Role and regulation of plants phenolics in abiotic stress tolerance: An overview

Plant phenolics or polyphenols, the aromatic compounds with one or more hydroxyl groups, are produced by plants mainly for protection against stresses. Phenolics are secondary natural metabolites emerging from the shikimate/phenylpropanoid pathway or polyketide acetate/malonate pathway, producing monomeric and polymeric phenols and polyphenols, which participate in a wide range of physiological activities in plants. Plants are known to have synthesized thousands of different phenolic compounds throughout the course of evolution to cope with constantly changing environments. Plants accumulate phenolic compounds in their tissues as an adaptive response to adverse environmental conditions and have a key role in the regulation of various environmental stresses, such as high light, low temperatures, pathogen infection, herbivores, and nutrient deficiency. This chapter details the biosynthesis, role, and regulation of plant phenolics in response to various abiotic stresses.