- Hybrid genome assembly of a neotropical mutualistic ant. [Journal Article]
- GBGenome Biol Evol 2019 Jul 22
- The success of social insects is largely intertwined with their highly advanced chemical communication system that facilitates recognition and discrimination of species and nest-mates, recruitment, a…
The success of social insects is largely intertwined with their highly advanced chemical communication system that facilitates recognition and discrimination of species and nest-mates, recruitment, and division of labour. Hydrocarbons, which cover the cuticle of insects, not only serve as waterproofing agents but also constitute a major component of this communication system. Two cryptic Crematogaster species, which share their nest with Camponotus ants, show striking diversity in their cuticular hydrocarbon (CHC) profile. This mutualistic system therefore offers a great opportunity to study the genetic basis of CHC divergence between sister species. As a basis for further genome-wide studies high-quality genomes are needed. Here we present the annotated draft genome for Crematogaster levior A. By combining the three most commonly used sequencing techniques - Illumina, PacBio and Oxford Nanopore - we constructed a high-quality de novo ant genome. We show that even low coverage of long reads can add significantly to overall genome contiguity. Annotation of desaturase and elongase genes, which play a role in CHC biosynthesis revealed one of the largest repertoires in ants and a higher number of desaturases in general than in other Hymenoptera. This may provide a mechanistic explanation for the high diversity observed in C. levior CHC profiles.
- Susceptibility and alterations by diflubenzuron in larvae of Aedes aegypti. [Journal Article]
- AIArch Insect Biochem Physiol 2019 Jul 22; :e21604
- Benzoylphenyl ureas inhibit chitin synthesis and interfere with the molting process in arthropods. In this study, the effect of diflubenzuron on third-instar larvae of Aedes aegypti was evaluated. Th…
Benzoylphenyl ureas inhibit chitin synthesis and interfere with the molting process in arthropods. In this study, the effect of diflubenzuron on third-instar larvae of Aedes aegypti was evaluated. The susceptibility to the product was determined, and the alterations generated were shown through light and electron microscopy. LC50 and LC90 were 0.23 and 0.47 ppm, respectively. The main alterations observed were the incapacity to complete the molt, a reduction of mobility, the fragmentation of the old cuticle, a division of the body segments that was not evident, and the deformation of the caudal structures. Images of the ultrastructure are included, where breaking zones in the cuticle were observed, separation of the cuticle, the epidermis and the muscles, and these latter with a disorganized arrangement. In low concentrations, from 0.15 ppm, diflubenzuron causes alterations in the behavior and morphology of Ae. aegypti.
- Characterization of multicopper oxidase genes in the green rice leafhopper, Nephotettix cincticeps (Hemiptera: Cicadellidae), with focus on salivary gland-specific genes. [Journal Article]
- AIArch Insect Biochem Physiol 2019 Jul 22; :e21602
- Multicopper oxidase (MCO) enzymes are present ubiquitously and act on diverse substrates. Recently, the presence of multiple MCO genes has been described in many insects. Based on sialotranscriptome …
Multicopper oxidase (MCO) enzymes are present ubiquitously and act on diverse substrates. Recently, the presence of multiple MCO genes has been described in many insects. Based on sialotranscriptome data, we identified and comprehensively characterized six MCO genes: NcLac1S, 1G, and 2-5 in the green rice leafhopper, Nephotettix cincticeps (Hemiptera: Cicadellidae). NcLac1S and NcLac1G belong to the MCO1 ortholog of other insects. NcLac2 forms a clade with MCO2s involved in the sclerotization and pigmentation of the cuticle. NcLac3 and NcLac4 form a clade with NlMCO3 -5 of the hemipteran Nilaparvata luges. NcLac5 forms a clade with MCORPs (MCO-related proteins) that lack amino acid residues normally highly conserved in copper-coordinated MCOs. NcLac1S and NcLac3 were specifically expressed in the salivary glands; whereas NcLac5 was primarily expressed in the salivary glands. Only NcLac3 protein is considered to have laccase activity in the salivary glands and salivary sheaths ejected by the insect. NcLac1G expression was relatively high in the testis. NcLac2 and NcLac4 were specifically expressed in the integument and in Malpighian tubules, respectively. Knockdown by RNA interference (RNAi) of either NcLac2 and NcLac5 in nymphs caused high mortality. All NcLac2-knockdown nymphs showed depigmentation and soft cuticle, and eventually died, as did other MCO2-knockdown insects. DsNcLac5-injected nymphs (third, fourth, and fifth-instar) showed high mortality, but injection into adults had no effect on survival or number of eggs deposited, suggesting that NcLac5 is not essential for survival after molting (eclosion). NcLac5 could be a promising target gene for control of N. cincticeps.
