Constitutive and insect‐induced transcriptomes of weevil‐resistant and susceptible Sitka spruce

Abstract Spruce weevil (Pissodes strobi) is a significant pest of regenerating spruce (Picea) and pine (Pinus) forests in North America. Weevil larvae feed in the bark, phloem, cambium, and outer xylem of apical shoots, causing stunted growth or mortality of young trees. We identified and characterized constitutive and weevil‐induced patterns of Sitka spruce (Picea sitchensis) transcriptomes in weevil‐resistant (R) and susceptible (S) trees using RNA sequencing (RNA‐seq) and differential expression (DE) analyses. We developed a statistical model for the analysis of RNA‐seq data from treatment experiments with a 2 × 3 factorial design to differentiate insect‐induced responses from the effects of mechanical damage. Across the different comparisons, we identified two major transcriptome contrasts: A large set of genes that was constitutively DE between R and S trees, and another set of genes that was DE in weevil‐induced S‐trees. The constitutive transcriptome unique to R trees appeared to be attuned to defense, while the constitutive transcriptome unique to S trees was enriched for growth‐related transcripts. Notably, a set of transcripts annotated as “fungal” was detected consistently in the transcriptomes. Fungal transcripts were identified as DE in the comparison of R and S trees and in the weevil‐affected DE transcriptome of S trees, suggesting a potential microbiome role in this conifer‐insect interaction

Disentangling detoxification: gene expression analysis of feeding mountain pine beetle illuminates molecular-level host chemical defense detoxification mechanisms.

The mountain pine beetle, Dendroctonus ponderosae, is a native species of bark beetle (Coleoptera: Curculionidae) that caused unprecedented damage to the pine forests of British Columbia and other parts of western North America and is currently expanding its range into the boreal forests of central and eastern Canada and the USA. We conducted a large-scale gene expression analysis (RNA-seq) of mountain pine beetle male and female adults either starved or fed in male-female pairs for 24 hours on lodgepole pine host tree tissues. Our aim was to uncover transcripts involved in coniferophagous mountain pine beetle detoxification systems during early host colonization. Transcripts of members from several gene families significantly increased in insects fed on host tissue including: cytochromes P450, glucosyl transferases and glutathione S-transferases, esterases, and one ABC transporter. Other significantly increasing transcripts with potential roles in detoxification of host defenses included alcohol dehydrogenases and a group of unexpected transcripts whose products may play an, as yet, undiscovered role in host colonization by mountain pine beetle

Antennal transcriptome analysis of the chemosensory gene families in the tree killing bark beetles, Ips typographus and Dendroctonus ponderosae (Coleoptera: Curculionidae: Scolytinae)

Background. The European spruce bark beetle, Ips typographus, and the North American mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae: Scolytinae), are severe pests of coniferous forests. Both bark beetle species utilize aggregation pheromones to coordinate mass-attacks on host trees, while odorants from host and non-host trees modulate the pheromone response. Thus, the bark beetle olfactory sense is of utmost importance for fitness. However, information on the genes underlying olfactory detection has been lacking in bark beetles and is limited in Coleoptera. We assembled antennal transcriptomes from next-generation sequencing of I. typographus and D. ponderosae to identify members of the major chemosensory multi-gene families. Results Gene ontology (GO) annotation indicated that the relative abundance of transcripts associated with specific GO terms was highly similar in the two species. Transcripts with terms related to olfactory function were found in both species. Focusing on the chemosensory gene families, we identified 15 putative odorant binding proteins (OBP), 6 chemosensory proteins (CSP), 3 sensory neuron membrane proteins (SNMP), 43 odorant receptors (OR), 6 gustatory receptors (GR), and 7 ionotropic receptors (IR) in I. typographus; and 31 putative OBPs, 11 CSPs, 3 SNMPs, 49 ORs, 2 GRs, and 15 IRs in D. ponderosae. Predicted protein sequences were compared with counterparts in the flour beetle, Tribolium castaneum, the cerambycid beetle, Megacyllene caryae, and the fruit fly, Drosophila melanogaster. The most notable result was found among the ORs, for which large bark beetle-specific expansions were found. However, some clades contained receptors from all four beetle species, indicating a degree of conservation among some coleopteran OR lineages. Putative GRs for carbon dioxide and orthologues for the conserved antennal IRs were included in the identified receptor sets. Conclusions The protein families important for chemoreception have now been identified in three coleopteran species (four species for the ORs). Thus, this study allows for improved evolutionary analyses of coleopteran olfaction. Identification of these proteins in two of the most destructive forest pests, sharing many semiochemicals, is especially important as they might represent novel targets for population control.Non UBCForestry, Faculty ofForest and Conservation Sciences, Department ofReviewedFacult

Mountain pine beetle host colonization transcriptomics

<p>Contains two XLXS files of transcriptomic data entitled:</p> <p>"Quantitative differences in gene transcript levels between <em>Dendroctonus ponderosae</em> starved females and those that have been fed in lodgepole pine for 24 hours"</p> <p>and</p> <p>"Quantitative differences in gene transcript levels between <em>Dendroctonus ponderosae</em> starved males and those that have been fed in lodgepole pine for 24 hours"</p> <p><em>Project title –</em> "Disentangling detoxification: Gene expression analysis of mountain pine beetle adults feeding on lodgepole pine illuminates molecular-level host chemical defense detoxification mechanisms."</p> <p>The article associated with the generation and analysis of this data is available at PLOS ONE:</p> <p>http://www.plosone.org/article/metrics/info%3Adoi%2F10.1371%2Fjournal.pone.0077777</p

The genome of the forest insect pest <i>Pissodes strobi</i> reveals genome expansion and evidence of a <i>Wolbachia</i> endosymbiont

AbstractThe highly diverse insect family of true weevils, Curculionidae, includes many agricultural and forest pests. Pissodes strobiPissodes strobiPissodes strobiWolbachiaWolbachi

Summary table for significantly (padj<0.01) increasing and decreasing esterases in fed versus starved males and females including the number of reads in each EST library 01 to14 with greater than 99% nucleotide identity.

<p>Summary table for significantly (padj<0.01) increasing and decreasing esterases in fed versus starved males and females including the number of reads in each EST library 01 to14 with greater than 99% nucleotide identity.</p

Summary information for sequence data mapped to the male mountain pine beetle genome (13).

<p>Summary information for sequence data mapped to the male mountain pine beetle genome (13).</p

Annotated gene transcripts by functional category.

<p>The number of annotated genes within each putative functional category for male beetles (blue bars) and female beetles (pink bars) that had transcript levels either significantly increase or decrease (padj<0.01).</p

Summary table for significantly (padj<0.01) increasing and decreasing transcripts implicated in pheromone flux in fed versus starved males and females including the number of reads in each EST library 01 to14 with greater than 99% nucleotide identity.

<p>Summary table for significantly (padj<0.01) increasing and decreasing transcripts implicated in pheromone flux in fed versus starved males and females including the number of reads in each EST library 01 to14 with greater than 99% nucleotide identity.</p

Summary table for significantly (padj<0.01) increasing and decreasing transcripts implicated in reproductive physiology in fed versus starved males and females including the number of reads in each EST library 01 to14 with greater than 99% nucleotide identity.

<p>Summary table for significantly (padj<0.01) increasing and decreasing transcripts implicated in reproductive physiology in fed versus starved males and females including the number of reads in each EST library 01 to14 with greater than 99% nucleotide identity.</p