Issue Environ. Biosafety Res. Volume 5, Number 1, January-March 2006 Page(s) 47 - 56 DOI 10.1051/ebr:2006013 Published online 19 September 2006

Environ. Biosafety Res. 5 (2006) 47-56
DOI: 10.1051/ebr:2006013

An attempt to identify recombinants between two sobemoviruses in doubly infected oat plants

Merike Meier and Erkki Truve

Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 19086 Tallinn, Estonia

(Received December 30, 2005; accepted May 30, 2006; published online: 19 September 2006)

Abstract
Recombination in RNA viruses is considered to play a major role as a driving force in virus variability to counterbalance loss in fitness that can be due to the accumulation of detrimental mutations. Studies on mixed infections are pertinent for understanding the role of recombination in virus evolution. They also provide important baseline information for studying the biosafety of plants expressing viral sequences. To investigate the possibility of RNA recombination occurrence between two sobemoviruses under little or no selection pressure, we co-infected test plants with Cocksfoot mottle virus (CfMV) and Ryegrass mottle virus (RGMoV). CfMV and RGMoV were selected because of their overlapping host range and geographical distribution. First, symptom development of both viruses in barley (Hordeum vulgare) and oat (Avena sativa) was examined. Both viruses generated quite strong infection symptoms in oat, but synergism was not detected. RGMoV was lethal for barley, whereas CfMV infection in barley was nearly symptomless. RT-PCR analysis revealed 100% infection with both viruses in oat but not in barley. Therefore, an RNA recombination study of CfMV and RGMoV was performed in oat. 105 plants were co-inoculated with both viruses and putative recombinational hot spot regions were screened for recombination events by RT-PCR analysis at a sensitivity level down to 0.1-100 pg of viral genomic RNA. No recombination events between the two sobemoviruses were detected.

Key words: Cocksfoot mottle virus / Ryegrass mottle virus / RNA recombination / RT-PCR

Corresponding author: Erkki Truve erkki.truve@ttu.ee

© ISBR, EDP Sciences 2006

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