A method for isolating functional RNA from callus of Dendrobium candidum contented rich polysaccharides.

Isolation of high-quality RNA from Dendrobium candidum is particularly difficult. D. candidum contains considerable amounts of polysaccharides that coprecipitate with RNA, which render RNA unsuitable for either cDNA synthesis and/or PCR amplification. In this paper, a rapid and efficient method was described for functional RNA isolation from the callus of D. candidum. The procedure included: (i) an extraction with phenol and isopropyl alcohol, to remove proteins and polyphenols; (ii) purifications by lithium chloride, pre-cooled (-20 degrees C) ethanol successively to remove polysaccharides. The method resulted in high-quality RNA suitable for DDRT-PCR and cDNA library analysis finally.