Diagnosis of plant-parasitic nematodes using loop-mediated isothermal amplification (LAMP): A review

Plant-parasitic nematodes (PPNs) cause substantial damage to agricultural and horticultural crops around the world. The early, accurate and rapid detection of PPNs at field level is the most important step to manage these pests, but remains a challenge for researchers. Loop-mediated isothermal amplification (LAMP) has emerged as a robust, rapid and sensitive method for point-of-service detection and diagnosis of plant pathogens such as bacteria, fungus, virus and nematodes. The present review summarises and analyses the LAMP assays developed for the detection and diagnosis of various important PPNs. Different gene targets such as SSU, 5.8S, LSU, ITS-1, ITS-2, D2-D3, IGS-1 and IGS-2 regions of the rRNA, syg-2 and pel-3 genes have been used for the development of the highly sensitive, species-specific or genus-specific LAMP assays for various PPNs. The LAMP assays are superior to PCR based assays as they are faster, more sensitive and can detect nematode DNA in up to femtogram quantities from the soil, plant tissue, preserved nematode samples or nematode genomic DNA stabilised on cellulose cards. The results of the LAMP assays can be visualised in the reaction tube by DNA intercalating dyes, observation of sample turbidity, by gel electrophoresis, and through lateral flow assays. Presently the LAMPbased assays are gaining popularity as the method of choice for point-of-care detection and diagnosis of various PPNs.