Defensive weapons and defense signals in plants: some metabolites serve both roles.
The defense of plants against herbivores and pathogens involves the participation of an enormous range of different metabolites, some of which act directly as defensive weapons against enemies (toxins or deterrents) and some of which act as components of the complex internal signaling network that insures that defense is timed to enemy attack. Recent work reveals a surprising trend: The same compounds may act as both weapons and signals of defense. For example, two groups of well-studied defensive weapons, glucosinolates and benzoxazinoids, trigger the accumulation of the protective polysaccharide callose as a barrier against aphids and pathogens. In the other direction, several hormones acting in defense signaling (and their precursors and products) exhibit activity as weapons against pathogens. Knowing which compounds are defensive weapons, which are defensive signals and which are both is vital for understanding the functioning of plant defense systems.
Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, Switzerland; Laboratory of Phytochemistry and Bioactive Natural Products, University of Geneva, Geneva, Switzerland.
Daniel
D
Maag
Matthias
M
Erb
Tobias G
TG
Köllner
Jonathan
J
Gershenzon
D000818:Animals; D048588:Benzoxazines / Q000378:metabolism; D005936:Glucans / Q000378:metabolism; D005961:Glucosinolates / Q000378:metabolism; D060434:Herbivory / Q000502:physiology*; D010937:Plant Growth Regulators / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
D048588:Benzoxazines; D005936:Glucans; D005961:Glucosinolates; D010937:Plant Growth Regulators; C048306:callose
benzoxazinoids; defenses against herbivores; defenses against pathogens; glucosinolates; phytohormones; secondary metabolites; volatiles