Depatmaent of molecular biology & genetic engineering, College of basic sciences & humanities, G.B.P.U.A.&T, Pantnagar-263145, India.
Abstracts of the papers presented at the International Conference of Indian Virological Society on “Emerging and Re-emerging viral Diseases of the Tropics and Subtropics” at Indian Agricultural Research Institute, New Delhi, India, December 11–14, 2007.
Tomato (Lycopersicon esculentum) is extensively grown as a vegetable as well as fruit, constituting about 7.7% of total vegetable production in India. In tomato, viral diseases are responsible for yield loss at an alarming pace of 40–100% in epidemic years. Tomato leaf curl virus, Tomato black ring virus, Tomato ringspot virus, Tomato tospovirus, Tomato spotted wilt virus are some of the common viruses impairing tomato production. Study of plant virus interactions at molecular level will devise new strategies to combat these infections. Present study was carried out to elucidate the role of proteases and protease inhibitors in programmed cell death (PCD) triggered during viral pathogenesis. Tomato tospovirus which causes necrosis in plant has been postulated to induce PCD upon infection. Therefore a comparative study between Tomato leaf curl virus and Tomato tospovirus infected samples which were used as a reference, was made to study the extent of PCD in response to leaf curl infection through biochemical and molecular approaches. Histochemical staining revealed more prominent reddish brown lesions in Tospovirus infected samples as compared to leaf curl virus. Application of biochemical assays concluded a negative relationship between proteases and inhibitors in viral pathogenesis. By modulating the activity of inhibitors, PCD involved in necrosis can be checked and resistance against the virus can be imparted. Further study of Tomato leaf curl virus and Tomato tospovirus proteins using bioinformatics tools provided a clear indication that plant cystatin is having cleavage sites for serine and metalloendopeptidases and possibility is there the proteases encoded by viral genome may play a significant role in deciding the fate of plant viral interaction and development of symptoms.
