Role of Strigolactones in Maize Root Adaptation to Nitrogen and Water Deficiency

To cope with climate-induced abiotic stress, plants rely on the developmental plasticity of their root systems. As strigolactones (SLs) have emerged as key regulators of root architecture and stress adaptation, elucidating their specific functions is essential. To investigate their role in maize roots under nitrogen (N) and water deficiency, we compared wild-type (WT) and SL-biosynthesis mutant (zmccd8) seedlings grown in vermiculite for four weeks. We observed that zmccd8 plants developed a smaller root system than the WT plants, with fewer adventitious roots, particularly under N deficiency. Root transcriptome analysis revealed that N starvation triggered extensive pathway regulation in WT plants. In contrast, the mutant lacked these root-specific responses, indicating impaired transcriptional plasticity. Notably, although water stress had the strongest overall impact, both genotypes responded similarly. These findings indicate that, under our conditions, maize SLs act in a stress-specific manner, mediating crucial root adjustments for acclimation to N deficiency while playing a more limited role under water stress.