efficient in resource use.

The third activity evaluated in the field the effect of different root architectures on water and nitrogen use efficiency, yield, and grain quality under varying water and nutrient availability conditions.

Results: The experimental trials identified promising genotypes and confirmed the role of the root system in wheat’s adaptation to environmental stresses.

Conclusions

The knowledge gained from the NEWRoots project provides an important foundation for the genetic improvement of durum wheat and will contribute to the development of new varieties capable of maintaining high yields with reduced water and fertilizer use, promoting agriculture that is more sustainable and resilient to climate change.