Function(s)/Role(s) of Polyphenol Oxidases

Abstract

Plants under native conditions are exposed to different abiotic and biotic stresses that impact the plant fitness either individually or together. Under majority of situations, the plants possess a diverse range of defense traits that help in reducing or eliminating the effects of these stresses. The secondary metabolites that include defense-related proteins play a major role in plant defense. Generally, spatial and temporal differences are observed with occurrence of biotic and abiotic stresses. Additionally, multiple stresses might impact the plant growth simultaneously; therefore, plant defense mechanisms must exhibit plasticity to combat these different stresses. The flexibility of secondary metabolites is due to (i) their role in defense against several stresses both biotic and abiotic and (ii) they are inducible, i.e., secondary metabolites are only expressed or expressed under stress (Thipyapong et al. 2007).