Regulatory role of strigolactones in biotic stress tolerance

Plants are sessile organisms constantly exposed to several biotic and abiotic environmental stresses that severely affect plants' growth, development, and yield. Pathogens like bacteria, fungi, nematodes, pests, and viruses are the major causative agents of biotic stress, that adversely affect crop production. Plants have developed various adaptive mechanisms to overcome stress. These mechanisms are regulated by plant hormones that generate appropriate stress responses that help plants to thrive in stressful environments. Strigolactones (SLs) are plant hormones that can regulate growth and stress responses in plants. SLs have been discovered to be involved in resisting attacks from pathogenic bacteria, fungi, nematodes, aphids, and pests, thus conferring biotic stress tolerance in plants. It enhances plant biotic stress tolerance by inhibiting the growth of invading microorganisms, promoting stomatal closure, increasing H2O2 production, and cross-talk with other defense hormones. This chapter primarily focuses on how SL mediates biotic stress responses in plants.