RESUMEN
A method for isolation and purification of plant viruses was described. The method involved use of organic solvents, differential centrifugation and density gradient centrifugation on step and linear caesium sulphate gradients with which a sucrose cushion was used. The method was found suitable for purification of a range of plant viruses belonging to different virus groups and representing the different shapes reported for plant viruses. The plant viruses purified through this method included Potato virus Y [PVY], Tobacco etch virus [TEV], Alfalfa mosaic virus [AMV], Cucumber mosaic virus [CMV], Tobacco mosaic virus [TMV] and Tomato yellow leaf curl virus [TYLCV]. Both the step and linear gradients of caesium sulphate gave similar results in isolation and purification of these viruses and no appreciable differences were observed between them when either of which was used