Exploring a multi-targeted CRISPR approach to identify missing molecular players triggering root foraging for nitrogen

• Applicant: Dr. Ricardo F.H. Giehl
• Subject Area: Plant Physiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 561197454

Nitrogen (N) is a crucial mineral element required by plants, playing a vital role in plant growth, development, and overall physiology. Plants have developed complex mechanisms to cope with fluctuating N levels in the soil, including the induction of root morphological and architectural changes. These responses reflect a foraging behaviour that increases the surface of contact of roots with the soil. Despite progress in understanding the mechanism underlying low N-triggered root developmental responses, critical questions remain unanswered, including the mechanisms linking N availability to downstream processes that prioritize root over shoot growth under low N conditions. Addressing these gaps in knowledge is essential for advancing our understanding of how N availability alters root development, with implications for mitigating losses of N from agricultural soils and improving crop resilience and productivity in low-input systems. By joining efforts and complementary approaches, this joint Israeli-German research project will combine the power of the innovative Multi-Knock system developed by the Shani lab at Tel Aviv University (Israel) with root phenotyping approaches and plant nutrition expertise of the Giehl lab at the Leibniz Institute of Plant Genetics & Crop Plant Research (Germany), with the aim to identify the missing genetic components underlying root foraging responses under low N. More specifically, this cooperative project will: a) generate unique, large-scale CRISPR libraries targeting multiple gene family members that are up-regulated in response to mild N deficiency in roots; b) perform multi-level phenotyping to identify redundantly hidden molecular components acting at different temporal, hierarchical and spatial scales; c) characterize the function of missing genetic components that define low N-induced root foraging responses; and d) explore the obtained data to investigate the association of root developmental traits with efficient N capture. The project will not only reveal the mechanisms required for triggering root N foraging but will also generate significant resources, including multi-targeting CRISPR libraries that allow overcoming functional redundancy across scales, resulting in a comprehensive set of mutants for up to 449 low N-induced genes. Besides identifying novel genes underlying plant adaptation to limiting N, this collaboration will explore the power of gene editing at the transcriptome scale and showcase the approach as an alternative to speed up trait-specific functional characterization in plants.

• DFG Programme: Research Grants
• International Connection: Israel
• Partner Organisation: The Israel Science Foundation
• Cooperation Partner: Dr. Eilon Shani