Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2007
Publication Date: July 28, 2007
Citation: Ling, K. 2007. The Population Genetics of Pepino Mosaic Virus in North America Greenhouse Tomatoes. Phytopathology. 97:S65. Technical Abstract: Pepino mosaic virus (PepMV), genus potexvirus, is an emerging disease in greenhouse tomato crops in Europe and North America. The genomes of more than 10 PepMV isolates have been completely sequenced. The sequenced European tomato isolates share high genome nucleotide sequence similarity (>98%). However, genetic diversity (~80%) has been observed in the US (US1 and US2) or Chilean isolates (Ch1 and Ch2). Understanding the genetic variability in a field population is crucial for the successful development of a sequence-based detection technique (e.g., RT-PCR) and for an effective disease management with resistance. During 2006, a survey was conducted on seven major greenhouse tomato facilities in the United States [Alabama (AL), Arizona (AZ), California (CA), Colorado (CO), and Texas (TX)] and Canada [British Columbia (BC) and Ontario (ON)]. A total of 37 field isolates of PepMV were collected during this survey and used to study their genetic types through nucleotide sequence comparisons. Using a consensus primer pair (KL05-13 and KL05-14) in RT-PCR, a 191 bp sequence fragment in the TGB3 region was generated from all of the collected PepMV isolates. These RT-PCR products were cloned into TOPO TA cloning vector and at least two clones from each isolate were sequenced. The generated nucleotide sequences were evaluated against the Genbank database (Blastn) and their phylogenetic relationship analyzed. The results showed that almost all the North American isolates evaluated belonged to the European tomato strain. However, both European-like and US-like isolates co-existed in a large commercial greenhouse tomato facility in Arizona. Biological significance of this single vs mixed infection of different PepMV isolates in disease diagnosis and control will be discussed.