Multiplexing in Loop-mediated Isothermal Amplification (LAMP) for Efficient Detection of Genetically Modified Organisms (GMOs)

Isothermal nucleic acid amplification refers to the amplification of nucleic acid using specific primers at a constant temperature where no separated denaturation, annealing and extension steps are required. Isothermal nucleic acid amplification techniques (iNAATs) such as loop-mediation isothermal amplification (LAMP) and recombinase polymerase amplification (RPA) have been used in GMO detection (Singh et al. 2019).

- Monika Singh, Raghavendra Aminedi, Deepa Pal, Kushaldeep Kaur and Amit Kumar Singh

LAMP is preferred over other iNAATs because of its higher amplification efficiency, excellent specificity and sensitivity. LAMP was first introduced by Notomi et al. (2000) where amplification of template DNA is carried out at a constant temperature using four different primers recognizing six distinct regions on the target sequence. F3, B3 (outer primer pair) targeting the sequences of sense and antisense strands initiates the LAMP reaction, which proceeds at a constant temperature Further strand displacement DNA synthesis is primed using FIP, BIP (inner primer pair).

Since the past decade, LAMP-based assays detecting a single GM target or transgenic element has been reported using different detection systems and alternate platforms including a heating block, thermal cycler or real-time isothermal amplification system such as the Genie II, as reviewed by Singh et al., 2019. Based on the detection systems, LAMP can be categorized as end-point LAMP (visual detection) and real-time LAMP (detection based on florescence measurement as amplification and annealing curves), as shown in Figure 1.