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Purification and Properties of Citrus-Leaf-Rugose Virus. S. M. Garnsey, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Southern Region, U.S. Horticultural Research Laboratory, Orlando, Florida 32803; Phytopathology 65:50-57. Accepted for publication 23 July 1974. DOI: 10.1094/Phyto-65-50.

The name “citrus-leaf-rugose virus” (CLRV) is proposed for a mechanically transmitted citrus virus which was discovered in Florida and provisionally described earlier as “crinkly-leaf-type virus.” CLRV was transmitted to numerous citrus and herbaceous hosts. CLRV isolates differed in their stunting effects on grapefruit (Citrus paradisi ‘Duncan’) seedlings, and strain interference between isolates was shown. CLRV symptoms differed from those caused by citrus variegation virus (CVV) in citrus and herbaceous hosts. Cross-protection between CLRV and CVV was shown in citron (C. medica ‘Etrog’). CLRV was readily purified from young citrus-leaf tissue by use of calcium phosphate gel clarification and differential and density-gradient centrifugation. Three to 5 mg of purified virus were obtained from 100 g of citrus-leaf tissue. CLRV particles were isometric and averaged 28 nm in diameter. Purified virus had an absorption minimum at 244 nm, a maximum at 260 nm, and a 260/280 ratio of 1.4 to 1.45. The thermal inactivation point was near 60 C. Longevity in vitro was 1 to 2 days at room temperature in crude extracts. Purified CLRV was stable for several months at 4 C. Antisera were prepared to purified CLRV, which reacted to purified virus and to extracts from CLRV-infected citrus and herbaceous hosts. CLRV antiserum reacted heterologously to CVV, but not to tobacco streak or cowpea mosaic viruses.