McTaggart Seanna J, Cézard Timothée, Garbutt Jennie S, Wilson Phil J, Little Tom J
Institute of Evolutionary Biology, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, EH9 3JT, UK.
Edinburgh Genomics, Ashworth Laboratories, University of Edinburgh, Edinburgh, EH9 3JT, UK.
BMC Genomics. 2015 Aug 28;16(1):643. doi: 10.1186/s12864-015-1838-0.
Infection outcome in some coevolving host-pathogens is characterised by host-pathogen genetic interactions, where particular host genotypes are susceptible only to a subset of pathogen genotypes. To identify candidate genes responsible for the infection status of the host, we exposed a Daphnia magna host genotype to two bacterial strains of Pasteuria ramosa, one of which results in infection, while the other does not. At three time points (four, eight and 12 h) post pathogen exposure, we sequenced the complete transcriptome of the hosts using RNA-Seq (Illumina).
We observed a rapid and transient response to pathogen treatment. Specifically, at the four-hour time point, eight genes were differentially expressed. At the eight-hour time point, a single gene was differentially expressed in the resistant combination only, and no genes were differentially expressed at the 12-h time point.
We found that pathogen-associated transcriptional activity is greatest soon after exposure. Genome-wide resistant combinations were more likely to show upregulation of genes, while susceptible combinations were more likely to be downregulated, relative to controls. Our results also provide several novel candidate genes that may play a pivotal role in determining infection outcomes.
在一些共同进化的宿主 - 病原体中，感染结果的特征是宿主 - 病原体基因相互作用，即特定的宿主基因型仅对病原体基因型的一个子集敏感。为了鉴定负责宿主感染状态的候选基因，我们将大型溞宿主基因型暴露于两种枝原体巴斯德氏菌菌株，其中一种会导致感染，而另一种则不会。在病原体暴露后的三个时间点（4小时、8小时和12小时），我们使用RNA测序（Illumina）对宿主的完整转录组进行了测序。
我们观察到对病原体处理有快速且短暂的反应。具体而言，在4小时时间点，有8个基因差异表达。在8小时时间点，仅在抗性组合中有一个基因差异表达，而在12小时时间点没有基因差异表达。
我们发现病原体相关的转录活性在暴露后不久最大。相对于对照，全基因组抗性组合更可能显示基因上调，而敏感组合更可能被下调。我们的结果还提供了几个可能在确定感染结果中起关键作用的新候选基因。
