Characterization of the Complete Mitochondrial Genome of Leucoma salicis (Lepidoptera: Lymantriidae) and Comparison with Other Lepidopteran Insects

Abstract

The complete mitochondrial genome (mitogenome) of Leucoma salicis (Lepidoptera: Lymantriidae) was sequenced and annotated. It is a circular molecule of 15,334 bp, containing the 37 genes usually present in insect mitogenomes. All protein-coding genes (PCGs) are initiated by ATN codons, other than cox1, which is initiated by CGA. Three of the 13 PCGs had an incomplete termination codon, T or TA, while the others terminated with TAA. The relative synonymous codon usage of the 13 protein-coding genes (PCGs) was consistent with those of published lepidopteran sequences. All tRNA genes had typical clover-leaf secondary structures, except for the tRNA^Ser (AGN), in which the dihydrouridine (DHU) arm could not form a stable stem-loop structure. The A + T-rich region of 325 bp had several distinctive features, including the motif 'ATAGA' followed by an 18 bp poly-T stretch, a microsatellite-like (AT)₇ element, and an 11-bp poly-A present immediately upstream of tRNA^Met. Relationships among 32 insect species were determined using Maximum Likelihood (ML), Neighbor Joining (NJ) and Bayesian Inference (BI) phylogenetic methods. These analyses confirm that L. salicis belongs to the Lymantriidae; and that Lymantriidae is a member of Noctuoidea, and is a sister taxon to Erebidae, Nolidae and Noctuidae, most closely related to Erebidae.