Life Sciences Commons^™

20-Hydroxyecdysone (20e) Primary Response Gene E93 Modulates 20e Signaling To Promote Bombyx Larval-Pupal Metamorphosis, Xi Liu, Fangyin Dai, Enen Guo, Kang Li, Li Ma, Ling Tian, Yang Cao, Guozheng Zhang, Subba Reddy Palli, Sheng Li

Entomology Faculty Publications

As revealed in a previous microarray study to identify genes regulated by 20-hydroxyecdysone (20E) and juvenile hormone (JH) in the silkworm, Bombyx mori, E93 expression in the fat body was markedly low prior to the wandering stage but abundant during larval-pupal metamorphosis. Induced by 20E and suppressed by JH, E93 expression follows this developmental profile in multiple silkworm alleles. The reduction of E93 expression by RNAi disrupted 20E signaling and the 20E-induced autophagy, caspase activity, and cell dissociation in the fat body. Reducing E93 expression also decreased the expression of the 20E-induced pupal-specific cuticle protein genes and prevented growth …

Novel Mutations And Mutation Combinations Of Ryanodine Receptor In A Chlorantraniliprole Resistant Population Of Plutella Xylostella (L.), Lei Guo, Pei Liang, Xuguo Zhou, Xiwu Gao

Entomology Faculty Publications

A previous study documented a glycine to glutamic acid mutation (G4946E) in ryanodine receptor (RyR) was highly correlated to diamide insecticide resistance in field populations of Plutella xylostella (Lepidoptera: Plutellidae). In this study, a field population collected in Yunnan province, China, exhibited a 2128-fold resistance to chlorantraniliprole. Sequence comparison between resistant and susceptible P. xylostella revealed three novel mutations including a glutamic acid to valine substitution (E1338D), a glutamine to leucine substitution (Q4594L) and an isoleucine to methionine substitution (I4790M) in highly conserved regions of RyR. Frequency analysis of all four mutations in this field population showed that the three …

Cloning, Ligand-Binding, And Temporal Expression Of Ecdysteroid Receptors In The Diamondback Moth, Plutella Xylostella, Baozhen Tang, Wei Dong, Pei Liang, Xuguo Zhou, Xiwu Gao

Entomology Faculty Publications

BACKGROUND: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a devastating pest of cruciferous crops worldwide, and has developed resistance to a wide range of insecticides, including diacylhydrazine-based ecdysone agonists, a highly selective group of molt-accelerating biopesticides targeting the ecdysone receptors.

RESULT: In this study, we cloned and characterized the ecdysone receptors from P. xylostella, including the two isoforms of EcR and a USP. Sequence comparison and phylogenetic analysis showed striking conservations among insect ecdysone receptors, especially between P. xylostella and other lepidopterans. The binding affinity of ecdysteroids to in vitro-translated receptor proteins indicated that PxEcRB isoform bound specifically …

Comparative Mitogenomic Analysis Of Damsel Bugs Representing Three Tribes In The Family Nabidae (Insecta: Hemiptera), Hu Li, Haiyu Liu, Fan Song, Aimin Shi, Xuguo Zhou, Wanzhi Cai

Entomology Faculty Publications

BACKGROUND: Nabidae, a family of predatory heteropterans, includes two subfamilies and five tribes. We previously reported the complete mitogenome of Alloeorhynchus bakeri, a representative of the tribe Prostemmatini in the subfamily Prostemmatinae. To gain a better understanding of architecture and evolution of mitogenome in Nabidae, mitogenomes of five species representing two tribes (Gorpini and Nabini) in the subfamily Nabinae were sequenced, and a comparative mitogenomic analysis of three nabid tribes in two subfamilies was carried out.

METHODOLOGY/PRINCIPAL FINDINGS: Nabid mitogenomes share a similar nucleotide composition and base bias, except for the control region, where differences are observed at the …

Pyrosequencing The Bemisia Tabaci Transcriptome Reveals A Highly Diverse Bacterial Community And A Robust System For Insecticide Resistance, Wen Xie, Qing-Shu Meng, Qing-Jun Wu, Shao-Li Wang, Xin Yang, Ni-Na Yang, Ru-Mei Li, Xiao-Guo Jiao, Hui-Peng Pan, Bai-Ming Liu, Qi Su, Bao-Yun Xu, Song-Nian Hu, Xuguo Zhou, You-Jun Zhang

Entomology Faculty Publications

BACKGROUND: Bemisia tabaci (Gennadius) is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes.

METHODOLOGY AND PRINCIPAL FINDINGS: Using Roche 454 pyrosequencing, …

The Complete Mitochondrial Genome And Novel Gene Arrangement Of The Unique-Headed Bug Stenopirates Sp. (Hemiptera: Enicocephalidae), Hu Li, Hui Liu, Aimin Shi, Pavel Stys, Xuguo Zhou, Wanzhi Cai

Entomology Faculty Publications

Many of true bugs are important insect pests to cultivated crops and some are important vectors of human diseases, but few cladistic analyses have addressed relationships among the seven infraorders of Heteroptera. The Enicocephalomorpha and Nepomorpha are consider the basal groups of Heteroptera, but the basal-most lineage remains unresolved. Here we report the mitochondrial genome of the unique-headed bug Stenopirates sp., the first mitochondrial genome sequenced from Enicocephalomorpha. The Stenopirates sp. mitochondrial genome is a typical circular DNA molecule of 15, 384 bp in length, and contains 37 genes and a large non-coding fragment. The gene order differs substantially from …

