Any of a group of plant hormones that play a vital part of the plant’s defensive response against attack by herbivorous insects, fungi, and other pathogens. Substances released by such an attack act as elicitors; they bind to plasma membrane receptors and trigger the hydrolysis of the unsaturated fatty acid linolenic acid to produce jasmonates, principally jasmonic acid and methyl jasmonate. These can travel in phloem to undamaged tissue, where they activate genes encoding defensive proteins, e.g. protease inhibitors that interfere with digestion in the insect’s gut. They are also believed to act as mobile long-distance wound signals (see systemic signalling). Jasmonates modulate the action of many other genes as well, influencing processes ranging from seed germination to nectar production, fruit ripening, root development, and the formation of mycorrhizal symbioses, in conjunction with other hormones.