Study of biochemical and histopathological changes induced in the sweet pepper (Capsicum annuum L.) in response to Chilli leaf curl virus infection

A survey was conducted at the horticulture field at Lucknow, India and about 64% leaf curl disease incidence was observed on sweet pepper (Capsicum annuum L.) plants. The severe leaf curl disease was observed in several sweet pepper plants causing deterioration of size and quality of fruit. Therefore, this study was undertaken to characterize the pathogen to cause leaf curl disease in sweet pepper and explore the impact of virus disease on fruit quality of sweet pepper plants. The sequence analysis of full-length genome of detected virus and associated betasatellite isolated from the infected plants revealed the occurrence of Chilli leaf curl virus (ChiLCV) in the association of tomato leaf curl Bangladesh betasatellite (ToLCBDB). The sweet pepper seedlings were co-inoculated with agroinfectious DNA clones of ChiLCV and ToLCBDB which developed similar leaf curl symptom as was observed naturally. The higher accumulation of proline, malondialdehyde, sugar, and polyphenols were observed in virus infected plants as compared to the control. The activities of defense-related enzymes (APx, GPx and SOD) were elevated to cope with the virus-induced stress in infected plants. The fruits in infected plants was deformed compared to control and the nutritional quality of fruits in infected plants was compromised as carotenoids and vitamin-C contents reduced significantly. Moreover, the histopathological evaluations of these symptomatic plants suggested that virus infection severely affects the vascular tissue of leaf and stem. The phenomenon of alterations in the stress related biochemicals of sweet pepper plants due to ChiLCV infection is demonstrated which measures the fruit quality deteriorated by this interaction.