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DNA Extraction

Release time:2013.01    Source:

High-quality genomic DNA is an important prerequisite for accurate identification using DNA barcoding. As such, DNA extraction of herbal materials must be performed carefully, quickly and using good sterile technique to avoid DNA degradation and contamination between samples. Generally, the surface of herbal materials was first wiped with 75% ethanol, and20-100 mg of the herbal materials was rubbed for 2 min at a frequency of30 times/s in a FastPrep bead mill (Retsch MM400, Germany). Totalgenomic DNA was isolated from the crushed materials using the PlantGenomic DNA Kit, according to themanufacturer's instructions.
Here, we summarize the key points to consider in the DNA extraction of different herb materials.
Root, rhizome, stem, and cortex material
Generally, the surface of herbal material iscleanedwith 75% alcohol prior to being ground to a fine powder in liquid nitrogen for DNA extraction. In most cases, root and rhizome-based herbs have high contents of polysaccharides and polyphenols. These must be removed using polyvinylpyrrolidone (PVP) and β-mercaptoethanol during the early stages of DNA extraction.Root and rhizome-based herbs are rich in fiber and plant energy stores including starches, and often the amount of material and corresponding extraction chemicals must be increased. Cortex herbs contain abundant parenchyma and fiber; thus, the dosage of plant starting material, PVP, and β-mercaptoethanol must be increased accordingly for DNA extraction.
Leaf and flower material
Leaves and flowers are generally low in fibrous and interfering secondary metabolites and, as such, tend to be the easiest tissues to extract high-quality DNA.
Fruit and seed material
Fruit and seed-based herbs often have high oil content, which can hamper grinding and result in low DNA yields. Thus, the amount of starting material must be increased. Acetone may be used in extracting milled materials to remove liposoluble phenolic compounds.

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