Role of Ethylene in Combating Biotic Stress

In plants, the hormone ethylene is an important signal in stressful conditions, whether biotic or abiotic. Its production can be induced by the invasion of pathogens in plants, and it may then activate plants' defense-related processes. Ethylene is found to accelerate the ripening of fruit as well as senescence in leaves. It is formed from methionine via S -adenosyl-methionine (AdoMet); the cyclic, non-protein amino acid 1-aminocyclopropane-1-carboxylic acid (ACC) and biotic stress also induce the production of ethylene. Many diseases and a loss of yield have been reported in plants due to biotic stress: approximately 20–40% of crop yields are lost due to pests and pathogens every year. Ethylene is known to enhance the resistance of crops to various diseases by reducing the accumulation of reactive oxygen species under biotic stress. This chapter deals with biotic stress in plants and the role of ethylene in combating those stressful conditions.