Detection and quantification of rice white tip nematode, Aphelenchoides besseyi Christie, 1942 (Aphelenchida:Aphelenchoididae) from rice

Rice is essential food source for more than %50 of world population, particulary for developing countries. Rice white tip nematode, Aphelenchoides besseyi Christie, 1942 causes economically yield losses in rice. Aphelenchoides besseyi has been on the quarantine list since 1981, according to the European Plant Protection Organization (EPPO/OEPP). Since rice white tip nematode is a seed-borne pathogens, it spreads rapidly by means of infected seeds. Therefore, rapid and accurate identification of A. bessseyi is necessary for effective control of nematode. In this study, a TaqMan probe assay based on small subunit rDNA region of A. besseyi was developed to identify A. besseyi. As a result, all A. besseyi populations showed an amplication curve and Ct values as expected using the TaqMan but the probe did not show any amplication curve from other related Aphelenchoides spp. species and plant-parasitic nematodes. Dilutions series of genomic DNA obtained from one A. besseyi juvenil was detected until 0.0005 pg genomic DNA and low detection limit of plasmid DNA was until 9.3X101 gene copies. All developmental stages of A. besseyi were detected using TaqMan probe. In addition, The TaqMan assay was directly identified alive A. besseyi without DNA isolation and infected rice tissues. We developed a scala for estimate of A. besseyi quality in rice seed and paddy using real-time PCR assay. Results showed rapid and accurate identification and quantification of A. besseyi. Findings can be used for seed certification and quarantine approaches.