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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 4/10/2005 Publication Date: 4/10/2005 Citation: Ling, K. 2005. High sequence homology between pepino mosaic virus isolates from Chile and the USA [abstract]. Second Joint Conference of the International Working Groups on Legume (IWGLV) and Vegetable Viruses (IWGVV). p. 20 Available: http://www.ifa.to.cnr.it/vvwg/documents/Abstracts_Rev.pdf. Interpretive Summary: Technical Abstract: Pepino mosaic virus (PepMV), a Potexvirus, was first observed to infect greenhouse tomatoes in the Netherlands and the U. K. in 1999. In recent years, it has spread throughout Europe and the Americas. In general, Potexviruses are not regarded as seed borne. However, our preliminary study indicated that PepMV is seed borne in tomato. Most of the PepMV European isolates share high genome sequence similarity, while two recently sequenced U.S. isolates (US-1 and US-2) (GenBank accessions AY509926 and AY509927) are more divergent (from each other and from European isolates). This suggests that the U.S. isolates did not originate in Europe. Using commercial seed that was originally produced in Chile as inoculum, several tomato plants were mechanically inoculated with PepMV. The PepMV-infected plants were maintained in a growth chamber for isolation and containment. A genome sequencing project was initiated using tissues collected from a single PepMV-infected plant. The sequencing strategy was based on RT-PCR with consensus sequence primers flanking the coat protein gene and subsequently with specific primers extending towards the 5'and 3' directions of the virus genome. The RT-PCR products were cloned into pCR4-TOPO (Invitrogen) for sequencing. The 5' terminal sequence was determined with RT-PCR using primers against polyadenylated dsRNA. The sequencing data were generated with a dye-terminator cycle sequencing on a Beckman-Coulter CEQ8000 sequencer. The sequencing data indicated the presence of two distinct variants of genome sequence. One isolate (Chile-1) has high nucleotide sequence homology (~98%) to that of US-1 while the other isolate (Chile-2) has a similar high sequence homology to US-2. Like the US isolates, the Chilean isolates are divergent from each other (~83% nucleotide sequence homology). This strong similarity in genome sequences between the two US and Chilean isolates suggests that they might share a common source of origin. Genome sequencing data of these two Chilean isolates and their phylogenetic relationship will be presented. |
