scholarly journals Identification and Expression Profiling of Peripheral Olfactory Genes in the Parasitoid Wasp Aphidius ervi (Hymenoptera: Braconidae) Reared on Different Aphid Hosts

Insects ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 397
Author(s):  
Gabriel I. Ballesteros ◽  
Daniela A. Sepúlveda ◽  
Christian C. Figueroa

Generalist parasitoids of aphids, such as the wasp Aphidius ervi, display significant differences in terms of host preference and host acceptance, depending on the host on which they developed (natal host), which is preferred over a non-natal host, a trait known as host fidelity. This trait allows females to quickly find hosts in heterogeneous environments, a process mediated by chemosensory/olfactory mechanisms, as parasitoids rely on olfaction and chemical cues during host selection. Thus, it is expected that proteins participating in chemosensory recognition, such as odorant-binding proteins (OBPs) and odorant receptors (ORs) would play a key role in host preference. In this study, we addressed the effect of parasitoid reciprocal host switching between two aphid hosts (Sitobion avenae and Acyrthosiphon pisum) on the expression patterns of chemosensory genes in the wasp A. ervi. First, by using a transcriptomic approach based on RNAseq of A. ervi females reared on S. avenae and A. pisum, we were able to annotate a total of 91 transcripts related to chemoperception. We also performed an in-silico expression analysis and found three OBPs and five ORs displaying different expression levels. Then, by using qRT-PCR amplification, we found significant differences in the expression levels of these eight genes when the parasitoids were reciprocally transplanted from S. avenae onto A. pisum and vice versa. This suggests that the expression levels of genes coding for odorant receptors and odorant-binding proteins would be regulated by the specific plant–aphid host complex where the parasitoids develop (maternal previous experience) and that chemosensory genes coding for olfactory mechanisms would play a crucial role on host preference and host acceptance, ultimately leading to the establishment of host fidelity in A. ervi parasitoids.

Author(s):  
Yu Pan ◽  
Xinxin Zhang ◽  
Zhun Wang ◽  
Lizhong Qi ◽  
Xinsheng Zhang ◽  
...  

Abstract The rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), is a destructive pest that causes damage to rice crops worldwide. The olfactory system is critical for host or mate location by weevils, but only limited information about the molecular mechanism of olfaction-related behaviour has been reported in this insect. In this study, we conducted SMRT-seq transcriptome analysis and obtained 54,378 transcripts, 38,706 of which were annotated. Based on these annotations, we identified 40 candidate chemosensory genes, including 31 odorant-binding proteins (OBPs), six chemosensory proteins (CSPs) and three sensory neuron membrane proteins (SNMPs). Phylogenetic analysis showed that LoryOBPs, LoryCSPs and LorySNMPs were distributed in various clades. The results of tissue expression patterns indicated that LoryOBPs were highly abundant in the antennae, whereas LoryCSPs were highly abundant not only in the antennae but also in the abdomen, head and wings. Our findings substantially expand the gene database of L. oryzophilus and may serve as a basis for identifying novel targets to disrupt key olfactory genes, potentially providing an eco-friendly strategy to control this pest in the future.


BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Hao Yuan ◽  
Huihui Chang ◽  
Lina Zhao ◽  
Chao Yang ◽  
Yuan Huang

Abstract Background The sophisticated insect olfactory system plays an important role in recognizing external odors and enabling insects to adapt to environment. Foraging, host seeking, mating, ovipositing and other forms of chemical communication are based on olfaction, which requires the participation of multiple olfactory genes. The exclusive evolutionary trend of the olfactory system in Orthoptera insects is an excellent model for studying olfactory evolution, but limited olfaction research is available for these species. The olfactory-related genes of Ceracris nigricornis Walker (Orthoptera: Acrididae), a severe pest of bamboos, have not yet been reported. Results We sequenced and analyzed the transcriptomes from different tissues of C. nigricornis and obtained 223.76 Gb clean data that were assembled into 43,603 unigenes with an N50 length of 2235 bp. Among the transcripts, 66.79% of unigenes were annotated. Based on annotation and tBLASTn results, 112 candidate olfactory-related genes were identified for the first time, including 20 odorant-binding proteins (OBPs), 10 chemosensory-binding proteins (CSPs), 71 odorant receptors (ORs), eight ionotropic receptors (IRs) and three sensory neuron membrane proteins (SNMPs). The fragments per kilobase per million mapped fragments (FPKM) values showed that most olfactory-related differentially expressed genes (DEGs) were enriched in the antennae, and these results were confirmed by detecting the expression of olfactory-related genes with quantitative real-time PCR (qRT-PCR). Among these antennae-enriched genes, some were sex-biased, indicating their different roles in the olfactory system of C. nigricornis. Conclusions This study provides the first comprehensive list and expression profiles of olfactory-related genes in C. nigricornis and a foundation for functional studies of these olfactory-related genes at the molecular level.


