Molecular identification of Bactrocera passiflorae (Diptera: Tephritidae): challenge and solution for DNA barcoding

Fruit flies cause significant damage to crop and fruit production worldwide. Therefore it is essential to identify these organisms to species level, however, immature stages are often impossible to be identified morphologically, thus the application of DNA barcoding has greatly assisted in species identification. Nuclear, mitochondrial pseudo-COI (NUMT) can be co-amplified with mitochondrial DNA when using generic primers and therefore impair the efficacy of DNA barcoding. This study detected two types of NUMTs from B. passiflorae, one of them is novel. Therefore the new finding will assist future species identification by avoiding misidentification using ambiguous NUMT sequences. In addition, this study have developed primers to target the COI gene of B. passiflorae, not the NUMT copies. The newly designed primers have demonstrated its efficiency in amplifying the Mt-COI of B. passiflorae and can be used in routine diagnostics.