Phenolic Compounds in the Plant Development and Defense: An Overview

Abstract

Phenolic compounds are produced by the plants mainly for their growth, development, and protection. These aromatic benzene ring compounds are very much essential during the plant’s biotic and abiotic stress interactions. They constitute an essential part of plant’s secondary metabolites and play a vital role in various physiological and mechanical activities. These diverse plant phenolic compounds act both as attractants and repellents toward various organisms in the environment. They could act as attractants toward the beneficial organisms and as toxicants against the invading pests and pathogens. These metabolite compounds often enhance during a plethora of stress conditions and act as the first line of defense to provide plant disease resistance. They are also known to influence the other plant metabolic pathways, namely phytoalexin biosynthesis and reactive oxygen species generation. These phenolic compounds participate both in the above- and below-ground plant defense systems. They are produced as root exudates and influence the soil diversity and the neighboring plants. The present review provides an overview of the roles of plant phenolic compounds in the plant kingdom as signaling compounds, pigment compounds, antimicrobials, and defense compounds.