Juvenile Hormone Regulates Vitellogenin Gene Expression Through Insulin-Like Peptide Signaling Pathway In The Red Flour Beetle, Tribolium Castaneum, Zhentao Sheng, Jingjing Xu, Hua Bai, Fang Zhu, Subba R. Palli

Entomology Faculty Publications

Our recent studies identified juvenile hormone (JH) and nutrition as the two key signals that regulate vitellogenin (Vg) gene expression in the red flour beetle, Tribolium castaneum. Juvenile hormone regulation of Vg synthesis has been known for a long time in several insects, but the mechanism of JH action is not known. Experiments were conducted to determine the mechanism of action of these two signals in regulation of Vg gene expression. Injection of bovine insulin or FOXO double-stranded RNA into the previtellogenic, starved, or JH-deficient female adults increased Vg mRNA and protein levels, thereby implicating the pivotal role for …

New Views On Strand Asymmetry In Insect Mitochondrial Genomes, Shu-Jun Wei, Min Shi, Xue-Xin Chen, Michael J. Sharkey, Cornelis Van Achterberg, Gong-Yin Ye, Jun-Hua He

Entomology Faculty Publications

Strand asymmetry in nucleotide composition is a remarkable feature of animal mitochondrial genomes. Understanding the mutation processes that shape strand asymmetry is essential for comprehensive knowledge of genome evolution, demographical population history and accurate phylogenetic inference. Previous studies found that the relative contributions of different substitution types to strand asymmetry are associated with replication alone or both replication and transcription. However, the relative contributions of replication and transcription to strand asymmetry remain unclear. Here we conducted a broad survey of strand asymmetry across 120 insect mitochondrial genomes, with special reference to the correlation between the signs of skew values and …

Comparative Mitogenomics Of Braconidae (Insecta: Hymenoptera) And The Phylogenetic Utility Of Mitochondrial Genomes With Special Reference To Holometabolous Insects, Shu-Jun Wei, Min Shi, Michael J. Sharkey, Cornelis Van Achterberg, Xue-Xin Chen

Entomology Faculty Publications

BACKGROUND: Animal mitochondrial genomes are potential models for molecular evolution and markers for phylogenetic and population studies. Previous research has shown interesting features in hymenopteran mitochondrial genomes. Here, we conducted a comparative study of mitochondrial genomes of the family Braconidae, one of the largest families of Hymenoptera, and assessed the utility of mitochondrial genomic data for phylogenetic inference at three different hierarchical levels, i.e., Braconidae, Hymenoptera, and Holometabola.

RESULTS: Seven mitochondrial genomes from seven subfamilies of Braconidae were sequenced. Three of the four sequenced A+T-rich regions are shown to be inverted. Furthermore, all species showed reversal of strand asymmetry, suggesting …

A Brain-Specific Cytochrome P450 Responsible For The Majority Of Deltamethrin Resistance In The Qtc279 Strain Of Tribolium Castaneum, Fang Zhu, R. Parthasarathy, Hua Bai, Katharina Woithe, Martin Kaussmann, Ralf Nauen, Douglas A. Harrison, Subba R. Palli

Entomology Faculty Publications

Cytochrome P450-mediated detoxification is one of the most important mechanisms involved in insecticide resistance. However, the molecular basis of this mechanism and the physiological functions of P450s associated with insecticide resistance remain largely unknown. Here, we exploited the functional genomics and reverse genetic approaches to identify and characterize a P450 gene responsible for the majority of deltamethrin resistance observed in the QTC279 strain of Tribolium castaneum. We used recently completed whole-genome sequence of T. castaneum to prepare custom microarrays and identified a P450 gene, CYP6BQ9, which showed more than a 200-fold higher expression in the deltamethrin-resistant QTC279 strain when compared …

Molecular Evidence For A Functional Ecdysone Signaling System In Brugia Malayi, George Tzertzinis, Ana L. Egaña, Subba Reddy Palli, Marc Robinson-Rechavi, Chris R. Gissendanner, Canhui Liu, Thomas R. Unnasch, Claude V. Maina

Entomology Faculty Publications

BACKGROUND: Filarial nematodes, including Brugia malayi, the causative agent of lymphatic filariasis, undergo molting in both arthropod and mammalian hosts to complete their life cycles. An understanding of how these parasites cross developmental checkpoints may reveal potential targets for intervention. Pharmacological evidence suggests that ecdysteroids play a role in parasitic nematode molting and fertility although their specific function remains unknown. In insects, ecdysone triggers molting through the activation of the ecdysone receptor: a heterodimer of EcR (ecdysone receptor) and USP (Ultraspiracle).

METHODS AND FINDINGS: We report the cloning and characterization of a B. malayi EcR homologue (Bma-EcR). Bma-EcR dimerizes with …

Co-Up-Regulation Of Three P450 Genes In Response To Permethrin Exposure In Permethrin Resistant House Flies, Musca Domestica, Fang Zhu, Ting Li, Lee Zhang, Nannan Liu

Entomology Faculty Publications

BACKGROUND: Insects may use various biochemical pathways to enable them to tolerate the lethal action of insecticides. For example, increased cytochrome P450 detoxification is known to play an important role in many insect species. Both constitutively increased expression (overexpression) and induction of P450s are thought to be responsible for increased levels of detoxification of insecticides. However, unlike constitutively overexpressed P450 genes, whose expression association with insecticide resistance has been extensively studied, the induction of P450s is less well characterized in insecticide resistance. The current study focuses on the characterization of individual P450 genes that are induced in response to permethrin …