The Korean Soclety of Plant Pathology : K ; Virology and Virus Diseases : K-17 ; Partial sequence analysis of Saguaro cactus Carmovirus isolated from the grafted cactus in Korea

A Korean strain of Saguaro cactus virus (SgCV-kr), the genus of Carmo-virus, was isolated from the grafted cactus in Korea. The grafted cactus is one of the most important exporting plants in Korea and cactus-infecting viruses have caused poor cultivation in cacti-growing farm. SgCV-kr was detected from both rootstock and scion of multiple grafted cactus plants and occasionally showed mixed-infection with other viruses (ZVX, SVX, OVX, CVX and RCNaV) by RT-PCR assay. The virus is asymptomatic in the cactus plant but produces local lesion on the virus-inoculated leaves of Chenopodium amaranticolor and Gomphrena globosa. The 3,166 nucleo-tide was partially determined to analyze SgCV-kr genomic sequence. It encodes the 37 kDa of coat protein (CP), 6/9 kDa of two small ORFs cor-responding movement protein and 57 kDa containing GDD motif of RNA-dependent RNA polymerase. The comparison of amino acid (aa) sequence between SgCV-kr and other sixteen carmovirus species showed similarity of 21.2-66.2% in the CP, 17.5-75.0% in the P9, 20.7-81.0% in the P6 and 42.2-71.4% in the 57kDa. The CP of SgCV-kr showed 66.2 and 99.7 % iden-tities with two SgCV strains isolated in USA and Germany, respectively. Phylogenetic analysis indicated SgCV-kr is related with CaMV, CbMV and HCRSV excluding SgCV strains. This research is the first report about SgCV of cactus-infecting carmovirus in Korea.