Plant Secondary Metabolism

Abstract

Abstract Plants synthesise an extraordinary array of natural products that usually do not play a role in their growth and development, and thus are traditionally referred to as secondary metabolites. However, recent advances in plant sciences have revealed that these compounds not only function in response to environmental stimuli, but also play more basic roles in plant growth. Secondary metabolites have several important roles in plants: they protect against herbivores and microbial infection and act as signals for symbiotic bacteria and mycorrhiza, attractants for pollinators and seed‐dispersing animals, allelopathic agents in natural habitats, physical and chemical barriers to abiotic stressors such as UV and evaporation and endogenous regulators of plant growth hormones. Many secondary metabolites are also useful for mankind as dyes, essential oils, flavouring agents, pesticides, pharmaceuticals, tanning agents and so on. Rapid advances in the metabolic engineering and synthetic biology of secondary metabolites have revealed novel physiological roles of these secondary metabolites in plants. Key Concepts: Plants synthesise a vast array of natural products (secondary metabolites) in response to environmental stimuli. Secondary metabolites have several important roles: they protect against herbivores and microbial infection and act as attractants for pollinators and seed‐dispersing animals, allelopathic agents in natural environments and endogeneous regulators of plant growth. Secondary metabolites are synthesised from primary metabolites such as acetate, pyruvate, and amino acids, and are mainly classified into three major groups; the terpenoids, the phenolics (mainly phenylpropanoids) and alkaloids.