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To understand the evolutionary processes leading to the diversity of Asian colobines, we report here on a phylogenetic, phylogeographical and population genetic analysis of three closely related langurs, Trachypithecus francoisi, T. poliocephalus and T. leucocephalus, which are all characterized by different pelage coloration predominantly on the head and shoulders. Therefore, we sequenced a 395 bp long fragment of the mitochondrial control region from 178 T. francoisi, 54 T. leucocephalus and 19 T. poliocephalus individuals, representing all extant populations of these three species. We found 29 haplotypes in T. francoisi, 12 haplotypes in T. leucocephalus and three haplotypes in T. poliocephalus. T. leucocephalus and T. poliocephalus form monophyletic clades, which are both nested within T. francoisi, and diverged from T. francoisi recently, 0.46-0.27 (T. leucocephalus) and 0.50-0.25 million years ago (T. poliocephalus). Thus, T. francoisi appears as a polyphyletic group, while T. leucocephalus and T. poliocephalus are most likely independent descendents of T. francoisi that are both physically separated from T. francoisi populations by rivers, open sea or larger habitat gaps. Since T. francoisi populations show no variability in pelage coloration, pelage coloration in T. leucocephalus and T. poliocephalus is most likely the result of new genetic mutations after the split from T. francoisi and not of the fixation of different characters derived from an ancestral polymorphism. This case study highlights that morphological changes for example in pelage coloration can occur in isolated populations in relatively short time periods and it provides a solid basis for studies in related species. Nevertheless, to fully understand the evolutionary history of these three langur species, nuclear loci should be investigated as well.

The metabolism of potato (Solanum tuberosum) roots constitutively over- and underexpressing hexokinase (HK, EC 2.7.1.1) was examined. An 11-fold variation in HK activity resulted in altered root growth, with antisense roots growing better than sense roots. Quantification of sugars, organic acids and amino acids in transgenic roots demonstrated that the manipulation of HK activity had very little effect on the intracellular pools of these metabolites. However, adenylate and free Pi levels were negatively affected by an increase in HK activity. The flux control coefficient of HK over the phosphorylation of glucose was measured for the first time in plants. Its value varied with HK level. It reached 1.71 at or below normal HK activity value and was much lower (0.32) at very high HK levels. Measurements of glycolytic flux and O(2) uptake rates demonstrated that the differences in glucose phosphorylation did not affect significantly glycolytic and respiratory metabolism. We hypothesized that these results could be explained by the existence of a futile cycle between the pools of hexose-Ps and carbohydrates. This view is supported by several lines of evidence. Firstly, activities of enzymes capable of catalyzing these reactions were detected in roots, including a hexose-P phosphatase. Secondly, metabolic tracer experiments using (14)C-glucose as precursor showed the formation of (14)C-fructose and (14)C-sucrose. We conclude that futile cycling of hexose-P could be partially responsible for the differences in energetic status in roots with high and low HK activity and possibly cause the observed alterations in growth in transgenic roots. The involvement of HK and futile cycles in the control of glucose-6P metabolism is discussed.

Insects are the most diverse group of animals on the planet, comprising over 90% of all metazoan life forms, and have adapted to a wide diversity of ecosystems in nearly all environments. They have evolved highly sensitive chemical senses that are central to their interaction with their environment and to communication between individuals. Understanding the molecular bases of insect olfaction is therefore of great importance from both a basic and applied perspective. Odorant binding proteins (OBPs) are some of most abundant proteins found in insect olfactory organs, where they are the first component of the olfactory transduction cascade, carrying odorant molecules to the olfactory receptors. We carried out a search for OBPs in the genome of the parasitoid wasp Nasonia vitripennis and identified 90 sequences encoding putative OBPs. This is the largest OBP family so far reported in insects. We report unique features of the N. vitripennis OBPs, including the presence and evolutionary origin of a new subfamily of double-domain OBPs (consisting of two concatenated OBP domains), the loss of conserved cysteine residues and the expression of pseudogenes. This study also demonstrates the extremely dynamic evolution of the insect OBP family: (i) the number of different OBPs can vary greatly between species; (ii) the sequences are highly diverse, sometimes as a result of positive selection pressure with even the canonical cysteines being lost; (iii) new lineage specific domain arrangements can arise, such as the double domain OBP subfamily of wasps and mosquitoes. [ABSTRACT FROM AUTHOR]

