Loop-mediated isothermal amplification (LAMP).

Amplification methods that work under isothermal conditions have been developed as alternatives to polymerase chain reaction (PCR). One approach to isothermal amplification is to generate products containing self-complementary regions that form single-stranded loops to which primers can bind. This chapter describes, including the advantages and disadvantages, the loop-mediated isothermal amplification (LAMP), which is the most common method using this approach. LAMP uses two pairs of primers (internal and external) and a DNA polymerase with strand-displacing activity to generate amplification products containing loops. One feature of LAMP as a nucleic acid amplification method that is potentially useful in the detection of plant pathogens (including viruses, bacteria and fungi) is the greater tolerance to inhibitors of the DNA polymerase used for LAMP in comparison with those used for conventional PCR. LAMP amplification products can be visualized by gel electrophoresis, in the same way as the products of other nucleic acid amplification methods. LAMP is highly efficient, and the amount of product generated also allows the use of other endpoint detection methods, which would be insuficiently sensitive to detect the smaller amounts of product generated by amplification methods such as PCR. The efficiency of amplification achieved using LAMP distinguishes this method from many other amplification techniques but also constitutes a significant potential disadvantage of the method, as the potential of carry-over contamination with amplification products is substantially higher than for other methods. However, relatively simple steps can be taken to mitigate this risk.