Submitted to: Virus Diseases of the Poaceae
Publication Type: Book / Chapter
Publication Acceptance Date: November 7, 2002
Publication Date: October 20, 2004
Citation: Jensen, S.G., Grisham, M.P. 2004. Sorghum Mosaic. In: Lapierre, H., Signoret, P., editors. Viruses and Virus Diseases of the Poaceae (Gramineae). Paris: INRA. p. 547-548. Interpretive Summary: The Poaceae or grass family includes many of the most important plants to humans. They include wheat, rice, corn, sorghum, sugarcane, oats, barley, rye, millet, bamboo and numerous pasture and range grasses. The agricultural production of these plants and products derived from them can be limited by a number of diseases caused by viruses. This manuscript is a description of sorghum mosaic virus (SrMV) and the disease, mosaic, that it causes on sugarcane and is included in the book, Viruses Diseases of Poaceae. The book which contains detailed information about all the viruses known to attack this group of plants is designed to provide plant scientists with a concise, up-to-date summary of the information known about a particular virus and the disease it causes. For example, a scientist encounters mosaic disease on sorghum. From the descriptions in the book, the scientist determines that the symptoms of mosaic may be caused by maize dwarf mosaic virus or SrMV and how to determine which virus is the cause in this situation. A scientist can also find a summary of results from research done on a closely related virus and use that information to guide his or her research.
Technical Abstract: A detailed, technical description of sorghum mosaic virus (SrMV) and a summary of its role as a pathogen of sugarcane is presented for inclusion in the book entitled Virus Diseases of Poaceae (Gramineae). Sorghum mosaic virus is a definitive member of the genus Potyvirus in the family Potyviridae. The virus occurs primarily in the sugarcane growing areas of Louisiana and Texas and infects sugarcane, maize, and sorghum. The virion is not enveloped and is filamentous, usually flexuous with a modal length of 730-750 nm and a diameter of 13 nm. The SrMV RNA is monopartite, positive-sense, single-stranded of about 9.5 kb in length. The nucleotide sequences of 3'-terminal region of the genome (approximately 2kb in length) and the amino acid sequence of the protein coat have been used to show that SrMV is one of four closely related potyviruses. The related viruses are sorghum mosaic virus (SrMV), SCMV, maize dwarf mosaic virus (MDMV), and johnsongrass mosaic virus (JGMV). Three strains of SrMV have been identified. They are SrMV-SC-H, SrRMV-SC-I, and SrMV-SC-M. The virus is transmitted in a non-persistent manner by several species of aphids. The virus is vegetatively spread from field to field by infected sugarcane stalk cuttings. Field diagnosis of infected plants is primarily by visual observation of symptoms. Immunoassay and nucleic acid-based diagnostic protocols are available. The general symptom of mosaic disease on sugarcane and other hosts is a pattern of contrasting shades of green resulting from varying levels of chlorophyll concentration in the leaf blade. Sorghum mosaic virus has been reported to cause yield losses as high as 50% in susceptible cultivars, and as high as 20% in tolerant cultivars. Host resistance is the most effective method of controlling sugarcane mosaic.