title: Biosafety considerations of RNAi-mediated virus resistance in fruit-tree cultivars and in rootstock.
abstract: A major application of RNA interference (RNAi) is envisaged for the production of virus-resistant transgenic plants. For fruit trees, this remains the most, if not the only, viable option for the control of plant viral disease outbreaks in cultivated orchards, due to the difficulties associated with the use of traditional and conventional disease-control measures. The use of RNAi might provide an additional benefit for woody crops if silenced rootstock can efficiently transmit the silencing signal to non-transformed scions, as has already been demonstrated in herbaceous plants. This would provide a great opportunity to produce non-transgenic fruit from transgenic rootstock. In this review, we scrutinise some of the concerns that might arise with the use of RNAi for engineering virus-resistant plants, and we speculate that this virus resistance has fewer biosafety concerns. This is mainly because RNAi-eliciting constructs only express small RNA molecules rather than proteins, and because this technology can be applied using plant rootstock that can confer virus resistance to the scion, leaving the scion untransformed. We discuss the main biosafety concerns related to the release of new types of virus-resistant plants and the risk assessment approaches in the application of existing regulatory systems (in particular, those of the European Union, the USA, and Canada) for the evaluation and approval of RNAi-mediated virus-resistant plants, either as transgenic varieties or as plant virus resistance induced by transgenic rootstock.
authors.affiliation: New Partnership for Africa's Development (NEPAD) Agency, Africa Biosafety Network of Expertise (ABNE), University of Ouagadougou, 06 BP 9884, Ouagadougou 06, Burkina Faso.
authors.forename: Godwin Nana Yaw
authors.initials: GN
authors.lastname: Lemgo
authors.forename: Silvia
authors.initials: S
authors.lastname: Sabbadini
authors.forename: Tiziana
authors.initials: T
authors.lastname: Pandolfini
authors.forename: Bruno
authors.initials: B
authors.lastname: Mezzetti
mesh_terms: D002170:Canada; D005062:European Union; D005638:Fruit / Q000235:genetics* / Q000821:virology; D005818:Genetic Engineering; D010935:Plant Diseases / Q000235:genetics* / Q000821:virology; D010942:Plant Viruses / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000821:virology; D034622:RNA Interference; D012328:RNA Viruses / Q000235:genetics; D014197:Trees / Q000235:genetics* / Q000821:virology