Purification and Some Properties of a Virus Associated with Cardamom Mosaic, a New Member of the Potyvirus Group

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Abstract
The properties of cardamom mosaic virus (CarMV), which causes a severe disease of cardamom (Elletaria cardamom) in Guatemala, were investigated. CarMV was purified at Geneva, NY, using leaves collected from a cardamom plantation in Guatemala. Purified preparations contained numerous flexuous rod-shaped particles similar to those observed from leaf-dip extracts of infected leaves. Particles from purified preparations had a normal length of 700-720 nm. Cells of infected plants also contained pinwheel-shaped inclusion bodes that are typically induced by potyvirus infections. Three protein species with molecular weights of about 37,500, 32,200, and 29,000 were detected after purified preparations of CarMV were denatured with sodium dodecyl sulfate (SDS) and analyzed by electrophoresis in polyacrylamide gels. Presumably, the largest protein is the native capsid protein of CarMV and the smaller ones are proteolytic products of it. Antiserum prepared to CarMV reacted specifically with CarMV in SDS-agar immunodiffusion and in both indirect and direct enzyme-linked immunosorbent assay (ELISA). None of 16 potyvirus isolates tested reacted positively to CarMV antiserum in direct ELISA, but four viruses (zucchini yellow mosaic, papaya ringspot types w and p, cowpea aphidborne mosaic virus, and a severe strain [NL-8] of bean common mosaic) consistently gave positive reactions in indirect ELISA. We conclude that CarMV is a new potyvirus. The rapid and specific detection of infected plants by ELISA will help to implement control measures of the disease in Guatemala and elsewhere.