MOLECULAR GENETICS OF ENZYMATIC BROWNING IN POST-HARVEST FRUITS: GENE EXPRESSION, REGULATORY NETWORKS, AND FUNCTIONAL GENOMICS

Abstract

Enzymatic browning is a major post-harvest disorder that adversely affects the quality, shelf life, nutritional value, and marketability of fruits. The process is primarily driven by the oxidation of phenolic compounds catalyzed by oxidative enzymes, but recent studies indicate that browning is regulated by complex genetic, molecular, and physiological mechanisms. This review aims to synthesize current knowledge on the molecular genetics of enzymatic browning in post-harvest fruits, with particular emphasis on gene expression dynamics, regulatory networks, and functional genomics approaches involved in browning development and control. Relevant literature on post-harvest browning, transcriptomics, proteomics, metabolomics, epigenetics, gene regulation, and genome-editing technologies was critically analyzed to evaluate advances in understanding browning-associated molecular mechanisms across diverse fruit crops. Recent research has revealed that enzymatic browning is governed by intricate interactions among oxidative enzymes, phenolic metabolism, reactive oxygen species (ROS), hormonal signaling pathways, transcription factors, non-coding RNAs, and epigenetic modifications. Multi-omics technologies have enabled the identification of candidate genes, molecular markers, and regulatory pathways associated with browning susceptibility and post-harvest quality. Comparative studies across fruit species have demonstrated both conserved and species-specific molecular responses, while functional genomics tools, including RNA interference and CRISPR-based genome editing, have provided opportunities for validating key genes and improving browning resistance. Advances in molecular genetics and functional genomics have substantially improved understanding of enzymatic browning mechanisms. Integrating multi-omics, systems biology, and precision breeding approaches offers promising strategies for developing browning-resistant fruit cultivars, enhancing post-harvest quality, and reducing global post-harvest losses.