February 13, 2003
From: American Phytopathological Society, Plant Disease Notes [edited]

Pepper golden mosaic virus affecting tomato crops in the Baja California Peninsula, Mexico

RJ Holguin-Pena, R Vazquez Juarez, Centro de Investigaciones Biologicas del Noroeste, PO Box 128, La Paz, Baja California Sur 23000, Mexico; RF Rivera-Bustamante, Departamento de Ingenieria Genetica, Centro de Investigacion y de Estudios Avanzados, U Irapuato, PO Box 629, Irapuato, Gto 36500, Mexico. Plant Dis 2004; 88: 221; published on-line as D-2003-1127-01N, 2004. Accepted for publication 27 Oct 2003.

In the state of Baja California Sur, tomatoes (_Lycopersicon esculentum_ Mill.) are cultivated on about 1000 ha. Occurrence of viral diseases is currently causing low yields and severe losses. Virus-like symptoms (severe leaf curling, stunting, reduced leaf size, and mosaic patterns) were observed on 99 per cent of tomato plants in 2002 in La Paz, Baja California Sur. Whiteflies (_Bemisia tabaci_ Gennadius) were present in affected fields and appeared to be associated with the disease.

The virus was experimentally transmitted from infected plants to tomato and peppers seedlings by whiteflies and as infectious DNA (replicative form) by mechanical and biolistic inoculation. Symptoms similar to those found in
the field were observed in experimental transmission assays. DNA from inoculated plants was extracted and analyzed by DNA hybridization and polymerase chain reaction (PCR) using degenerate (1) and specific (2) primers. The PCR products (1.1 kb) obtained from the common region (GenBank Accession No. AY368336) suggested the presence of a bipartite geminivirus.

The nucleotide sequence of the PCR products showed a 98 per cent identity to Pepper golden mosaic virus-Tamaulipas strain (PepGMV-Tam) in the intergenic region (IR). Similar identities (97 per cent) were obtained by
using the predicted amino acid sequences of the amino termini of the coat proteins. Identities in the replication proteins (92 per cent) and IR iterative sequence analyses show that the PepGMV-La Paz isolate is a closely related strain of PepGMV-Tam.

To our knowledge, this is the first report of PepGMV affecting tomato crops in Baja California Sur, Mexico.

References:
(1) MR Rojas, et al. Plant Dis 1993; 77: 340.
(2) I Torres-Pacheco, et al. Phytopathology 1996; 86: 1186.

[Pepper golden mosaic begomovirus, formerly designated as Serrano golden mosaic virus (SGMV) and Texas pepper virus (TPV), is present in Costa Rica, Guatemala, Honduras, Mexico (7 states), and USA (Texas), and causes significant crop losses. Scientists in Mexico are attempting to select tomato plants that appear to be asymptomatic following inoculation with PepGMV, suggesting that they may be useful in developing resistant cultivars. Part of the resistance mechanism appears to be the lack of virus movement in infected plants. At least 2 closely related strains of PepGMV (Tamaulipas and La Paz) are present in Mexico.
A useful reference: <http://gemini.biosci.arizona.edu/viruses/pepgmv/index.htm> - Mod.DH]