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RNAi-mediated resistance to Potato spindle tuber viroid in transgenic tomato expressing a viroid hairpin RNA construct |
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| Authors: | NORA SCHWIND,MICHÈ LE ZWIEBEL,ASUKA ITAYA,BIAO DING,MING-BO WANG,GABI KRCZAL, MICHAEL WASSENEGGER |
| Affiliation: | RLP Agroscience GmbH, AlPlanta-Institute for Plant Research, Breitenweg 71, 67435 Neustadt, Germany; Department of Plant Cellular and Molecular Biology and Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA; CSIRO Division of Plant Industry, PO Box 1600, Canberra, ACT 2601, Australia |
| Abstract: | Because of their highly ordered structure, mature viroid RNA molecules are assumed to be resistant to degradation by RNA interference (RNAi). In this article, we report that transgenic tomato plants expressing a hairpin RNA (hpRNA) construct derived from Potato spindle tuber viroid (PSTVd) sequences exhibit resistance to PSTVd infection. Resistance seems to be correlated with high-level accumulation of hpRNA-derived short interfering RNAs (siRNAs) in the plant. Thus, although small RNAs produced by infecting viroids [small RNAs of PSTVd (srPSTVds)] do not silence viroid RNAs efficiently to prevent their replication, hpRNA-derived siRNAs (hp-siRNAs) appear to effectively target the mature viroid RNA. Genomic mapping of the hp-siRNAs revealed an unequal distribution of 21- and 24-nucleotide siRNAs of both (+)- and (–)-strand polarities along the PSTVd genome. These data suggest that RNAi can be employed to engineer plants for viroid resistance, as has been well established for viruses. |
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