Root developmental responses to temperature, soil compaction and light: implications for climate-resilient crop breeding

Abstract Background Elevated soil temperatures, soil compaction and altered light conditions in connection with latitudinal changes are emerging environmental constraints in crop productivity. Because roots play a central role in water and nutrient acquisition, understanding the mechanisms underlying root developmental plasticity under these stresses is becoming essential for improving crop resilience. Scope This review summarizes recent advances in the genetic, molecular and physiological mechanisms regulating root responses to increasing soil temperature, compaction and light. Roots respond to increasing temperature through thermomorphogenesis, which promotes adaptive growth under moderate warming, and heat-stress responses, which prioritize cellular protection under supra-optimal temperatures. The effects of soil compaction on roots result in morphological, anatomical, and growth dynamics changes including circumnutation. Climate change is expected to shift the optimal cultivation latitude of many crops, exposing them to changes in light intensity, spectral quality, and photoperiod that may result in yield penalties. Accordingly, responses to light are reviewed, both through direct root photoperception and systemic shoot-to-root signaling. Root adaptive responses to heat stress, soil compaction and altered light environments converge on interconnected regulatory networks involving auxin, HY5, PIFs, ethylene, YUCCA genes and PIN/AUX1 transporters, which integrate environmental signals to coordinate root developmental plasticity. Conclusion Much of the current knowledge still derives from model species, while targeted studies in crops remain limited. Integrating high-throughput phenotyping, quantitative genetics, omics approaches, crop modelling and genome editing technologies will accelerate the identification and deployment of adaptive root traits to soil temperatures, soil compaction and altered light conditions for breeding climate-resilient crops.