RNA Isolation From High-Phenolic Freeze-Dried Tea (Camellia sinensis) Leaves

With minor modifications, we applied a previously reported RNA isolation protocol that used guanidine hydrochloride to leaves of lyophilized (freeze-dried) tea (Camellia sinensis). Plant tissue must be preserved in its collected state, especially when genome-wide expression profiles are studied. Fresh leaf tissues cannot feasibly be transferred at ultra-low temperatures from natural habitats to the laboratory. We explored the use of lyophilized tissue for RNA isolation from tea leaves. High yields of RNA ($\sim 500 \mu g/g$ dry weight of leaf tissue) were obtained, and the RNA was suitable for all molecular biology methods tested, including Northern blotting, reverse transcription, and microarray analysis. We demonstrated that RNA obtained from freeze-dried leaf tissue was high quality, undegraded, and useful for all downstream applications