PPOX and viral infectious disease: Polyphenol oxidase (PPO) has been found to assist in basal defense against fungi, bacteria, and viruses (Poiatti et al., 2009) and PPO transcript levels were elevated in the resistant chilli cultivar Punjab Lal, suggesting PPO could play a role in initiation of basal defence against ChiLCV infection (Kushwaha et al., 2015), or the upregulation of this gene reflects a general stress response to virus infection.