The hoverflies Episyrphus balteatus and Eupeodes corollae (Diptera: Muscomorpha: Syrphidae) are important natural aphid predators. We obtained mitochondrial genome sequences from these two species using methods of PCR amplification and sequencing. The complete Episyrphus mitochondrial genome is 16,175 bp long while the incomplete one of Eupeodes is 15,326 bp long. All 37 typical mitochondrial genes are present in both species and arranged in ancestral positions and directions. The two mitochondrial genomes showed a biased A/T usage versus G/C. The cox1, cox2, cox3, cob and nad1 showed relatively low level of nucleotide diversity among protein-coding genes, while the trnM was the most conserved one without any nucleotide variation in stem regions within Muscomorpha. Phylogenetic relationships among the major lineages of Muscomorpha were reconstructed using a complete set of mitochondrial genes. Bayesian and maximum likelihood analyses generated congruent topologies. Our results supported the monophyly of five species within the Syrphidae (Syrphoidea). The Platypezoidea was sister to all other species of Muscomorpha in our phylogeny. Our study demonstrated the power of the complete mitochondrial gene set for phylogenetic analysis in Muscomorpha.
Ligusticum L., one of the largest members in Apiaceae, encompasses medicinally important plants, the taxonomic statuses of which have been proved to be difficult to resolve. In the current study, the complete chloroplast genomes of seven crucial plants of the best-known herbs in Ligusticum were presented. The seven genomes ranged from 148,275 to 148,564 bp in length with a highly conserved gene content, gene order and genomic arrangement. A shared dramatic decrease in genome size resulted from a lineage-specific inverted repeat (IR) contraction, which could potentially be a promising diagnostic character for taxonomic investigation of Ligusticum, was discovered, without affecting the synonymous rate. Although a higher variability was uncovered in hotspot divergence regions that were unevenly distributed across the chloroplast genome, a concatenated strategy for rapid species identification was proposed because separate fragments inadequately provided variation for fine resolution. Phylogenetic inference using plastid genome-scale data produced a concordant topology receiving a robust support value, which revealed that L. chuanxiong had a closer relationship with L. jeholense than L. sinense, and L. sinense cv. Fuxiong had a closer relationship to L. sinense than L. chuanxiong, for the first time. Our results not only furnish concrete evidence for clarifying Ligusticum taxonomy but also provide a solid foundation for further pharmaphylogenetic investigation.
Chloroplast genome sequences are very useful for species identification and phylogenetics. Chuanminshen (Chuanminshen violaceum Sheh et Shan) is an important traditional Chinese medicinal plant, for which the phylogenetic position is still controversial. In this study, the complete chloroplast genome of Chuanminshen violaceum Sheh et Shan was determined. The total size of Chuanminshen chloroplast genome was 154,529 bp with 37.8% GC content. It has the typical quadripartite structure, a large single copy (17,800 bp) and a small single copy (84,171 bp) and a pair of inverted repeats (26,279 bp). The whole genome harbors 132 genes, which includes 85 protein coding genes, 37 tRNA genes, eight rRNA genes, and two pseudogenes. Thirty-nine SSR loci, 32 tandem repeats and 49 dispersed repeats were found. Phylogenetic analyses results with the help of MEGA showed a new insight for the Chuanminshen phylogenetic relationship with the reported chloroplast genomes in Apiales plants.
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