Involvement of Phenylpropanoid Pathway and Shikimic Acid Pathway in Environmental Stress Response
Anamika Paul, Krishnendu Acharya, Nilanjan Chakraborty
Abstract
The shikimic acid and phenylpropanoid pathways are two interlinked pathways for a large number of secondary metabolites biosynthesis of plants. The shikimic acid pathway involves the condensation of erythrose-4-phosphate (E4P) and phosphoenolpyruvate (PEP), and it ends with the formation of three aromatic amino acids. Among them, L-phenylalanine serves as a precursor of the phenylpropanoid pathway. Through phenylpropanoid pathway, several phenolic compounds like phenolic acids, flavonoids, monolignols, lignins, coumarins, anthocyanins, and condensed tannins are derived either directly or from many branches of this pathway (like flavonoid biosynthesis pathway and monolignol pathway). The production of such secondary metabolite is not only included for a broad range of applications in humankind, but also these are some eminent plants derived unique compounds that have a role in 28building defense responses in plants under the stresses. Hence, for resisting the environmental stresses like drought, temperature, UV-radiation, heavy metals, etc., plants exhibit responses via modification in the biosynthesis pathways by altering the gene expression or regulating enzymes activities, and alteration of their secondary metabolites production. Nowadays, abiotic stresses are in the pinpoint of focus by scientific communities and in this present chapter an updated information regarding potential roles of these two important pathways against challenging environmental circumstances has been focused.