DNA extraction from plants for disease analysis

Each year, diseases that affect plants cause losses of approximately 220 billion dollars in the agricultural industry worldwide. The FAO (Food and Agriculture Organization) of the United Nations estimates that more than 30% of world agricultural production is lost annually due to plant pathogens (fungi, bacteria and viruses) and pests, entailing consequences to the food supply.

For the detection of diseases that affect plants, molecular methods involving nucleic acid amplification are the most widely used. Briefly, these methods comprise three main steps: nucleic acid extraction and purification; amplification; and finally detection.

What does it consist of?

In greater detail, for DNA extraction and purification, approximately 100 mg of homogenate of the plant to be analyzed are lysed, using different lysis buffers.

The lysed sample is deposited in an extraction column attached to a 2 ml capacity collection tube, and the DNA is isolated from the rest of the molecules. To do this, steps of adding different reagents (wash buffers and elution buffer) are alternated with steps of centrifugation at 11,000 G for 1 or 2 minutes.

As a final result of this process, an elution containing the DNA of the plant of interest is obtained. Then, as indicated above, the isolated DNA is amplified using different techniques, the most used being PCR and its variants, such as RT-PCR.

Finally, the last step in the disease identification process is the detection and quantification of amplicons; processes for which techniques such as qPCR are used.

Diseases that affect plants are responsible for large economic losses in the agricultural industry, and therefore it is especially important to analyze them. For the first step of this analysis, which is the extraction and purification of DNA from plant cells, centrifugation is essential.