BackgroundRapid RNA extraction is commonly performed with commercial kits, which are very expensive and can involve toxic reagents. Most of these kits can be used with healthy plant tissues, but do not produce consistently high-quality RNA from necrotic fungus-infected tissues or fungal mycelium.FindingsWe report on the development of a rapid and relatively inexpensive method for total RNA extraction from plants and fungus-infected tissues, as well as from insects and fungi, based on guanidine hydrochloride buffer and common DNA extraction columns originally used for the extraction and purification of plasmids and cosmids.ConclusionsThe proposed method can be used reproducibly for RNA isolation from a variety of plant species. It can also be used with infected plant tissue and fungal mycelia, which are typically recalcitrant to standard nucleic acid extraction procedures.