Tempo and Mode of Plant RNA Virus Escape from RNAi- Mediated Resistance
A biotechnological application of artificial microRNAs (amiR) is the generation of plants resistant to virus infection. This resistance has proven to be highly effective and sequence-specific. However, before these transgenic plants can be deployed in the fields, it is important to evaluate the like...
| Autores: | , , , , , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/48714 |
| Acceso en línea: | http://hdl.handle.net/10261/48714 |
| Access Level: | acceso abierto |
| Palabra clave: | Cucumber Mosaic Virus Antiretroviral resistance Viral-RNA Type-1 |
| Sumario: | A biotechnological application of artificial microRNAs (amiR) is the generation of plants resistant to virus infection. This resistance has proven to be highly effective and sequence-specific. However, before these transgenic plants can be deployed in the fields, it is important to evaluate the likelihood of emergence of resistance-breaking mutants. Two issues are of particular interest: (i) whether such mutants can arise in non-transgenic plants that may act as reservoirs; and (ii) whether suboptimal expression of the transgene, resulting in sub-inhibitory concentrations of the amiR would favor the emergence of escape mutants. To address the first issue, we experimentally evolved independent lineages of Turnip mosaic virus (TuMV, family Potyviridae) in fully susceptible wild-type Arabidopsis thaliana plants and then simulated the spill over of the evolving virus to the fully resistant A. thaliana transgenic plants. To address the second issue, the evolution phase took place in transgenic plants that expressed the amiR at sub-inhibitory concentrations. Our results show that TuMV populations replicating in susceptible hosts accumulated resistance-breaking alleles that resulted in overcoming the resistance of fully resistant plants. The rate at which resistance was broken was 7 times faster for TuMV populations that experienced sub-inhibitory concentrations of the antiviral amiR. Molecular characterization of escape alleles showed that all contained at least one nucleotide substitution in the target sequence, generally a transition of the G-to-A and Cto- U types, with many instances of convergent molecular evolution. To better understand the viral population dynamics taking place within each host, as well as to evaluate relevant population genetic parameters, we performed in silico simulations of the experiments. Together, our results contribute to the rational management of amiR-based antiviral resistance in plants. |
|---|