A new method for extraction of double-stranded RNA from plants

The occurrence of high molecular weight double-stranded RNA (dsRNA) in plants is associated with the presence of RNA viruses. DsRNA is stable, can be extracted easily from the majority of plant species and provides an excellent tool for characterization of novel viruses that are recalcitrant to purification. Several protocols have been developed for dsRNA purification, the majority of which are based on extraction with phenol and chloroform. We have developed a protocol for dsRNA extraction based on a lithium salts buffer that does not require organic solvents other than alcohols. The method yields comparable amount of dsRNA to protocols described previously and yields consistently dsRNA from Vaccinium hosts that have been recalcitrant to dsRNA purification using traditional protocols. The quality of the dsRNA purified is such that it can be used for downstream enzymatic reactions including reverse transcription-polyrnerase chain reaction and cloning. (C) 2008 Elsevier B.V. All rights reserved.