VIROLOGY M. Cordero et al. (2003) Phytoparasitica 31(5):478-489 Identification of Tomato Mottle Taino Begomovirus Strains in Cuban Potato Fields Marlene Cordero, a Pedro L. Ramos, *'2 Lester Hernfindez, 2 Ana I. Fernfindez, 2 Ana L. Echemendfa, a Rudy Peral, 2 Gloria Gonzfilez, a Daniel Garcfa, 1 Surey Vald6s, 3 Ana Est6vez 4 and Keren Hernfindez 1 The presence of a begomovirus in potato plants with yellow mottle symptoms was determined for the first time in Cuba. The incidence of typical begomovirus-like symptoms in potato plants in some regions of Havana province (Giiira de Melena, San Jos6 de las Lajas, Giiines and Boyeros) during the growing seasons from 1992 to 1998 was in general low. However, in some cultivars belonging to the National Program for Potato Genetic Improvement, the incidence reached 100%. Yield losses, determined in 1992 and 1994, ranged as high as 19% to 56.33% depending on the cultivar. Characterization of the causal agent was done by light microscopy, host range (graft and mechanical transmission), DNA hybridizations, polymerase chain reaction, and restriction fragment length polymorphism analysis. Nucleotide sequence of the amplified fragments revealed the presence of Tomato mottle Taino virus. The virus was transmitted via tubers and has been detected in mixed infections with Potato virus X and with Potato leaf roll virus. KEY WORDS: Whitefly-transmitted geminiviruses; incidence; symptoms; Tomato mottle Taino begomovirus; potato; Cuba. INTRODUCTION Whitefly-transmitted geminiviruses are present in tropical and subtropical regions around the world, where they cause yield losses in numerous important crops (2,16,17,19). These viruses infect plants belonging to Cucurbitaceae, Fabaceae, Malvaceae, Euphor- biaceae and Solanaceae genera, causing striking golden and yellow mosaics, plant stunting and dwarfing, chlorotic mottle and curling of the leaves (12,18,19,27). Geminiviridae is a plant virus family characterized by small geminate virus particles, with either one or two circular single-stranded DNA molecules as genome (13). Members of this family are grouped into four genera (Mastrevirus, Curtovirus, Topocuvirus and Begomovirus), which differ in genome organization, host range and vectors (10). In Cuba, begomovirus- associated epidemics have exploded since the middle of 1989, and their increase is associated with increases in whitefly populations in various crops. To date, three different begomoviruses have been detected in tomato plantations: Tomato yellow leaf Received Aug. 29, 2002; revised ms. received Feb. 17, 2003; received in final form May 22, 2003; http://www.phytoparasitica.org posting Oct. 20, 2003. The first two authors contributed equally to this work. 1Inst. de InvestigacionesHorticolas Liliana Dimiaova, Quivic~n, La Habana, Cuba. 2Dept. de Plantas, Centro de lngenierfa Gen6tica y Biotecnologfa, La Habana, Cuba. *Corresponding author: [e-mail: pedro.ramos @cigb.edu.cu]. 31nst. de lnvestigaciones en Sanidad Vegetal, La Habana, Cuba. 41nst. Nacional de Ciencias Agrfcolas, La Habana, Cuba. 478 M. Cordero et al.