A valid measure to eliminate the influence of polysaccharides and polyphenols in recalcitrant longan (Dimocarpus longan L.) during DNA isolation

Large amounts of polysaccharides, polyphenols, tannins, proteins, and other secondary metabolites in recalcitrant longan leaves make it difficult to obtain high quality genomic DNA during extraction. To obtain good quality of nucleic acids from local longan leaves and for its downstream applications, a new protocol was developed. It consists of rapid isolation of stable nuclei, which hinders covalent interactions with phenolics, followed by DNA extraction. The yield and quality of the resulting DNA were satisfactory and suitable for PCR analysis and digestion with a restriction enzyme. Here, a valid combination measure (β-mercaptoethanol, PVP40 and PVPP were used at different stages) was created to eliminate the influence of polysaccharides and polyphenols in recalcitrant longan during DNA extraction, which will facilitate the development of molecular quantitative genetics of longan.   Key words: Longan, extraction buffer, DNA isolation, PCR products. †These authors contributed equally to this work.