Induction of plant defense response and its impact on productivity

Abstract

Plants encounter a wide variety of biotic agents, including bacterial pathogens that infect plant tissues and compromise plant survival. To protect themselves, plants have evolved mechanisms that specifically recognize pathogens and induce appropriate defense responses, such as the synthesis of cell wall reinforcement molecules, pathogen-degrading enzymes, and antimicrobial compounds. While expression of induced defenses is highly effective against most pathogens, it represents an energy-demanding process that can divert resources away from growth and yield. As a result, the constitutive expression of defense responses does not represent an efficient strategy to protect plants from disease, as it generally alters plant productivity and fitness. However, it is possible to potentiate plant defense responses by a first infection or selected treatment in a process known as priming. Primed plants can respond faster and more strongly to a secondary infection and will express enhanced resistance to various pathogens. As priming does not involve the constitutive expression of defense responses, this could represent a cost-effective mechanism for the induction of basal resistance against several plant pathogens.