Polyphenol Oxidase (PPO) in Early Stage of Browning of Phalaenopsis Leaf Explants

Abstract

Explant browning is one of the most common problems during the early stage of tissue culture. The aim of this study was to explore the roles of polyphenol oxidase (PPO, EC 1.10.3.2) in the browning process of leaf explants of Phalaenopsis (Doritaenopsis Queen Bee " Red Sky ") under a routine culture condition. Along with the observation of the time course of browning and PPO distribution, PPO gene expression in leaf explants were investigated. In addition, the expression and activity of PPO were also examined. This work provides some insights into further understanding the relationship between PPO activation and explant browning.