Rapid and sensitive detection of <Emphasis Type="Italic">Meloidogyne mali</Emphasis> by loop-mediated isothermal amplification combined with a lateral flow dipstick

Meloidogyne mali Itoh, Ohshima & Ichinohe, 1969 is a polyphagous root-knot nematode that infects a wide range of host plants and is subject to phytosanitary restrictions in many countries, including China. In this study, we integrated the loop-mediated isothermal amplification (LAMP) technique with visual detection by a lateral flow dipstick (LFD) and developed an accelerated LAMP-LFD method for the rapid identification of M. mali, targeting the internal transcribed spacer regions and 5.8S ribosomal DNA sequence (ITS-5.8S). The entire test could be performed within 45 min, including 35-min LAMP amplification, 5-min hybridization, and 3–5-min visualization on LFD. The detection limit of this method was 2-pg bulked M. mali gDNA per reaction, and the equivalent of 1‰ single female adult or 1% single second-stage juvenile (J2) could be detected. It is recommended that DNA is extracted from single J2 isolated from soil samples by the modified Baermann funnel method or from an adult female from galls. Based on this, the field sensitivity and specificity of this LAMP-LFD method for the detection of M. mali in field soil samples were both 100% compared to traditional microscopic observation. These results indicate that the LAMP-LFD method is rapid, sensitive, accurate, and simple, and would be applicable for the routine monitoring of phytosanitary M. mali.