*2.9.1 Introduction*

Strigolactones are a class of carotenoid-derived plant hormones that are found in a wide variety of plant species, ranging from mosses to higher plants. They are crucial for the stimulation and branching of parasitic plants as well as the symbiosis and growth of arbuscular mycorrhizal fungus in soil. In 1966, cotton root exudate was the source of the first Strigolactones to be identified, called Strigol. Its name was connected to the Striga plant genus, a typical parasite of this crop. The creation of adventitious and lateral roots, as well as the induction of secondary growth, acceleration of leaf senescence, promotion of internode growth, and root elongation are all regulated by Strigolactones [35].
