Rapid and highly sensitive detection of single nematode via direct MALDI Mass Spectrometry

For the first time, we demonstrate the feasibility for the use of MALDI-TOF MS for rapid, direct and sensitive detection of single adult root-knot nematode, Meloidogyne incognita and their second stage juvenile (J(2)). We have proposed simple pretreatment protocols and have demonstrated that the crushed and washed nematodes yielded better spectra. We also report the differentiation between the harmless and harmful stages of the nematode based on mass spectrometric profiling. Peaks at m/z 4350, 4692, 4933, 8725 were only present in the adult stages, while m/z 3220, 3433, 3485, 3830, 6540, 7444, 7770 were unique to the J(2) infective stage. The only common peak to both the phases was at m/z 3277. Thus, we show that MALDI-TOF MS can be used to differentiate between the infective and non-infective stage of the nematode and the detection sensitivity of MALDI-MS could be applied to a single nematode analysis.