Jasmonic and salicylic acids (JA and SA) are plant phytohormones that play key roles in resistance/tolerance to biotic and abiotic stresses and interact with the other families of phytohormones to modulate growth and development. Understanding these PGRs and their roles has given modern agriculture new tools to fight diseases and pests, reduce the build-up of resistance to fungicidal and insecticidal active ingredients and enhance crop tolerance to a wide range of abiotic stresses, such as wet, dry, cold and hot.

Brassinosteroids (BRs) are growth hormones from the steroid family that are found in all plant species. They have a high-growth promoting activity, particularly in pollen and anthers, and take their name from the pollen of canola (Brassica napus), where they were initially discovered. BRs are involved in the control of cell division, elongation and differentiation throughout the growing season and are crucial for plant growth and development. And, acting as growth regulators, they are essential to many responses to stress.