A Universal RNA Extraction Method for High-Polyphenol Plant Tissues

Isolating high-quality RNA from plant tissues rich in polyphenols and polysaccharides presents a significant challenge in molecular research. This study details a robust and reproducible method for extracting total RNA from high-polyphenol plant tissues, including grapes, bananas, and tomatoes. The protocol begins with 0.5 g of flash-frozen tissue ground in liquid nitrogen, followed by extraction with a hot CTAB buffer, phase separation using chloroform, and RNA precipitation with lithium chloride. Ethanol washes ensure purity before resuspension in DEPC-treated water. Key reagents such as CTAB, PVP, EDTA, NaCl, spermidine, and β-mercaptoethanol enhance RNA yield and quality. Completed within approximately 36 hours, the protocol yields between 120 and 2120 µg of RNA per 500 mg of banana tissue, with leaf tissues generally providing the highest amounts. This optimized method delivers high-integrity RNA, making it well-suited for diverse downstream molecular applications.