RNAi-mediated resistance to Potato spindle tuber viroid in transgenic tomato expressing a viroid hairpin RNA construct.
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.
Schwind
Nora
N
RLP Agroscience GmbH, AlPlanta-Institute for Plant Research, Neustadt, Germany.
Zwiebel
Michèle
M
Itaya
Asuka
A
Ding
Biao
B
Wang
Ming-Bo
MB
Krczal
Gabi
G
Wassenegger
Michael
M
D015152:Blotting, Northern; D015139:Blotting, Southern; D020090:Chromosome Segregation; D015967:Gene Expression Regulation, Viral; D007113:Immunity, Innate / Q000276:immunology; D018551:Solanum lycopersicum / Q000235:genetics / Q000821:virology*; D009690:Nucleic Acid Conformation; D010935:Plant Diseases / Q000235:genetics / Q000821:virology*; D035281:Plant Tubers / Q000821:virology*; D010942:Plant Viruses / Q000235:genetics*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D014772:Viroids / Q000737:chemistry / Q000235:genetics* / Q000502:physiology
D034741:RNA, Small Interfering; D012367:RNA, Viral