Physiological roles of karrikins in plants under abiotic stress conditions

Unlike people or animals, plants cannot escape or hide from adverse environmental conditions causing them stress. Instead, they are arrayed by various mechanisms, which enable them to cope with stress in situ. One of the most dangerous environmental factors, fire, produces compounds triggering various physiological responses. The compounds are found in smoke and are known as karrikins. The primary role of karrikins is germination induction of fire-following species, which are otherwise dormant for years until favorable conditions occur. In addition to seed germination, karrikins and their signaling pathway are involved in hypocotyl length and root development control, primary and secondary metabolism regulation, and plant-microorganisms interactions mediation. Unexpectedly, the product of destructive natural force mitigates the impact of several abiotic stressors, such as drought, salinity, low and high temperature, heavy metals, or nutrition deficiency. Therefore, karrikins may be a part of the solution for more resilient agriculture of future.