From roots to resilience: Strigolactones for boosting crop resilience and productivity under stressful environments

Environmental stresses like drought, salinity, and extreme temperatures disrupt physiological processes, threaten crop growth, and reduce yields, thereby jeopardizing global agricultural sustainability and food security. Therefore, improving crop resilience is crucial for boosting agricultural productivity amid unpredictable climates and a growing population. Strigolactones (SLs) are carotenoid-derived novel phytohormones exuded by roots and offer promising potential to augment crop resilience and productivity under challenging environments. SLs are involved in plant development through the regulation of plant signaling, shoot and root architecture, mycorrhizal establishment, and controlling parasitic weeds. This review explores SLs' biosynthesis, signaling pathways, underlying mechanisms involved in mitigating environmental stresses and nutrient deficiencies, and pathways for developing stress-resistant cultivars and sustainable agrochemicals for sustainable crop production. SLs, by enhancing hyphal branching in arbuscular mycorrhizal fungi (AMF), promote root growth, nutrient uptake, and water absorption. Transcriptomic analysis showed that SLs regulate stomatal conductance, enhance antioxidant activity, improve plant morphology, and stress resilience by modulating different hormonal pathways, such as auxin, abscisic acid (ABA), cytokinin (CK), and gibberellic acid (GA). Leveraging these functions, SLs can aid in developing crop cultivars with optimized vegetative and root systems tailored to withstand various adverse environmental conditions through targeted genetic breeding. Advances in microbial engineering enable efficient and scalable production of natural and novel SLs in hosts like yeast or Escherichia coli. Moreover, formulating SLs and their analogs, like GR24 and Nijmegen-1, enhances their stability, solubility, and effectiveness in field applications. Hence, clear insights about the potential capabilities of SLs could enable the development of stress-resilient plants with improved yields amid changing climates.