The roles of strigolactones in plant resilience to environmental stresses

Strigolactones (SLs) are a group of phytohormones that enhance hyphal branching of arbuscular mycorrhizal fungi (AMF), promote seed germination of parasitic plants, and influence plant growth, development, and stress acclimation. SLs improve plant stress resilience by modulating shoot and root architecture, photosynthesis, nutrient homeostasis, and antioxidant defense. Under nutrient deficiency, SL accumulation enhances AMF colonization and triggers the expression of genes related to the nutrient starvation response. When subjected to drought, SLs mitigate water loss by modulating stomatal density and closure, cell membrane integrity, and anthocyanin biosynthesis. SLs also mitigate salinity and heavy metal stresses by maintaining ion homeostasis, while conferring thermotolerance and enhancing chilling tolerance. In this review, we highlight recent advances in SLs and their mechanisms in plant responses to environmental stresses, including nutrient deficiencies, drought, salinity, extreme temperatures, metal toxicity, herbivore attack, and pathogen infection. We further discuss how SLs interact with other phytohormones to coordinate the physiological, biochemical, and molecular regulatory events critical for plant acclimation to abiotic and biotic stresses.