The mitochondrial genome of Telenomus remus (Hymenoptera: Platygastridae).

Telenomus remus Nixon, 1937 is an important parasitoid of lepidopterans. We sequenced the mitochondrial genome of T. remus, 15,500 bp in size, and possessed all 37 typical mitochondrial genes. A few tRNAs show gene arrangements compared with the ancestral gene order, mainly involving in the four tRNA clusters (E-C-Y-Q-I-A, D-K, N-F-S1-R, and M-V). The nucleotide sequences of 13 protein-coding genes of this sequence and another seven species from Platygastridae were used for phylogenetic analysis by MrBayes, with two species from Cynipoidea as an outgroup. The topology demonstrated that T. remus was most closely related to Telenomus sp.

The first mitochondrial genome of the living-fossil sawfly Macroxyela ferruginea (Hymenoptera: Xyelidae, Macroxyelinae).

The living-fossil sawfly Macroxyela ferruginea (Xyelidae: Macroxyelinae) was one of the oldest species of Hymenoptera. We sequenced the mitochondrial genome, 15,465 bp in size. All 37 typical mitochondrial genes were possessed. There is only one rearrangement of gene order, where trnM and trnQ were shuffled. We also found this order was shared with Xyela sp., which also belongs to family Xyelidae. The 13 protein-coding genes of this sequence and the other 10 species from eight superfamilies in Hymenoptera were all used for phylogenetic analysis by maximum likelihood (ML) analysis and Bayesian inference (BI), with Ascaloptynx appendiculatus from Neuroptera as an outgroup. The topology demonstrated that M. ferruginea was sister to Xyela sp., supporting that they belong to one family Xyelidae.

The first two mitochondrial genomes of wood wasps (Hymenoptera: Symphyta): Novel gene rearrangements and higher-level phylogeny of the basal hymenopterans.

The Symphyta has long been recognized as a paraphyletic grade forming the base of the remaining Hymenopteran, and the superfamily relationships within Symphyta remain controversial. Here, the first two representative mitochondrial genomes from the superfamily Siricoidea and Xiphydrioidea (Hymenoptera: Symphyta) are obtained using next-generation sequencing. The complete mitochondrial genome of Xiphydria sp. is 16,482 bp long with an A + T content of 84.18% while the incomplete one of Tremex columba is 16,847 bp long and A + T content is 81.69%. All 37 typical mitochondrial genes are possessed in both species. The secondary structure of tRNAs and rRNAs for both species are successfully predicted. Compared with the ancestral organization, seven and five tRNA genes are rearranged in mitochondrial genomes of Tremex and Xiphydria, respectively, which are the most rearrangement events within Symphyta. The rearrangement patterns in Tremex and Xiphydria present in this study are all novel to the Symphyta. Phylogenetic relationships among the major lineages of Symphyta are reconstructed using mitochondrial genomes. Both maximum likelihood and Bayesian inference analyses highly support Symphyta is a paraphyletic grade, Xyeloidea + (Tenthredinoidea + (Pamphilioidea + (Xiphydrioidea + (Cephoidea + (Orussoidea + Apocrita))))).

Parasitic insect-derived miRNAs modulate host development.

Parasitic wasps produce several factors including venom, polydnaviruses (PDVs) and specialized wasp cells named teratocytes that benefit the survival of offspring by altering the physiology of hosts. However, the underlying molecular mechanisms for the alterations remain unclear. Here we find that the teratocytes of Cotesia vestalis, an endoparasitoid of the diamondback moth Plutella xylostella, and its associated bracovirus (CvBV) can produce miRNAs and deliver the products into the host via different ways. Certain miRNAs in the parasitized host are mainly produced by teratocytes, while the expression level of miRNAs encoded by CvBV can be 100-fold greater in parasitized hosts than non-parasitized ones. We further show that one teratocyte-produced miRNA (Cve-miR-281-3p) and one CvBV-produced miRNA (Cve-miR-novel22-5p-1) arrest host growth by modulating expression of the host ecdysone receptor (EcR). Altogether, our results show the first evidence of cross-species regulation by miRNAs in animal parasitism and their possible function in the alteration of host physiology during parasitism.

The first two mitochondrial genomes of the family Aphelinidae with novel gene orders and phylogenetic implications.

