Rapid and reliable species identification of Carposina sasakii from its morphological homologues, by MALDI-TOF mass spectrometry

Abstract

Rapid and accurate identification of pest species found on quarantine inspection is of great importance to prevent an economic loss of agricultural commodities. In this study, we tested MALDI-TOF mass spectrometry to discriminate the larvae of three morphologically similar pest species, Carposina sasakii, Grapholita molesta and Grapholita dimorpha, which usually found in Korean fruit exported to Asia and western countries. Unique mass spectra profile by MALDI-TOF MS covering a wide molecular mass range of 2000–20,000Da were produced from twelve reference samples for three species. The Principal Component Analysis and the heat map profile showed similar pattern within same species regardless of body part of a larvae, however showed clear discrimination between different species. This identification method can discriminate species within 15min with a relatively small sample sized 2mm3. It also can provide a simple well documented protocol and can be widely applied to identify pests that essentially needed an urgent identification such as quarantine inspection or health related pest monitoring to reduce an economic loss or to control the spread of the disease.