Biochemical and Molecular Regulation of Phenylpropanoids Pathway Under Abiotic Stresses

Phenylpropanoids have an important role in plant adaptation in different environmental conditions. Abiotic stresses usually increase the phenylpropanoids pathway with increase of phenolics, flavonoids, anthocyanins, and lignin. These compounds can protect plants against diseases or pests. The chemical structures of phenylpropanoids can reduce the reactive oxygen species by reducing the free radicals. Therefore, the activation of phenylpropanoid genes contemporary occurs with stress sensing in plants. Understanding the regulation of phenylpropanoids pathway can be exploited in agricultural crops and expand the cultivation even where stressful conditions represent a limiting factor. High-light conditions, low temperatures, drought, salinity, and senescence are stressful conditions that positively activate the phenylpropanoids genes. Recently, microRNAs have been demonstrated to regulate the phenylpropanoids and the synthetic miRNAs can be exploited for regulating the expression of phenylpropanoid genes. The enhancement of plant tolerance against the abiotic stresses can be obtained through the genetic improvement of plants with higher ability to accumulate phenylpropanoids.