- Cell death regulation but not abscisic acid signaling is required for the enhanced Botrytis immunity in cuticle permeable mutants. [Journal Article]
- JEJ Exp Bot 2019 Jul 22
- Prevailing evidence supports that ABA negatively influences immunity against the fungal pathogen, Botrytiscinerea (Botrytis), in most but not all cases. ABA is required for cuticle biosynthesis, and …
Prevailing evidence supports that ABA negatively influences immunity against the fungal pathogen, Botrytiscinerea (Botrytis), in most but not all cases. ABA is required for cuticle biosynthesis, and cuticle permeability enhances Botrytis immunity via unknown mechanisms. This complex web of responses obscures the role of ABA in Botrytis immunity. Here, we addressed the relationships between ABA sensitivity, cuticle permeability, and Botrytis immunity, with the Arabidopsis thaliana ABA hypersensitive mutants, protein phosphatase2c quadruple mutant (pp2c-q) and enhanced response to aba1 (era1-2). Neither pp2c-q nor era1-2 exhibited phenotypes predicted by the known roles of ABA; conversely, era1-2 was cuticle permeable and Botrytis-resistant. We employed RNA-seq analysis with cuticle permeable mutants of differing ABA sensitivities and identified a core set of constitutively activated genes involved in Botrytis immunity and susceptibility to biotrophs independent of ABA signaling. Further, botrytis susceptible1 (bos1), a mutant with deregulated cell death and enhanced ABA sensitivity, suppressed the Botrytis-immunity of cuticle permeable mutants and this effect was linearly correlated to the extent of the wound-induced cell-death spread in bos1. Overall, our data demonstrate that Botrytis immunity conferred by cuticle permeability can be genetically uncoupled from PP2C-regulated ABA-sensitivity, but required negative regulation of a parallel of ABA-dependent cell death pathway.
- The oral gland, a new exocrine organ of termites. [Journal Article]
- ASArthropod Struct Dev 2019 Jul 17; :100876
- Termites have a rich set of exocrine glands. These glands are located all over the body, appearing in the head, thorax, legs and abdomen. Here, we describe the oral gland, a new gland formed by no mo…
Termites have a rich set of exocrine glands. These glands are located all over the body, appearing in the head, thorax, legs and abdomen. Here, we describe the oral gland, a new gland formed by no more than a few tens of Class I secretory cells. The gland is divided into two secretory regions located just behind the mouth, on the dorsal and ventral side of the pharynx, respectively. The dominant secretory organelle is a smooth endoplasmic reticulum. Secretion release is under direct control of axons located within basal invaginations of the secretory cells. The secretion is released through a modified porous cuticle located at the mouth opening. We confirmed the presence of the oral gland in workers and soldiers of several wood- and soil-feeding species of Rhinotermitidae and Termitidae, suggesting a broader distribution of the oral gland among termites. The oral gland is the smallest exocrine gland described in termites so far. We hypothesise that the oily secretion can either ease the passage of food or serve as a primer pheromone.
- Fine mapping of an up-curling leaf locus (BnUC1) in Brassica napus. [Journal Article]
- BPBMC Plant Biol 2019 Jul 19; 19(1):324
- CONCLUSIONS: An up-curling leaf mutant Bnuc1 was controlled by one dominant locus BnUC1. This locus had positive effects on photosynthetic efficiency, negative effects on some agronomic traits, and may help to increase planting density in B. napus.
- Adaptations of dragonfly larvae and their exuviae (Insecta: Odonata), attachment devices and their crucial role during emergence. [Journal Article]
- JIJ Insect Physiol 2019 Jul 16; :103914
- Moulting, especially in 'hemimetabolous' insects that emerge upside down, is a crucial moment in their live. Losing their attachment during this situation can be fatal for survival. We here studied t…
Moulting, especially in 'hemimetabolous' insects that emerge upside down, is a crucial moment in their live. Losing their attachment during this situation can be fatal for survival. We here studied the emergence of dragonfly adults, describe structures involved in larval attachment to the substrate, and biomechanically test the pull-off forces of exuviae to natural substrates. Confocal laser scanning microscopy and scanning electron microscopy were used to describe both morphology and material composition of the leg cuticle of Anax imperator larvae. The results show that the combination of morphological and behavioral adaptations provides reliable anchorage of exuviae to the substrates. We determined a safety factor of 14, and demonstrated that this staggered safety system experiencing several unlocking and relocking events withstand multiple disturbances before the entire exuvia is completely detaches. This furthers our understanding of interlocking and anchorage of insects in general and may allow for future applications.
