Physiological Responses to Infection by Tomato bushy stunt virus in Different Host Plants

An Egyptian isolate of Tomato bushy stunt virus, the TBSV Egh was inoculated on two different economically important hosts Lycopersicon esculentum and Cucurbita pepo. Both Elisa and RT-PCR were compared with respect to sensitivity of detection of virus infection at different days post inoculation (dpi), where the molecular technique was found to be more sensitive. At 15 dpi, systematic symptoms and some physiological responses were compared in the two hosts. Systematic symptoms varying from chlorosis, stunting to malformation on L. esculentum to chlorosis, necrotic patterns and stunting on C. pepo. TBSV Egh-infection resulted in a decline in growth of both hosts compared to control plants. At the same time, a significant increase in lipid peroxidation level of TBSV Egh-infected plants was found compared to uninfected plants. Assessment of the activities of the key enzymes for nitrogen assimilation, glutamine synthetase (GS) and glutamate synthase (GOGOAT) of TBSV Egh-infected plants revealed variable significant responses. Free amino acids composition of TBSV Egh-infected plants showed distinct disturbance compared to that of uninfected plants.