Insect chemosensory proteins (CSPs) have been proposed to capture and transport hydrophobic chemicals from air to olfactory receptors in the lymph of antennal chemosensilla. They may represent a new class of soluble carrier protein involved in insect chemoreception. However, their specific functional roles in insect chemoreception have not been fully elucidated. In this study, we report for the first time three novel CSP genes (AlinCSP1-3) of the alfalfa plant bug Adelphocoris lineolatus (Goeze) by screening the antennal cDNA library. The qRT-PCR examinations of the transcript levels revealed that all three genes (AlinCSP1-3) are mainly expressed in the antennae. Interestingly, these CSP genes AlinCSP1-3 are also highly expressed in the 5th instar nymphs, suggesting a proposed function of these CSP proteins (AlinCSP1-3) in the olfactory reception and in maintaining particular life activities into the adult stage. Using bacterial expression system, the three CSP proteins were expressed and purified. For the first time we characterized the types of sensilla in the antennae of the plant bug using scanning electron microscopy (SEM). Immunocytochemistry analysis indicated that the CSP proteins were expressed in the pheromone-sensitive sensilla trichodea and general odorant-sensitive sensilla basiconica, providing further evidence of their involvement in chemoreception. The antennal activity of 55 host-related semiochemicals and sex pheromone compounds in the host location and mate selection behavior of A. lineolatus was investigated using electroantennogram (EAG), and the binding affinities of these chemicals to the three CSPs (AlinCSP1-3) were measured using fluorescent binding assays. The results showed several host-related semiochemicals, (Z)-3-hexen-1-ol, (E)-2-hexen-1-al and valeraldehyde, have a high binding affinity with AlinCSP1-3 and can elicit significant high EAG responses of A. lineolatus antennae. Our studies indicate the three antennae- biased CSPs may mediate host recognition in the alfalfa plant bug A. lineolatus. [ABSTRACT FROM AUTHOR]

The Mediterranean fruit fly, Ceratitis capitata (medfly), is an extremely invasive agricultural pest due to its extremely wide host range and its ability to adapt to a broad range of climatic conditions and habitats. Chemosensory behaviour plays an important role in many crucial stages in the life of this insect, such as the detection of pheromone cues during mate pursuit and odorants during host plant localisation. Thus, the analysis of the chemosensory gene repertoire is an important step for the interpretation of the biology of this species and consequently its invasive potential. Moreover, these genes may represent ideal targets for the development of novel, effective control methods and pest population monitoring systems. Expressed sequence tag libraries from C. capitata adult heads, embryos, male accessory glands and testes were screened for sequences encoding putative odorant binding proteins (OBPs). A total of seventeen putative OBP transcripts were identified, corresponding to 13 Classic, three Minus-C and one Plus-C subfamily OBPs. The tissue distributions of the OBP transcripts were assessed by RT-PCR and a subset of five genes with predicted proteins sharing high sequence similarities and close phylogenetic affinities to Drosophila melanogaster pheromone binding protein related proteins (PBPRPs) were characterised in greater detail. Real Time quantitative PCR was used to assess the effects of maturation, mating and time of day on the transcript abundances of the putative PBPRP genes in the principal olfactory organs, the antennae, in males and females. The results of the present study have facilitated the annotation of OBP genes in the recently released medfly genome sequence and represent a significant contribution to the characterisation of the medfly chemosensory repertoire. The identification of these medfly OBPs/PBPRPs permitted evolutionary and functional comparisons with homologous sequences from other tephritids of the genera Bactrocera and Rhagoletis.

Insects use their sensitive and selective olfactory system to detect outside chemical odorants, such as female sex pheromones and host plant volatiles. Several groups of olfactory proteins participate in the odorant detection process, including odorant binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs), ionotropic receptors (IRs) and sensory neuron membrane proteins (SNMPs). The identification and functional characterization of these olfactory proteins will enhance our knowledge of the molecular basis of insect chemoreception. In this study, we report the identification and differential expression profiles of these olfactory genes in the black cutworm moth Agrotis ipsilon. In total, 33 OBPs, 12 CSPs, 42 ORs, 24 IRs, 2 SNMPs and 1 gustatory receptor (GR) were annotated from the A. ipsilon antennal transcriptomes, and further RT-PCR and RT-qPCR revealed that 22 OBPs, 3 CSPs, 35 ORs, 14 IRs and the 2 SNMPs are uniquely or primarily expressed in the male and female antennae. Furthermore, one OBP (AipsOBP6) and one CSP (AipsCSP2) were exclusively expressed in the female sex pheromone gland. These antennae-enriched OBPs, CSPs, ORs, IRs and SNMPs were suggested to be responsible for pheromone and general odorant detection and thus could be meaningful target genes for us to study their biological functions in vivo and in vitro.

Green leaf bug Apolygus lucorum (Meyer-Dür) is one of the major pests in agriculture. Management of A. lucorum was largely achieved by using pesticides. However, the increasing population of A. lucorum since growing Bt cotton widely and the increased awareness of ecoenvironment and agricultural product safety makes their population-control very challenging. Therefore this study was conducted to explore a novel ecological approach, synthetic plant volatile analogues, to manage the pest. Here, plant volatile analogues were first designed and synthesized by combining the bioactive components of β-ionone and benzaldehyde. The stabilities of β-ionone, benzaldehyde and analogue 3 g were tested. The electroantennogram (EAG) responses of A. lucorum adult antennae to the analogues were recorded. And the behavior assay and filed experiment were also conducted. In this study, thirteen analogues were acquired. The analogue 3 g was demonstrated to be more stable than β-ionone and benzaldehyde in the environment. Many of the analogues elicited EAG responses, and the EAG response values to 3 g remained unchanged during seven-day period. 3 g was also demonstrated to be attractive to A. lucorum adults in the laboratory behavior experiment and in the field. Its attractiveness persisted longer than β-ionone and benzaldehyde. This indicated that 3 g can strengthen attractiveness to insect and has potential as an attractant. Our results suggest that synthetic plant volatile analogues can strengthen attractiveness to insect. This is the first published study about synthetic plant volatile analogues that have the potential to be used in pest control. Our results will support a new ecological approach to pest control and it will be helpful to ecoenvironment and agricultural product safety.

