Development of a loop-mediated isothermal amplification for rapid diagnosis of Aphelenchoides ritzemabosi

To establish the amplification and detection system for the chrysanthemum foliar nematode (CFN), Aphelenchoides ritzemabosi, the loop-mediated isothermal amplification (LAMP), which includes two external primers (F3/B3), two inner primers (FIP/BIP) and one loop primer (LF), was designed based on the CFN 18S ribosomal RNA gene. The DNA samples were amplified by LAMP primers using isothermal amplification (65 degrees C). The amplified products were detected by electrophoresis and visual inspection of fluorescent dyes. Detection of CFN in a sample was confirmed when the electrophoresis results show a DNA ladder or the mixtures in the tubes showed green fluorescence. The results showed that the LAMP method could not only detect and identify a single female, male, juvenile and egg of CFN but also directly detect CFN in mixed nematode species samples and plant tissue samples. The sensitivity of the LAMP assay was 100-fold dilution of single nematode DNA.