Molecular Characterization of Aphid Juveniles Through Mitochondrial Cytochrome Oxidase I (mtCOI) Partial Gene Barcoding

Abstract

The identification of aphid juveniles, particularly those for polyphagous species, is challenging even for expert taxonomists. Mitochondrial DNA sequences have been used for inter- and intra-specific differentiation between a wide range of metazoan invertebrates, including insects. In this study, we performed a cytochrome oxidase subunit I (COI) mitochondrial partial gene barcoding on juveniles of two main polyphagous Aphidini species widespread in Chlef Valley (Algeria), i.e. Aphis gossypii and Aphis spiraecola. The newly recorded species in Algeria Pterochloroides persicae was used as an out-group species. Results showed that mtCOI gene is an effective species-distinguishing molecular marker, as the populations of the three aphid specie were clustered together in accordance with their homologous species retrieved from NCBI GenBank database. In contrast, subspecies discrimination was not achieved. Mean intraspecific sequence divergence in Aphidinae subfamily ranged from 5.8% to 7%. However, the mean interspecific variation between subfamilies (Aphidinae and Lachnidae) was higher than 10%, ranging from 9.4% to 10.6%. Multiple sequence alignment highlighted two single nucleotide polymorphisms (SNPs) observed within populations of A. gossypii and A. spiraecola sequences.

Keywords:

Aphids, mtCOI, juvenile stage, interspecific identification, single nucleotide polymorphism.