To analyze the response of the snail Physella acuta to Echinostoma paraensei, a compatible digenetic trematode, Illumina RNA-seq data were collected from snails with early infection (5 snails at 2 days post-exposure [DPE]) and established infection (4 snails, 8 DPE), and 7 control (unexposed) snails. A reference transcriptome (325,563 transcripts, including 98% of eukaryotic universal single-copy orthologs; BUSCO) and a draft P. acuta genome (employing available genomic Illumina reads; 799,945 scaffolds, includes 88% BUSCO genes) were assembled to guide RNA-seq analyses. Parasite exposure of P. acuta led to 10,195 differentially expressed (DE) genes at 2 DPE and 8,876 DE genes at 8 DPE with only 18% of up-regulated and 22% of down-regulated sequences shared between these time points. Gene ontology (GO) analysis yielded functional annotation of only 1.2% of DE genes but did not indicate major changes in biological activities of P. acuta between 2 and 8 DPE. Increased insights were achieved by analysis of expression profiles of 460 immune-relevant DE transcripts, identified by BLAST and InterProScan. Physella acuta has expanded gene families that encode immune-relevant domains, including CD109/TEP, GTPase IMAP, Limulus agglutination factor (dermatopontin), FReD (≥82 sequences with fibrinogen-related domains), and transcripts that combine C-type lectin (C-LECT) and C1q domains, novel among metazoa. Notably, P. acuta expressed sequences from these immune gene families at all time points, but the assemblages of unique transcripts from particular immune gene families differed between 2 and 8 DPE. The shift in profiles of DE immune genes, from early exposure to parasite establishment, suggests that compatible P. acuta initially respond to infection but switch to express immune genes that likely are less effective against E. paraensei but counter other types of (opportunistic) pathogens and parasites. We propose that the latter expression profile is part of an extended phenotype of E. paraensei, imposed upon P. acuta through parasite manipulation of the host, following successful parasite establishment in the snail after 2 DPE.

为分析蜗牛Physella acuta对兼容的双基因吸虫的棘皮chin虫的反应，从感染较早的蜗牛（暴露后2天[DPE]第2天有5只蜗牛）收集了Illumina RNA-seq数据，并确定了感染（4只蜗牛， 8个DPE）和7个对照（未暴露）蜗牛。组装了一个参考转录组（325,563个转录本，包括98％的真核通用单拷贝直系同源物； BUSCO）和草假单胞菌基因组草案（采用可获得的Illumina基因组读物； 799,945个支架，包括88％BUSCO基因）以指导RNA序列分析。铜绿假单胞菌的寄生虫暴露导致在2个DPE处产生10,195个差异表达（DE）基因，在8个DPE处产生8,876个DE基因，只有18％的上调序列和22％的下调序列在这些时间点之间共享。基因本体论（GO）分析仅产生1.2％的DE基因功能注释，但未显示2-8个DPE之间的Acuta acuta生物活性发生重大变化。通过分析由BLAST和InterProScan鉴定的460种与免疫相关的DE转录本的表达谱，可以提高洞察力。囊螺扩大基因家族是编码免疫相关的领域，包括CD109 / TEP，GTP酶IMAP，鲎凝集因子（dermatopontin），FReD（≥82个具有纤维蛋白原相关结构域的序列），以及结合了C型凝集素（C-LECT）和C1q结构域的转录本，在后生动物中很新颖。值得注意的是，金黄色葡萄球菌在所有时间点都表达了来自这些免疫基因家族的序列，但是来自特定免疫基因家族的独特转录本的组合在2个和8个DPE之间有所不同。从早期接触到寄生虫建立，DE免疫基因谱的变化表明，相容的铜绿假单胞菌起初对感染有反应，但转而表达可能对副猪大肠杆菌无效的免疫基因。但可以对抗其他类型的（机会性）病原体和寄生虫。我们建议，后者表达谱的扩展的表型的部分E. paraensei，强加于P.蚧通过主机的寄生虫操纵，在成功建立寄生虫在蜗牛后2 DPE。