2021 ◽  
Author(s):  
Bhavika Mam ◽  
Snehal Karpe ◽  
Ramanathan Sowdhamini

AbstractOdorant binding proteins (OBPs) in insects bind to volatile chemical cue and help in their binding to odorant receptors. The odor coding hypothesis states that OBPs may bind with specificity to certain volatiles and aid the insect in various behaviours. Honeybees are eusocial insects with complex behaviour that requires olfactory inputs. Here, we have identified and annotated odorant binding proteins from the genome of the dwarf honey bee, Apis florea using an exhaustive homology-based bioinformatic pipeline and analyzed the evolutionary relationships between the OBP subfamilies. Our study suggests that Minus-C subfamily may have diverged from the Classic subfamily of odorant binding proteins in insects.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chao Ma ◽  
Chenchen Zhao ◽  
Shaowei Cui ◽  
Yan Zhang ◽  
Guangmei Chen ◽  
...  

Abstract Antennal olfaction plays a key role in insect survival, which mediates important behaviors like host search, mate choice, and oviposition site selection. As an oligophagous insect, olfaction is extremely important for Ophraella communa to locate host plants. However, information on the olfactory genes has been lacking in O. communa. Using next generation sequencing, we assembled the antennal transcriptome of O. communa and first reported the major chemosensory genes necessary for olfaction in this species. In this study, a total 105 candidate chemosensory genes were identified in O. communa antennae, including 25 odorant-binding proteins (OBPs), 11 chemosensory proteins (CSPs), four sensory neuron membrane proteins (SNMPs), 30 odorant receptors (ORs), 18 ionotropic receptors (IRs), and 17 gustatory receptors (GRs). We also identified full-length sequences of the highly conserved ORco and IR8a/25a family in O. communa. In addition, the expression profile of 15 ORs and four OBPs were validated by quantitative real-time polymerase chain reaction (qPCR). We found that OcomOR2/4/19 and OcomOBP19/20 had a biased expression in male antennae, and OcomOR8 had a biased expression in the female antennae. This large number of chemosensory genes handled by homology analysis and qPCR results will provide the first insights into molecular basis for the olfactory systems of O. communa as well as advance our understanding of olfactory mechanisms in Coleoptera.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Nikki K Larter ◽  
Jennifer S Sun ◽  
John R Carlson

Odorant binding proteins (Obps) are remarkable in their number, diversity, and abundance, yet their role in olfactory coding remains unclear. They are widely believed to be required for transporting hydrophobic odorants through an aqueous lymph to odorant receptors. We construct a map of the Drosophila antenna, in which the abundant Obps are mapped to olfactory sensilla with defined functions. The results lay a foundation for an incisive analysis of Obp function. The map identifies a sensillum type that contains a single abundant Obp, Obp28a. Surprisingly, deletion of the sole abundant Obp in these sensilla does not reduce the magnitude of their olfactory responses. The results suggest that this Obp is not required for odorant transport and that this sensillum does not require an abundant Obp. The results further suggest a novel role for this Obp in buffering changes in the odor environment, perhaps providing a molecular form of gain control.


Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 209
Author(s):  
Gabriele Rondoni ◽  
Alessandro Roman ◽  
Camille Meslin ◽  
Nicolas Montagné ◽  
Eric Conti ◽  
...  

In predatory ladybirds (Coleoptera: Coccinellidae), antennae are important for chemosensory reception used during food and mate location, and for finding a suitable oviposition habitat. Based on NextSeq 550 Illumina sequencing, we assembled the antennal transcriptome of mated Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) males and females and described the first chemosensory gene repertoire expressed in this species. We annotated candidate chemosensory sequences encoding 26 odorant receptors (including the coreceptor, Orco), 17 gustatory receptors, 27 ionotropic receptors, 31 odorant-binding proteins, 12 chemosensory proteins, and 4 sensory neuron membrane proteins. Maximum-likelihood phylogenetic analyses allowed to assign candidate H. axyridis chemosensory genes to previously described groups in each of these families. Differential expression analysis between males and females revealed low variability between sexes, possibly reflecting the known absence of relevant sexual dimorphism in the structure of the antennae and in the distribution and abundance of the sensilla. However, we revealed significant differences in expression of three chemosensory genes, namely two male-biased odorant-binding proteins and one male-biased odorant receptor, suggesting their possible involvement in pheromone detection. Our data pave the way for improving the understanding of the molecular basis of chemosensory reception in Coccinellidae.


Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 655 ◽  
Author(s):  
Zhang ◽  
Shen ◽  
Zhang ◽  
Wang ◽  
Kong ◽  
...  

