Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2004
Publication Date: June 20, 2004
Citation: Grisham, M.P., Pan, Y. 2004. A Genetic Shift in the Predominant Virus Strain Causing Mosaic in Louisiana Sugarcane [abstract]. Phytopathology. 94(6):S36. Technical Abstract: Leaf samples were collected from 658 sugarcane plants showing mosaic symptoms in 2002 and 2003 at 11 locations within the Louisiana sugarcane industry. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine if the diseased plants were infected with sugarcane mosaic virus (SCMV) or sorghum mosaic virus (SrMV), the two viruses reported to cause mosaic in Louisiana. Virus strains were identified by restriction fragment length polymorphism (RFLP) analysis of the RT-PCR product. In most leaf samples, only one virus strain was identified; however, in approximately 5% of the samples, two strains were present and in one sample three strains. Among the strains identified, 67%, 10% and 3% were SrMV strains I, H and M, respectively. In surveys conducted between 1978 and 1995, over 95% of the virus isolates associated with sugarcane mosaic were SrMV strain H. Most of the remaining isolates were SrMV strain I, except for an occasional isolate of SrMV strain M. SCMV was not found in either survey. Approximately 13% of the SrMV isolates identified in 2002-2003 produced an RFLP banding pattern that did not match that of any described strain. Neither SCMV- nor SrMV-specific RT-PCR products were produced by 7% of the plants showing mosaic symptoms, suggesting that another virus may cause mosaic in sugarcane in Louisiana.