- The F-box Protein SAGL1 and ECERIFERUM3 Regulate Cuticular Wax Biosynthesis in Response to Changes in Humidity in Arabidopsis. [Journal Article]
- PCPlant Cell 2019 Jul 18
- Cuticular waxes that cover the above-ground parts of land plants are essential for their survival in terrestrial environment. However, little is known about the regulatory mechanisms underlying cutic…
Cuticular waxes that cover the above-ground parts of land plants are essential for their survival in terrestrial environment. However, little is known about the regulatory mechanisms underlying cuticular wax biosynthesis in response to changes in ambient humidity. Here, we report that SMALL AND GLOSSY LEAVES 1 (SAGL1) Kelch repeat F-box protein mediates proteasome-dependent degradation of ECERIFERUM3 (CER3), a biosynthetic enzyme that is involved in the production of very long chain alkanes, which are the major wax components and thereby negatively regulates cuticular wax biosynthesis in Arabidopsis. Disruption of SAGL1 caused severe growth retardation, enhanced tolerance to drought and increased wax accumulation in stems, leaves, and roots. Cytoplasmic SAGL1 physically interacts with CER3 and targets CER3 for degradation. GUS expression was observed in roots of pSAGL1::GUS plants, but barely detected in their aerial organs. High humidity-induced levels of GUS activity and SAGL1 transcripts were reduced by ABA treatment and water-deficit. SAGL1 protein levels also increased under high humidity and its stability is regulated by the 26S proteasome. This study revealed that the SAGL1-CER3 module negatively regulates Arabidopsis cuticular wax biosynthesis in response to changes to humidity conditions and suggested the importance of permeable cuticle formation in terrestrial plants under high humidity.
- RNA-seq Analysis of Clitea metallica (Coleoptera: Chrysomelidae), Provides Insights Into Cuticle-Related Genes and miRNAs. [Journal Article]
- JEJ Econ Entomol 2019 Jul 18
- The citrus leaf beetle, Clitea metallica, is a specialized citrus pest through feeding on fresh leaves by larva and adults, and causes nicks and holes into leaves, leaving only a waxy surface layer. …
The citrus leaf beetle, Clitea metallica, is a specialized citrus pest through feeding on fresh leaves by larva and adults, and causes nicks and holes into leaves, leaving only a waxy surface layer. Insect cuticle is a complex exoskeleton that is not only involved in development but also protects the insect from environmental contaminations. Due to these key roles of the cuticle, cuticle-related genes are currently investigated in understanding the insect physiology in adaptation. Therefore, in this study, we built two libraries, transcriptomic (43 million clean reads) and small RNA (17 million clean reads), of C. metallica to identify cuticle-related genes and possibly associated miRNAs, being as an example to explore these data sets. Our results showed that a total of 47 cuticular protein genes were identified and most of these genes harbored a conserved motif (the Rebers and Riddiford motif) and belonged to the CPR family. Unigenes encoding proteins involved in chitin synthesis and degradation were also identified, including chitin synthase (2 unigenes), chitinase (14 unigenes), chitinase-like protein (2 unigenes), and chitin deacetylase (5 unigenes). Based on the small RNA library, we identified 30 miRNAs conserved across insect species. Among these miRNAs, 14 were predicted to be target genes associated with cuticle synthesis and degradation. In summary, 70 cuticle-related genes and 14 cuticle-related miRNAs were identified based on the transcriptome and small RNA library of C. metallica. These data sets will promote the understanding of cuticle molecular regulation in C. metallica as well as provide new potential targets for pest control.
New Search Next
- Identification and temporal expression profiles of cuticular proteins in the endoparasitoid wasp, Microplitis mediator. [Journal Article]
- ISInsect Sci 2019 Jul 18
- Recently, parasitoid wasp species Microplitis mediator was evoke increasing research attention due to its possible use in the control of Lepidoptera insects. Because insect development involves chang…
Recently, parasitoid wasp species Microplitis mediator was evoke increasing research attention due to its possible use in the control of Lepidoptera insects. Because insect development involves changes in cuticle composition, identification and expression analysis of M. mediator cuticular proteins may clarify the mechanisms involved in parasite development processes. We found 70 cuticular proteins from the M. mediator transcriptome and divided them into seven distinct families. Expression profiling indicated that most of these cuticular protein genes have expression peaks specific for one particular developmental stage of M. mediator. Eggs and pupae have the highest number of transcriptionally active cuticular protein genes (47 and 52 respectively). Only 12 of these genes maintained high expression activity during late larval development. Functional analysis of two larval proteins, MmCPR3 and MmCPR14, suggested their important role in the proper organization of the cuticle layers of larvae. During M. mediator larval development, normal cuticle formation can be supported by a limited number of cuticular proteins. This article is protected by copyright. All rights reserved.