Tomato plants grown in commercial greenhouses in Sonora, Mexico, developed either yellow mosaic, leaf curling, and stunting (phenotype 1; 20 to 35%) or chlorosis and a feathery appearance of leaves (phenotype 2; 15 to 25%) in December 1997 and again in October 1998. Polymerase chain reaction (PCR) with diagnostic primers (prAV324 and prAC889) that amplify an approximately 576-bp fragment of the coat protein (CP) gene of whitefly-transmitted geminiviruses indicated the presence of a begomovirus. Biolistic inoculation of tomato seedlings with RNase-treated extracts of three symptomatic tomato samples, each, resulted in reproduction of disease symptoms. With PCR primers prAV2644 and prAC1154 (1), the entire CP (approximately 776 bp) and its flanking sequences were amplified from extracts of symptomatic tomato, and amplicons were cloned and sequenced. Comparisons of a minimum of three CP gene sequences from each phenotype revealed the presence of at least two begomoviruses. The phenotype 1-associated CP gene shared 92.6, 86.2, and 85.3% identity with the CP sequence of chino del tomate (CdTV) [AF106936], tomato mottle, and abutilon mosaic geminiviruses, respectively. The CP sequence associated with phenotype 2 was 94.6, 77.1, and 77.1% identical to pepper hausteco (PHV) [X70418], bean golden mosaic-Guatemala (BGMV-GU), and Texas pepper (TPV) gem-iniviruses, respectively. Previously, CdTV was reported from tomato in Chiapas, Morelos, Sinaloa, and Tamaulipas, Mexico, while PHV has been identified in Guanajuato, Quintana Roo, Sinaloa, and Tamaulipas, Mexico, and in Texas (2). This is the first report of CdTV-like (>92% identity) and PHV-like (>94% identity) geminiviruses associated with greenhouse-grown tomatoes in Sonora, Mexico.
References: (1) A. M. Idris and J. K. Brown. Phytopathology 88:648, 1998; (2) I. Torres-Pacheco et al. Phytopathology 86:1186, 1996.
