Clusters of orthologous groups (COG) classification of <i>Octodonta nipae</i> unigenes after BLASTx search.

<p>A total of 8,790 proteins were aligned to the COG protein database and classified functionally into 25 classes. Each function class is denoted by different capital letters under the x-axis. The y-axis represents the number of unigenes in a corresponding function class.</p

Phytopathogens Increase the Preference of Insect Vectors to Volatiles Emitted by Healthy Host Plants

Phytopathogen infections not only affect the physiology of host plants but also the preference of insect vectors; these modifications may increase the spread of infection. For this, we determined the effects of “Candidatus Liberibacter asiaticus” (CLas) infection on the preference of an insect vector (Diaphorina citri) for its uninfected or CLas-infected host (Citrus sinensis) and found that the infected vector preferred uninfected citrus, while the uninfected vector preferred infected citrus. We identified two compounds, (Z)-3 hexenyl and methyl salicylate, that were differentially abundant in the volatiles emitted by infected and uninfected citrus and two odorant-binding protein (OBP) genes differentially expressed between infected and uninfected vectors. The results of receptor–ligand binding assays indicated that CLas upregulated OBP A10 expression in the infected vector to target (Z)-3 hexenyl acetate emitted by uninfected citrus and induced citrus to emit more methyl salicylate for binding to OBP2 in the uninfected vector. Our results might be useful for the effective control of CLas infections

qRT-PCR analysis of expression profiles of three randomly selected genes (scavenger receptor, C-type lectin, and cell adhesion molecule) in <i>Octodonta nipae</i> pupae at different time points after parasitization by <i>Tetrastichus brontispae</i>.

<p>The expression levels were normalized to the <i>ribosomal protein S3</i> (reference gene) and the non-parasitized pupae.</p

Differential expression analyses between non-parasitized (NP) and parasitized (P) <i>Octodonta nipae</i> pupae.

<p>The number of up- and down-regulated differentially expressed genes between NP and P libraries was summarized.</p

Transcriptome Immune Analysis of the Invasive Beetle <i>Octodonta nipae</i> (Maulik) (Coleoptera: Chrysomelidae) Parasitized by <i>Tetrastichus brontispae</i> Ferrière (Hymenoptera: Eulophidae)

<div><p>The beetle <i>Octodonta nipae</i> (Maulik) (Coleoptera: Chrysomelidae) is a serious invasive insect pest of palm plants in southern China, and the endoparasitoid <i>Tetrastichus brontispae</i> Ferrière (Hymenoptera: Eulophidae) is a natural enemy of this pest that exhibits great ability in the biocontrol of <i>O. nipae</i>. For successful parasitism, endoparasitoids often introduce or secrete various virulence factors to suppress host immunity. To investigate the effects of parasitization by <i>T. brontispae</i> on the <i>O. nipae</i> immune system, the transcriptome of <i>O. nipae</i> pupae was analyzed with a focus on immune-related genes through Illumina sequencing. <i>De novo</i> assembly generated 49,919 unigenes with a mean length of 598 bp. Of these genes, 27,490 unigenes (55.1% of all unigenes) exhibited clear homology to known genes in the NCBI nr database. Parasitization had significant effects on the transcriptome profile of <i>O. nipae</i> pupae, and most of these differentially expressed genes were down-regulated. Importantly, the expression profiles of immune-related genes were significantly regulated after parasitization. Taken together, these transcriptome sequencing efforts shed valuable light on the host (<i>O. nipae</i>) manipulation mechanisms induced by <i>T. brontispae</i>, which will pave the way for the development of novel immune defense-based management strategies of <i>O. nipae</i>, and provide a springboard for further molecular analyses, particularly of <i>O. nipae</i> invasion.</p></div

Immune-related genes differentially transcribed in <i>Octodonta nipae</i> pupae following parasitization by <i>Tetrastichus brontispae</i>.

<p>*Fold change was calculated as log₂ P/NP. P: parasitized. NP: non-parasitized.</p><p>**FDR: False discovery rate.</p><p>Differentially expressed genes were identified on the basis of FDR≤0.001 and the absolute value of log₂ P/NP≥1.</p

Gene ontology (GO) classification of <i>Octodonta nipae</i> unigenes after BLASTx search.

<p>Histogram presentation of the GO annotation was generated using WEGO software. A total of 13,031 unigenes were assigned at the second level to three GO ontologies: biological process, cellular component, and molecular function. The y-axis indicates the percentage of a certain GO term within each ontology. One unigene could be assigned to more than one GO term.</p

Illumina sequencing and assembly summary of the <i>Octodonta nipae</i> transcriptome.

<p>*Q20 percentage: Percentage of nucleotide error rate under 0.01.</p><p>**N: Uncertain base in the output sequencing data.</p><p>***N50: Median length of all contigs or unigenes.</p

E-value and species distributions of the top BLASTx hits.

<p>The BLASTx search was performed against NCBI non-redundant protein database with an E-value cut-off of 10⁻⁵. A: E-value distribution. B: Species distribution.</p

qRT-PCR validation of ten selected genes in <i>Octodonta nipae</i> pupae which showed differential expression after parasitization by <i>Tetrastichus brontispae</i> on the basis of Illumina sequencing analysis.

<p>The relative expression levels of these unigenes were transformed into the log₂Ratio of parasitized (P) to non-parasitized (NP). The error bars indicate standard deviations of the mean from three independent replications.</p