The complete mitochondrial genome of the fall webworm, Hyphantria cunea (Lepidoptera: Arctiidae).

The complete mitochondrial genome (mitogenome) of the fall webworm, Hyphantria cunea (Lepidoptera: Arctiidae) was determined. The genome is a circular molecule 15 481 bp long. It presents a typical gene organization and order for completely sequenced lepidopteran mitogenomes, but differs from the insect ancestral type for the placement of tRNA(Met). The nucleotide composition of the genome is also highly A + T biased, accounting for 80.38%, with a slightly positive AT skewness (0.010), indicating the occurrence of more As than Ts, as found in the Noctuoidea species. All protein-coding genes (PCGs) are initiated by ATN codons, except for COI, which is tentatively designated by the CGA codon as observed in other lepidopterans. Four of 13 PCGs harbor the incomplete termination codon, T or TA. All tRNAs have a typical clover-leaf structure of mitochondrial tRNAs, except for tRNA(Ser)(AGN), the DHU arm of which could not form a stable stem-loop structure. The intergenic spacer sequence between tRNA(Ser)(AGN) and ND1 also contains the ATACTAA motif, which is conserved across the Lepidoptera order. The H. cunea A+T-rich region of 357 bp is comprised of non-repetitive sequences, but harbors several features common to the Lepidoptera insects, including the motif ATAGA followed by an 18 bp poly-T stretch, a microsatellite-like (AT)(8) element preceded by the ATTTA motif, an 11 bp poly-A present immediately upstream tRNA(Met). The phylogenetic analyses support the view that the H. cunea is closerly related to the Lymantria dispar than Ochrogaster lunifer, and support the hypothesis that Noctuoidea (H. cunea, L. dispar, and O. lunifer) and Geometroidea (Phthonandria atrilineata) are monophyletic. However, in the phylogenetic trees based on mitogenome sequences among the lepidopteran superfamilies, Papillonoidea (Artogeia melete, Acraea issoria, and Coreana raphaelis) joined basally within the monophyly of Lepidoptera, which is different to the traditional classification.

[Molecular phylogenetic relationships among species in the genus Sorghum based on partial Adh1 gene].

The genus Sorghum contains some important grain crops and economically important forage grasses as well as agricultural weeds. The goals of this study were to elucidate the phylogenetic relationships between Sorghum species and ascertain the taxonomy status of the quarantine weeds which provide bases for effective utilization of its germ resources on molecular breeding and improvement of crop qualities and thus provide important guidance for port detection. In the present study, total DNA from the seeds of 8 Sorghum species (four S. almum, two S. halepense, one S. silk and one S. sudanense)were extracted, and the partial Adh1 gene of about 2,000 bp in length were amplified by PCR using specific primers designed from conserved regions of Adh1 gene reported in the GenBank (AF050456) and sequenced. Based on these sequences and other 24 Adh1 sequences registered in the GenBank, the phylogenetic trees constructed by multiple methods (MP, ML, and NJ) with the corresponding Adh1 sequence of Cleistachne sorghoides as the outgroup shared almost the same topology. The results showed that: (1) there were obviously three lineages for the genus Sorghum. One included two subgenera Chaetosorghum and Heterosorghum, and another included subgenus Eusorghum, both of which consisted of 2n=20 and 2n=40 species with small chromosomes. Still another lineage contained the two subgenera Parasorghum and Stiposorghum with 2n=10 species and their polyploid relatives with relatively large chromosomes; (2) geographical divergence clearly existed in the S. almum; (3) S. purpureosericeum, S. versicolor, S. nitidum and S. leiocladum of subgenus Parasorghum clustered together, but S. matarankense, S. grande, and S. timorense of the same subgenus clustered with the species of subgenus Stiposorghum, showing closer relationship with subgenus Stiposorghum; (4) S. macrospermum was more closely related to S. laxiflorum than the other species of the genus Sorghum.