Molecular characterization of L2 gene of an Indian isolate of Bluetongue virus type-23

Bluetongue is an economically important arthropod borne viral disease of sheep, goat, cattle and wild ruminants. This disease is endemic in many parts of the world including India. Twenty one, out of possible 24 serotypes of Bluetongue virus (BTV) have been reported in India. L2 gene is of prime importance among all the 10 genes of the BTV, since it codes for the major serotype specific protein VP2, harboring the neutralizing epitopes. The genetic nature of L2 gene of Indian BTV isolates is poorly studied. In this study, the sequence information of one of the most important region of L2 gene of an Indian BTV-23 isolate was deciphered for the first time. On comparison with other available global isolates, the L2 gene revealed conservation of sequences within a serotype and variation among serotypes. The Indian BTV-23 isolate also revealed certain unique residues. The Indian isolate was found to be phylogenetically closely related to Australian BTV-23 isolate. A number of highly immunogenic epitopes were also identified for the Indian BTV-23 in this study. The sequence information, presented in this study will open up new vistas in progress towards development of a suitable prophylaxis and also serve as a base line data for future molecular epidemiological surveys around the world, in general and in Indian subcontinent, in particular.