Semanotus bifasciatus (Motschulsky) (Cerambycidae: Coleoptera) is a major forest borer in China, and attractants provide a promising method for the control of this pest. Exploration of the chemosensory mechanisms of S. bifasciatus is important for the development of efficient attractants for this pest. However, little information is available about the olfactory mechanisms of S. bifasciatus. Previous research has indicated that the trapping effects of the same attractant are different between Beijing and Shandong populations of S. bifasciatus. To explore the reasons for this, next-generation sequencing was performed to analyze the antennal transcriptome of both sexes of the two S. bifasciatus populations, and the olfactory-related genes were identified. Furthermore, the expression levels and single nucleotide polymorphisms (SNPs) of the olfactory-related genes between the two populations were compared. We found that the expression levels of odorant binding proteins (OBPs), odorant receptors (ORs), and sensory neuron membrane proteins (SNMPs) in male S. bifasciatus of the Beijing population were obviously lower than those in the Shandong population, and most of the conserved SNPs in OBPs and ORs of the two populations showed more diversity in the Beijing population. Our work provides a foundation for future research of the molecular olfactory mechanisms and pest management of S. bifasciatus, as well as other longhorn beetles.


2021 ◽  
Vol 9 ◽  
Author(s):  
Zheng-Quan Wang ◽  
Chun Wu ◽  
Gen-Ceng Li ◽  
Shu-Mei Nuo ◽  
Ning-Na Yin ◽  
...  

In Lepidoptera, RNA sequencing has become a useful tool in identifying chemosensory genes from antennal transcriptomes, but little attention is paid to non-antennal tissues. Though the antennae are primarily responsible for olfaction, studies have found that a certain number of chemosensory genes are exclusively or highly expressed in the non-antennal tissues, such as proboscises, legs and abdomens. In this study, we report a global transcriptome of 16 tissues from Dioryctria abietella, including chemosensory and non-chemosensory tissues. Through Illumina sequencing, totally 952,658,466 clean reads were generated, summing to 142.90 gigabases of data. Based on the transcriptome, 235 chemosensory-related genes were identified, comprising 42 odorant binding proteins (OBPs), 23 chemosensory proteins (CSPs), 75 odorant receptors (ORs), 62 gustatory receptors (GRs), 30 ionotropic receptors (IRs), and 3 sensory neuron membrane proteins (SNMPs). Compared to a previous study in this species, 140 novel genes were found. A transcriptome-wide analysis combined with PCR results revealed that except for GRs, the majority of other five chemosensory gene families in Lepidoptera were expressed in the antennae, including 160 chemosensory genes in D. abietella. Using phylogenetic and expression profiling analyses, members of the six chemosensory gene repertoires were characterized, in which 11 DabiORs were candidates for detecting female sex pheromones in D. abietella, and DabiOR23 may be involved in the sensing of plant-derived phenylacetaldehyde. Intriguingly, more than half of the genes were detected in the proboscises, and one fourth of the genes were found to have the expression in the legs. Our study not only greatly extends and improves the description of chemosensory genes in D. abietella, but also identifies potential molecular targets involved in olfaction, gustation and non-chemosensory functions for control of this pest.


2021 ◽  
Author(s):  
Gabriele Rondoni ◽  
Alessandro Roman ◽  
Camille Meslin ◽  
Nicolas Montagné ◽  
Eric Conti ◽  
...  

AbstractIn predatory ladybirds (Coleoptera: Coccinellidae), antennae are important for chemosensory reception used during food and mate location, and for finding a suitable oviposition habitat. Based on NextSeq 550 Illumina sequencing, we assembled the antennal transcriptome of mated Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) males and females and described the first chemosensory gene repertoire expressed in this species. We annotated candidate chemosensory sequences encoding 26 odorant receptors (including the coreceptor, Orco), 17 gustatory receptors, 27 ionotropic receptors, 31 odorant-binding proteins, 12 chemosensory proteins and 4 sensory neuron membrane proteins. Maximum-likelihood phylogenetic analyses allowed to assign candidate H. axyridis chemosensory genes to previously described groups in each of these families. Differential expression analysis between males and females revealed low variability between sexes, possibly reflecting the known absence of relevant sexual dimorphism in the structure of the antennae and in the distribution and abundance of the sensilla. However, we revealed significant differences in expression of three chemosensory genes, namely 2 male-biased odorant-binding proteins and 1 male-biased odorant receptor, suggesting their possible involvement in pheromone detection. Our data pave the way for improving the understanding of the molecular basis of chemosensory reception in Coccinellidae.SummaryThe predatory harlequin ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) has been widely released for classical and augmentative biological control programs of insect herbivores and is now distributed worldwide. Because of its invasive behavior and the threat it can pose to local biodiversity, this ladybird has been adopted as a model species for invasive biocontrol predators. A huge existing literature is available on this species. However, little is known about the mechanisms underlying H. axyridis smell and taste, even though these senses are important in this ladybird for courtship, mating and for locating suitable habitats for feeding and oviposition. Here we describe the first chemosensory gene repertoire that is expressed in the antennae of male and female H. axyridis. Our findings would likely represent the basis for future functional studies aiming at increasing the efficacy of H. axyridis in biological control or at reducing its populations in those areas where the ladybird has become a matter of concern due to its invasiveness.


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