Optimisation of a Rapid CTAB Protocol for High-Quality DNA Extraction From Polysaccharide-Rich Plant Tissues

Abstract

The cetyltrimethylammonium bromide (CTAB) method has been the workhorse of plant DNA extraction for more than three decades, yet it is notorious for failing on tissues loaded with polysaccharides and polyphenols. Mucilage, gums, pectins and storage carbohydrates co-precipitate with nucleic acids, turn pellets into glassy gels, inhibit polymerases and restriction enzymes, and distort absorbance readings. This narrative review asks what the published literature says about making a CTAB protocol both rapid and reliable for such tissues. It draws on the original CTAB papers, on the many modifications proposed for difficult species, and on work about PCR inhibition and the assessment of DNA quality, and it reports no new laboratory data. Optimisation emerges as a matter of balance rather than of any single magic additive: salt concentration, polyvinylpyrrolidone, reducing agents, chloroform steps and precipitation conditions each solve one problem while risking another, and speed gained by shortening a step is often lost again in repeated extractions. Quality checks based on absorbance ratios are useful but easily misread, and amplification of the intended target remains the decisive test. The review closes with a short list of what a convincing optimisation report should contain.