Antioxidant and oxidant levels of pepper (Capsicum annuum cv. 'Charlee') infected with pepper mild mottle virus

Abstract

Total antioxidant status (TAS), total oxidant status (TOS), as well as total phenol (TP), free phenol (FP), conjugated phenol (CP), and the vitamin C content of pepper plants (Capsicum annuum cv. 'Charlee') infected with Pepper mild mottle virus (PMMoV) were determined via a novel automated antioxidant system using test kits. PMMoV was first identified in Turkey in 1994 in commercial pepper (Capsicum annuum cv. 'Charlee') fields and caused an outbreak in southern Turkey by 2006, especially in greenhouses. Infected plants were confirmed by ELISA using commercial kits for the virus. The infected plants had stunted growth; and leaves and fruits became mottled, puckered, malformed, deformed, and marked by off-colored sunken areas. Fruits expressing virus symptoms were utilized for biochemical analyses. The percent ratio of TOS to TAS was calculated as the oxidative stress index (OSI). The TAS level and the vitamin C content were found to be significantly lower in infected peppers as compared to healthy peppers. However, TOS, OSI, TP, FP, and CP levels were significantly higher in infected pepper fruits than in healthy ones. In this study, it has been demonstrated that low levels of TAS and high levels of TOS, as well as high OSI status, reflects the quality of peppers. Using this method, the quality of fruits and the condition of plants can be determined in advance of stress development.