DNA Extraction from Plant Tissue

Challenges with plants

Plant cells contain polysaccharides, phenolics, and cellulose that interfere with DNA quality. Protocol choice depends on tissue type (leaf, seed, woody stem).

CTAB method overview

1. Grind frozen tissue in CTAB buffer with high salt.
2. Incubate at 65°C to lyse cells and denature proteins.
3. Extract with chloroform-isoamyl alcohol to separate phases.
4. Precipitate DNA with isopropanol; wash with ethanol; dissolve in TE buffer.

Quality assessment

Run aliquot on agarose gel — high molecular weight band without smear indicates good quality. Measure A260/A280 ratio (~1.8–2.0) on spectrophotometer.

Storage

Short term: 4°C. Long term: −20°C or −80°C. Avoid repeated freeze-thaw cycles.