ABSTRACT
Strigolactones are plant hormones derived from the carotenoid pathway. They were first identified as key chemical signals, responsible for the germination and host localization of the root-parasitic flowering plants of genera Striga and Orobanche. Since then, many of their functions were elucidated, including promotion of growth, hyphal branching of symbiotic arbuscular mycorrhiza and root development. Strigolactones are also important stress-response regulators, conferring abiotic stress tolerance to drought, salinity, heat, nutrient deficiency etc. Their positive role is achieved through improved root architecture, crosstalk with classical stress-responsive hormones, most notably abscisic acid, and enhanced mycorrhizal symbiosis, leading to improved stress tolerance. The exogenous application of synthetic strigolactone analogues such as GR24 and the engineering of the biosynthetic pathway confirmed their role in stress response. Meanwhile, the enhanced production of strigolactones may lead to increased susceptibility of crop plants to parasitic plants infection and, probably, to other pathogens. This dual role of strigolactones established an emerging field in the manipulation of crop-plant stress tolerance.
