1Division of Plant Quarantine, National Bureau of Plant Genetic Resources, New Delhi-110012.
2NBPGR Regional Station, Rajendra Nagar, Hyderabad-500030.
Abstracts of Research Papers Presented during the National Symposium of Indian Virological Society at Unit of Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi-110 012, October 14–1.
A number of plant viruses are of great quarantine significance as they can be introduced into a new area through seeds and other planting material. More than 100 viruses are transmitted through true seeds and many more infect vegetative propagules. A number of techniques ranging from biological to molecular are being used for detecting plant viruses. The detection of viruses assume special importance in quarantine where routine tests are to be carried out on plant parts/planting material within a short span of time in a given amount of sample. This implies that often the exotic or the unknown viruses or their virulent strains need to be detected reliably and quickly for which neither the antisera are locally produced nor the appropriate primer sequences are available unless the virus in question is already characterized and sequenced, and the information is in public domain. Besides, if sample size is very small as in case of germplasm, it is not practical to directly test the seeds as a part of the samples has also to be released to the indenter. It thus takes a crop season to release the harvest only from the indexed virus-free plants from post-entry quarantine nurseries. If the sample size is big, proper sampling procedures need to be followed and a group testing approach has to be adopted to ensure that the consignment of seed lot is free from the virus. Adopting a workable strategy, a number of exotic viruses have been intercepted in imported germplasm which includes the ones yet not reported from India and also not known to occur on particular host(s) such as Cowpea mottle virus and Tomato black ring virus (TBRV) in cowpea; Alfalfa mosaic virus, Cherry leaf roll virus, Soybean mosaic virus, Southern bean mosaic virus and TBRV in French bean; Peanut stripe virus and Peanut mottle virus in groundnut; Cowpea aphid-borne mosaic virus (CABMV) in mungbean; Broad bean stain virus in pea and CABMV in soybean. The importance of quarantine has increased manifold in the WTO regime and adopting not only the appropriate technique but also the right strategy for virus detection would go a long way in ensuring virus-free trade and exchange of germplasm.