Insects interact with their environment and respond to the changes in host plant conditions using semiochemicals. Such ecological interactions are facilitated by the olfactory sensilla and the use of olfactory recognition proteins. The cotton aphid Aphis gossypii can change its phenotype in response to ecological conditions. They reproduce mainly as wingless asexual morphs but develop wings to find mates or new plant hosts under the influence of environmental factors such as temperature, plant nutrition and population density. Two groups of small soluble proteins, odorant binding proteins (OBPs) and chemosensory proteins (CSPs) are believed to be involved in the initial biochemical recognition steps in semiochemical perception. However, the exact molecular roles that these proteins play in insect olfaction remain to be discovered. In this study, we compared the transcriptomes of three asexual developmental stages (wingless spring and summer morphs and winged adults) and characterised 9 OBP and 9 CSP genes. The gene structure analysis showed that the number and length of introns in these genes are much higher and this appears to be unique feature of aphid OBP and CSP genes in general. Another unique feature in aphids is a higher abundance of CSP transcripts than OBP transcripts, suggesting an important role of CSPs in aphid physiology and ecology. We showed that some of the transcripts are overexpressed in the antennae in comparison to the bodies and highly expressed in the winged aphids compared to wingless morphs, suggesting a role in host location. We examined the differential expression of these olfactory genes in ten aphid species and compared the expression profile with the RNA-seq analyses of 25 pea aphid transcriptome libraries hosted on AphidBase.

BACKGROUND: A large number of insect chemosensory genes from different gene subfamilies have been identified and annotated, but their functional diversity and complexity are largely unknown. A systemic examination of expression patterns in chemosensory organs could provide important information. METHODOLOGY/PRINCIPAL FINDINGS: We identified 92 putative chemosensory genes by analysing the transcriptome of the antennae and female sex pheromone gland of the purple stem borer Sesamia inferens, among them 87 are novel in this species, including 24 transcripts encoding for odorant binding proteins (OBPs), 24 for chemosensory proteins (CSPs), 2 for sensory neuron membrane proteins (SNMPs), 39 for odorant receptors (ORs) and 3 for ionotropic receptors (IRs). The transcriptome analyses were validated and quantified with a detailed global expression profiling by Reverse Transcription-PCR for all 92 transcripts and by Quantitative Real Time RT-PCR for selected 16 ones. Among the chemosensory gene subfamilies, CSP transcripts are most widely and evenly expressed in different tissues and stages, OBP transcripts showed a clear antenna bias and most of OR transcripts are only detected in adult antennae. Our results also revealed that some OR transcripts, such as the transcripts of SNMP2 and 2 IRs were expressed in non-chemosensory tissues, and some CSP transcripts were antenna-biased expression. Furthermore, no chemosensory transcript is specific to female sex pheromone gland and very few are found in the heads. CONCLUSION: Our study revealed that there are a large number of chemosensory genes expressed in S. inferens, and some of them displayed unusual expression profile in non-chemosensory tissues. The identification of a large set of putative chemosensory genes of each subfamily from a single insect species, together with their different expression profiles provide further information in understanding the functions of these chemosensory genes in S. inferens as well as other insects.

Insects are the most diverse group of animals on the planet, comprising over 90% of all metazoan life forms, and have adapted to a wide diversity of ecosystems in nearly all environments. They have evolved highly sensitive chemical senses that are central to their interaction with their environment and to communication between individuals. Understanding the molecular bases of insect olfaction is therefore of great importance from both a basic and applied perspective. Odorant binding proteins (OBPs) are some of most abundant proteins found in insect olfactory organs, where they are the first component of the olfactory transduction cascade, carrying odorant molecules to the olfactory receptors. We carried out a search for OBPs in the genome of the parasitoid wasp Nasonia vitripennis and identified 90 sequences encoding putative OBPs. This is the largest OBP family so far reported in insects. We report unique features of the N. vitripennis OBPs, including the presence and evolutionary origin of a new subfamily of double-domain OBPs (consisting of two concatenated OBP domains), the loss of conserved cysteine residues and the expression of pseudogenes. This study also demonstrates the extremely dynamic evolution of the insect OBP family: (i) the number of different OBPs can vary greatly between species; (ii) the sequences are highly diverse, sometimes as a result of positive selection pressure with even the canonical cysteines being lost; (iii) new lineage specific domain arrangements can arise, such as the double domain OBP subfamily of wasps and mosquitoes.