First Report of Lily X Potexvirus in the United States. T. C. Yang, Plant Pathology Department, University of Florida, Gainesville 32611 . F. W. Zettler, Plant Pathology Department, University of Florida, Gainesville 32611; and J. E. Polston, Gulf Coast Research and Education Center, Bradenton, FL 34203. Plant Dis. 80:1430. Accepted for publication 7 October 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-1430A.
Lily X potexvirus (LVX), first found in Europe (2) and then Japan (1), was detected in commercial Asiatic, Oriental, and Easter lily (Lilium spp.) bulbs destined for the U.S. market. The bulbs were from domestic and imported sources, and most were produced in northern California and The Netherlands, respectively. The antiserum used to detect LVX was from the Netherlands Flower Bulb Inspection Service, Lisse. The antiserum was cross-absorbed with healthy lily extracts, diluted 1:1000, and used in indirect enzyme-linked immunosorbent assay (I-ELISA), direct tissue blotting, and immunogold labeling tests. Homologous I-ELISA A405 values ranged from 1.00 to 1.50, compared with 0.05 to 0.10 for noninoculated controls. Red-violet laminate and vacuolate cytoplasmic inclusions like those of other potexviruses were detected in Azure A-stained lily leaf tissues that indexed positive for LVX by I-ELISA. LVX virions ca. 550 nm long were decorated with 10 nm colloidal gold particles in indirect immunogold labeling tests, whereas virions of lily symptomless carlavirus and tulip break potyvirus (ca. 650 and 750 nm, respectively) were not decorated. Tetragonia expansa Thunb, ex J. A. Murray, Chenopodium amaranticolor Coste & Reyn., and C. quinoa Willd, seedlings mechanically inoculated with LVX-infected lily leaf extracts and maintained at 20 to 24°C developed chlorotic and/or necrotic local lesions after 3 to 4 weeks. Mechanically inoculated L. formosanum Wallace and L. longiflorum Thunb, seedlings became systemically infected with LVX, but did not express foliar symptoms. However, infected plants did not bolt as quickly as healthy controls. These host range results were confirmed by I-ELISA and direct tissue blotting. Virus was not detected, however, in Nicotiana benthamiana Domin, and Gomphrena glo-bosa L. LVX was detected in 2 of 9, 3 of 9, and 4 of 4 commercial lots of Oriental, Asiatic, and Easter lily bulbs, respectively. Of the 413 Oriental, 228 Asiatic, and 273 Easter lily bulbs indexed in this study, 12.8, 10.5, and 8.8%, respectively, were infected with LVX. The highest incidence of LVX was noted in one lot of the Oriental lily cv. Stargazer from The Netherlands (50 of 101 bulbs). LVX could be a significant lily pathogen based upon its capacity to retard bolting and thereby affect crop scheduling.References: ( 1) S. Kimura et al. Res. Bull. Plant Prot. Serv. Jpn. 26:79, 1990. (2) O. M. Stone. Acta Hortic. 110:59, 1980.