Department of Microbiology, Swami Shraddhanand College, University of Delhi, Delhi-110036, 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.
Plant viruses have been the pioneering microbes in which the breakthrough discoveries of RNA as the genetic material and their structural and genomic studies paved the way for some important developments in molecular biology. Various plant viral gene sequences like promoters (eg.35S promoter of Cauliflower Mosaic Virus); transcriptional termination signals, translational enhancer signals (eg. TMV W leader sequence) have been extensively used to express genes of interest and obtain the desired proteins in plant systems. Plant viruses have shown tremendous potential for use as genetic vectors because of their high levels of expression and at the same time regulation of mRNA through ribozymes, internal ribosome entry sites (IRES), differential expression of products from a single transcript by ribosomal frame shift and read through sequences.Further, the use of sub genomic promoters and modulation of translational steps through viral proteases have helped in achieving the desired levels of protein expression. The use of naturally occurring or mutated a virulent strains for cross protection has been successfully deployed to impart resistance against some viral diseases. Also through improved methods of genetic engineering, viral derived genes either alone or along with plant-derived genes have been utilized in obtaining transgenic resistance and successfully commercialized in some important plant viral disease problems, which pose a serious threat to crop cultivation particularly in developing countries. Plant viruses have shown tremendous potential for commercial production of different kinds of vaccines against several human and animal diseases and also for the production of therapeutic proteins and peptides of interest. Biologically active peptides have been presented on virus capsid proteins as carriers of antigenic epitopes or exposed on virus like particles. In the post genomic era, when a large database of sequence information is available for many plants, reverse genetics approach using viral sequences and also virus induced gene silencing (VIGS) technology holds a lot of promise in determining the gene function of plant genes. VIGS deploys viral vectors carrying a portion of a gene of interest to produce a double stranded RNA which triggers the silencing of the target gene, mimicking a loss of function mutant. Plant viruses have recently attracted attention as biological templates for assembly of nanostructures and nanoelectric circuits and their potential role in Nanotechnology shall be presented.
