Characterization of a Novel Cucumber mosaic virus Isolated from Petunia hybrida

Department of Horticulture and Landscape, Seoul Women’s University, Seoul 139-774, Korea(Received on April 9, 2012; Revised on May 16, 2012; Accepted on May 16, 2012)Petunia hybrida is commonly used in landscapes andinteriors for its attractive flower. Virus-like foliar symp-toms, including a mosaic with dark green islands sur-rounding the veins and chlorosis on the leaf margins,were observed on a petunia plant from Icheon, Gyeonggi-do, Korea. Cucumber mosaic virus (CMV) was identifiedin the symptomatic petunia by serological testing for thepresence of CMV coat protein (CP) with a direct anti-body-sandwich-enzyme-linked immunosorbent assay.An agent was mechanically transmitted to indicatorplant species including Chenopodium quinoa. Exami-nation of the inoculated plant leaves by RT-PCR analy-sis and electron microscopy revealed the presence ofspecifically amplified CP products and spherical virionsof approximately 28 nm in diameter, respectively, pro-viding confirmation of a CMV infection. Analysis of CPsequences showed that CMV petunia isolate (CMV-YJC) shared 82.5−100% amino acid sequence identitywith CPs of representative CMV strains. Phylogeneticanalysis of CPs supports that CMV-YJC is a member ofCMV subgroup IA (CMV-IA) and has biological pro-perties of CMV-IA on host species. To our knowledge,this is the first report of CMV from P. hybrida in Korea.Keywords : coat protein, Cucumber mosaic virus, petunia,RT-PCR, sequence analysis, symptomPetunia hybrida is a perennial plant, known as the “king ofparterre flowers”. Petunia hybrida is one of six members ofthe Solanaceae grown primarily as an ornamental plant,and the most economically important due to its horticulturalvalue (Sink, 1984). Petunia is a popular bedding plant, thethird most valuable after geranium and impatiens (Hamrick,1997) and it is also grown in pots, hanging baskets, andbalcony/window boxes (Lesemann, 1996). Petunia plantsare propagated by seeds in nature, but new species ofvegetatively propagated petunia have been recently culti-vated as garden ornamentals in the world (Dai and Bao,2004). Plant viruses are responsible for severe diseases inmany crops, ornamental plants, and various plants, result-ing in major economic losses (Hull, 2002). Virus symptomsusually vary from local discoloration to severe perturbationof growth and development, or even death of the plant. Inmost relationships between virus and susceptible host, theinduction of disease symptoms results from colonization ofplant virus in which the agent modifies the metabolism ofits host at many different levels. In turn, host plant showsvarious responses to virus, depending upon genetic back-grounds, development stage and surrounding environment(Hull, 2002). Several viruses have been reported as naturallyinfecting petunia plants (Bellardi et al., 1996; Mavric et al.,1996; Pirone, 1978), and many viruses capable of infectingpetunia plants have been identified using artificial inocu-lation methods since petunia plants are frequently used asindicator hosts for virus diagnostic assays (Brunt et al.,1996; Lane, 1992). The virus most often detected in petuniaplants is Tobacco mosaic virus (TMV) and other commonlydetected viruses are and Chrysanthemum virus B (CVB),Cucumber mosaic virus (CMV), Tobacco ringspot virus(TRSV), Tobacco streak virus (TSV), Tomato ringspotvirus (ToRSV), and Tomato spotted wilt virus (TSWV)(Brunt et al., 1996; Lawson and Hus, 1994; Sanchez-Cuevas and Nameth, 2002). Among viruses infectingPetunia hybrida, CMV is a prevalent plant pathogen allover the world and has one of the widest host ranges of anyplant virus, infecting over 885 plant species in 65 families(Palukaitis et al., 1992). CMV is multi-component singlestranded virus, with three positive-sense RNA's (RNA1,RNA2 and RNA3) and an additional subgenomic RNA(RNA4) derived from RNA3 (Habili and Francki, 1974;Peden and Symons, 1973). RNA2 codes for the 2a protein,