A genomic analysis and transcriptomic atlas of gene expression in Psoroptes ovis reveals feeding- and stage-specific patterns of allergen expression
Burgess, Stewart T.G.; Marr, Edward J.; Bartley, Kathryn; Nunn, Francesca G.; Down, Rachel E.; Weaver, Robert J.; Prickett, Jessica C.; Dunn, Jackie; Rombauts, Stephane; Van Leeuwen, Thomas; Van de Peer, Yves; Nisbet, Alasdair J.
BACKGROUND : Psoroptic mange, caused by infestation with the ectoparasitic mite, Psoroptes ovis, is highly
contagious, resulting in intense pruritus and represents a major welfare and economic concern for the livestock
industry Worldwide. Control relies on injectable endectocides and organophosphate dips, but concerns over
residues, environmental contamination, and the development of resistance threaten the sustainability of this
approach, highlighting interest in alternative control methods. However, development of vaccines and identification
of chemotherapeutic targets is hampered by the lack of P. ovis transcriptomic and genomic resources.
RESULTS : Building on the recent publication of the P. ovis draft genome, here we present a genomic analysis and
transcriptomic atlas of gene expression in P. ovis revealing feeding- and stage-specific patterns of gene expression,
including novel multigene families and allergens. Network-based clustering revealed 14 gene clusters
demonstrating either single- or multi-stage specific gene expression patterns, with 3075 female-specific, 890 malespecific
and 112, 217 and 526 transcripts showing larval, protonymph and tritonymph specific-expression,
respectively. Detailed analysis of P. ovis allergens revealed stage-specific patterns of allergen gene expression, many
of which were also enriched in “fed” mites and tritonymphs, highlighting an important feeding-related allergenicity
in this developmental stage. Pair-wise analysis of differential expression between life-cycle stages identified patterns
of sex-biased gene expression and also identified novel P. ovis multigene families including known allergens and
novel genes with high levels of stage-specific expression.
CONCLUSIONS : The genomic and transcriptomic atlas described here represents a unique resource for the acaridresearch
community, whilst the OrcAE platform makes this freely available, facilitating further community-led
curation of the draft P. ovis genome.
Additional file 1: Table S1. Total number of Illumina Solexa Hi-Seq reads
and the percentage of reads pseudo-mapped for each sample to the P. ovis
transcriptome. Data shown for each of the fifteen RNA samples from P. ovis
life-cycle stages and for “fed” (F) and “starved” (S) mites. AF = adult females,
AM= adult males, L = larvae, P = protonymph, T = tritonymph.
Additional file 2. Gene lists for each life cycle expression cluster.
Additional file 3. IDs and annotation for all genes attributed to each of
the Venn/Euler diagram shown in Fig. 6.
Additional file 4. Gene IDs for all P. ovis genes attributed to each WHO/
IUIS allergen groups.
Additional file 5. Annotated lists of differentially expressed genes
identified from each of the pairwise life-cycle stage comparisons.