Authors
W. S. Tsai, AVRDC--The World Vegetable Center, Shanhua, Tainan, 74151 Taiwan;
I. K. Abdourhamane, AVRDC Subregional Office for West and Central Africa, AVRDC s/c ICRISAT, BP320, Bamako, Mali, and
L. Kenyon, AVRDC--The World Vegetable Center, Shanhua, Tainan, 74151 Taiwan
The aphid-transmitted Pepper veinal mottle virus (PVMV; genus Potyvirus, family Potyviridae) has been reported as causing an epidemic in solanaceous crops, including eggplant, pepper, and tomato in Africa (4). In West Africa, PVMV has been detected in Senegal, Sierra Leone, Ivory Coast, Ghana, Togo, Burkina Faso, and Nigeria (2). In April 2009, leaf yellowing, mosaic, mottle, and curling symptoms indicative of viral infection were common on tomato (Solanum lycopersicum) and pepper (Capsicum annuum) plants in home gardens and fields in Mali. Symptomatic leaf samples were collected from two sweet pepper and two tomato plants from Baguineda, four tomato plants and one chili pepper plant in Kati, and three chili pepper plants from Samanko. All samples except two chili pepper from Samanko and two sweet pepper and two tomato from Baguineda tested positive for begomovirus by PCR with primers PAL1v1978/PAR1c715 (3). PVMV was detected by double-antibody sandwich (DAS)-ELISA using PVMV antibody (DSMZ, Braunschweig, Germany) in both Baguineda sweet pepper, one Baguineda tomato, and one Samanko chili pepper sample. Three PVMV ELISA-positive samples, one each of sweet pepper, chili pepper, and tomato, were also confirmed by reverse transcription (RT)-PCR and sequencing. The expected 1.8-kb viral cDNA was amplified from all three samples using the potyvirus general primer Sprimer1 (5′-GGNAAYAAYAGHGGNCARCC-3′), which was modified from the Sprimer (1) as upstream primer, and Oligo(dT) (5′-GCGGGATCCCTTTTTTTTTTTTTTTTTT-3′) as downstream primer. The sequences obtained from chili pepper (GenBank Accession No. GQ918274), sweet pepper (GenBank Accession No. GQ918275), and tomato (GenBank Accession No. GQ918276) isolates, excluding the 3′ poly-A tails, were each 1,831 nucleotides (nt) long, comprising the 3′-terminal of the NIb region (1 to 642 nt), the coat protein region (643 to 1,455 nt), and the 3′-untranslated region (1,456 to 1,831 nt). The sequences shared between 99.3 and 99.5% nucleotide identity with each other. A comparison of these sequences with corresponding sequences of potyviruses in GenBank revealed they had greatest nucleotide identity (96.5 to 96.6%) with a tomato isolate of PVMV from Taiwan (PVMV-TW; GenBank Accession No. EU719647), between 81.4 and 95.9% identity with other PVMV isolates, and only as much as 67.2% identity with other potyvirus isolates. Analysis of coat protein regions alone also revealed high nucleotide (96.6 to 96.8%) and amino acid (99.3 to 99.6%) identity with PVMV-TW. The PVMV Baguineda tomato isolate caused mosaic and mottle symptoms on tomato (line CLN1558A) and pepper (cv. Early Calwonder) plants following mechanical inoculation. To our knowledge, this is the first report of PVMV infecting plants in Mali and reinforces the need to take this virus into consideration when breeding tomato and pepper for this region.
References: (1) J. Chen et al. Arch. Virol. 146:757, 2001. (2) C. Huguenot et al. J. Phytopathol. 144:29, 1996. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) G. Thottappilly, J. Phytopathol. 134:265, 1992.
