A vital metabolic pathway in plants that synthesizes a wide range of aromatic compounds derived from the amino acid phenylalanine. This pathway produces phenylpropanoids, a diverse class of secondary metabolites that play critical roles in plant growth, development, and defense. Key products of the phenylpropanoid pathway include lignin (a structural polymer in plant cell walls), flavonoids, stilbenes, coumarins, and phenolic acids, all of which contribute to the plant’s ability to withstand biotic and abiotic stresses.
The pathway begins with the deamination of phenylalanine by phenylalanine ammonia-lyase (PAL), forming cinnamic acid, which undergoes a series of enzymatic modifications to generate various phenylpropanoid derivatives. These compounds are crucial for UV protection, pigmentation, pathogen defense, and signaling in plant-microbe interactions. Additionally, phenylpropanoids have significant ecological and economic importance, being sources of natural flavors, fragrances, dyes, and pharmacologically active substances used in traditional and modern medicine.
Other compounds produced through this pathway include lignin, flavonoids, coumarins, phenolic acids, stilbenes, and phytoalexins.
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