Chalcidoidea is one of the most diverse group in Hymenoptera by possessing striking mitochondrial gene arrangement. By using next generation sequencing method, the first two nearly complete mitochondrial genomes in the family Aphelinidae (Insecta, Hymenopetra, Chalcidoidea) were obtained in this study. Almost all previously sequenced mitochondrial genome of Chalcidoidea species have a large inversion including six genes (atp6-atp8-trnD-trnK-cox2-trnL2-cox1) as compared with ancestral mitochondrial genome, but these two Encarsia mitochondrial genomes had a large inversion including nine genes (nad3-trnG-atp6-atp8-trnD-trnK-cox2-trnL2-cox1), which was only congruent with the species in the genus Nasonia. Moreover, we found that one shuffling changes (trnD and trnK) happened in the species E. obtusiclava but not in another species E. formosa within the same genus, of which such shuffling within the same genus at this region was only detected in Polisters within Insecta. Phylogenetic analysis displayed that different data matrix (13PCG+ 2 rRNA or 13 PCG) and inference methods (BI or ML) indicate the identical topology with high nodal supports that Aphelinidae formed a sister group with (Trichogrammatidae + Aganoidae) and the monophyly of Pteramalidae. Our results also indicated the validity of assembling and feasibility of next-generation technology to obtain the mitochondrial genomes of parasitic Hymenoptera.

Gene arrangement and sequence of mitochondrial genomes yield insights into the phylogeny and evolution of bees and sphecid wasps (Hymenoptera: Apoidea).

The Apoidea represent a large and common superfamily of the Hymenoptera including the bees and sphecid wasps. A robust phylogenetic tree is essential to understanding the diversity, taxonomy and evolution of the Apoidea. In this study, features of apoid mitochondrial genomes were used to reconstruct phylogenetic relationships. Twelve apoid mitochondrial genomes were newly sequenced, representing six families and nine subfamilies. Gene rearrangement events have occurred in all apoid mitochondrial genomes sequenced to date. Sphecid wasps have both tRNA and protein-coding gene rearrangements in 5 of 8 species. In bees, the only rearranged genes are tRNAs; long-tongued bees (Apidae + Megachilidae) are characterized by movement of trnA to the trnI-trnQ-trnM tRNA cluster. Phylogenetic analyses of mitochondrial gene sequences support the known paraphyly of sphecid wasps, with bees nested within this clade. The Ampulicidae is sister to the remaining Apoidea. Crabronidae is paraphyletic, split into Crabronidae s.s. and Philanthidae, with the latter group a sister clade to bees. The monophyletic bees are either classified into two clades, long-tongued bees (Apidae + Megachilidae) and short-tongued bees (Andrenidae + Halictidae + Colletidae + Melitidae), or three groups with the Melitidae sister to the other bees. Our study showed that both gene sequences and arrangements provide information on the phylogeny of apoid families.

Next-Generation Sequencing of Two Mitochondrial Genomes from Family Pompilidae (Hymenoptera: Vespoidea) Reveal Novel Patterns of Gene Arrangement.

Animal mitochondrial genomes have provided large and diverse datasets for evolutionary studies. Here, the first two representative mitochondrial genomes from the family Pompilidae (Hymenoptera: Vespoidea) were determined using next-generation sequencing. The sequenced region of these two mitochondrial genomes from the species Auplopus sp. and Agenioideus sp. was 16,746 bp long with an A + T content of 83.12% and 16,596 bp long with an A + T content of 78.64%, respectively. In both species, all of the 37 typical mitochondrial genes were determined. The secondary structure of tRNA genes and rRNA genes were predicted and compared with those of other insects. Atypical trnS1 using abnormal anticodons TCT and lacking D-stem pairings was identified. There were 49 helices belonging to six domains in rrnL and 30 helices belonging to three domains in rrns present. Compared with the ancestral organization, four and two tRNA genes were rearranged in mitochondrial genomes of Auplopus and Agenioideus, respectively. In both species, trnM was shuffled upstream of the trnI-trnQ-trnM cluster, and trnA was translocated from the cluster trnA-trnR-trnN-trnS1-trnE-trnF to the region between nad1 and trnL1, which is novel to the Vespoidea. In Auplopus, the tRNA cluster trnW-trnC-trnY was shuffled to trnW-trnY-trnC. Phylogenetic analysis within Vespoidea revealed that Pompilidae and Mutillidae formed a sister lineage, and then sistered Formicidae. The genomes presented in this study have enriched the knowledge base of molecular markers, which is valuable in respect to studies about the gene rearrangement mechanism, genomic evolutionary processes and phylogeny of Hymenoptera.