ENVIRONMENTAL IMPACT ASSESSMENT OF TRANSGENIC PLUMS ON THE DIVERSITY OF PLUM POX VIRUS POPULATIONS

Plum pox virus (PPV) is considered as the most detrimental virus of stone fruit-trees, causing serious yield losses. Transgenic plums were produced and released in field. In order to analyze the environmental effects related to the release of virus-resistant transgenic crops we studied the diversity of PPV populations in GM plum clones containing the PPV coat protein (CP) gene. We compared the serological and molecular variability of PPV detected in the transgenic trees versus those found in conventional plums. PPV strains were serologically determined by TAS-ELISA using PPV-D and PPV-M specific monoclonal antibodies. Molecular strain typing was performed targeting three genomic regions (Cter) CP, (Cter) NIb-(Nter) CP and CI. RFLP analysis was used to distinguish the two major strains, D and M based on an Rsa I polymorphism located in (Cter)CP. PCR products spanning (Cter) CP and (Cter) NIb-(Nter) CP regions were sequenced. The results revealed that there was no significant difference between PPV isolates from transgenic and conventional plums. This study confirmed that the transgenic plums evaluated in this report do not represent an environmental risk through the production of any emerging PPV variants.