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First Report of Tobacco mild green mosaic virus in Capsicum chinense in Venezuela

In July 2003, noticeable deformations of leaves were observed on a local variety of Capsicum chinense, also called ‘Aji dulce’, from a pepper plantation located in Venezuela, (Monagas State). ‘Aji dulce’ is a basic ingredient of the Venezuelan gastronomy with an estimated cultivated area of 2,000 ha. The seeds of this local pepper are obtained by the growers who reproduce and multiply their own seeds every year. Seeds of affected plants were sent to our laboratory, and a group of approximately 100 seeds was sown in a controlled greenhouse that belongs to the Polytechnic University of Valencia, Spain. Three months later, obvious curling and bubbling developed on the leaves of the plants. Extracts of symptomatic plants tested negative for Tomato mosaic virus (ToMV), Tobacco mosaic virus (TMV), Pepper mild mottle virus (PMMV), and Tobacco etch virus (TEV) by double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISA) with policlonal antibodies specific to each virus (Loewe Biochemica GMBH, Sauerlach, Germany; Phyto-Diagnostics, INRA, France). Total RNA was isolated from 0.5 g of original seed sent from Venezuela and from 25 samples of leaves of plants grown in the greenhouse with an RNeasy Plant Mini Kit (Qiagen Sciences, Germantown, Maryland). The RNA isolated was used in reverse transcription-polymerase chain reaction (RT-PCR) with specific primers for Tobacco mild green mosaic virus (TMGMV) (1) predicted to amplify a 530 bp of the coat protein region. From all samples, a RT-PCR product of the expected size was obtained and then sequenced. BLAST analysis of one sequence (GenBank Accession No. DQ460731) showed high levels of identity with TMGMV isolates, with more than 99% nucleotide identity with the DSMZ PV-112 isolate (GenBank Accession No. AJ429096). The symptomatology observed on pepper plants, the TMGMV RT-PCR assay, and the consensus of sequenced regions with TMGMV lead us to conclude that TMGMV was the causal agent of the diseased C. chinense plants. Although TMGMV has a wide plant host range occurring worldwide (1), to our knowledge, this is not only the first time TMGMV has been detected in Venezuela, but also the first report of TMGMV in C. chinense in Venezuela and the first reliable probe of the TMGMV seed transmission.

Reference: (1) J. Cohen et al. Ann. Appl. Biol. 138:153, 2001.