摘要
Emerging infectious diseases are significant threats to wildlife conservation, yet the impacts of pathogen exposure and infection can vary widely among host species. As such, conservation biologists and disease ecologists have increasingly aimed to understand species-specific host susceptibility using molecular methods. In particular, comparative gene expression assays have been used to contrast the transcriptomic responses of disease-resistant and disease-susceptible hosts to pathogen exposure. This work usually assumes that the gene expression responses of disease-resistant species will reveal the activation of molecular pathways contributing to host defence. However, results often show that disease-resistant hosts undergo little gene expression change following pathogen challenge. Here, we discuss the mechanistic implications of these “null” findings and offer methodological suggestions for future molecular studies of wildlife disease. First, we highlight that muted transcriptomic responses with minimal immune system recruitment may indeed be protective for nonsusceptible hosts if they limit immunopathology and promote pathogen tolerance in systems where susceptible hosts suffer from genetic dysregulation. Second, we argue that overly narrow investigation of responses to pathogen exposure may overlook important, constitutively active molecular pathways that underlie species-specific defences. Finally, we outline alternative study designs and approaches that complement interspecific transcriptomic comparisons, including intraspecific gene expression studies and genomic methods to detect signatures of selection. Collectively, these insights will help ecologists extract maximal information from conservation-relevant transcriptomic data sets, leading to a deeper understanding of host defences and, ultimately, the implementation of successful conservation interventions.
摘要译文
新兴传染病对野生动物保护的重要威胁，但病原体暴露和感染的影响可能在宿主物种中很大。因此，保护生物学家和疾病生态学家越来越旨在使用分子方法来了解特异性宿主敏感性。特别地，对比较基因表达测定已被用于将抗病和易感性宿主对病原体暴露的转录组反应造影。这项工作通常假设抗病物种的基因表达反应将揭示有助于宿主防御的分子途径的激活。然而，结果通常表明，在病原体攻击后，抗病宿主会经历几乎没有基因表达的变化。在这里，我们讨论了这些“空”调查结果的机制意义，并为未来野生动物疾病的分子研究提供了方法论建议。首先，我们强调，如果它们限制免疫病理学并促进易感宿主患有遗传失调的系统中的病原体耐受性，则突出柔软的转录组织反应可能对不可批诊的宿主进行保护，确实是保护宿主的保护性。其次，我们认为对病原体暴露的反应过度缩小调查可能忽略了底部特异性防御的重要性，组成的活性分子途径。最后，我们概述了替代研究设计和接近的补蛋白特异性转录组的比较，包括用于检测选择的签名的内部基因表达研究和基因组方法。统称，这些见解将帮助生态学家从保护相关的转录组数据集中提取最大信息，从而更深入地了解寄主防御，并最终实现成功的保护干预措施。
Evan A. Eskew[1];Devaughn Fraser[2];Maarten J. Vonhof[3];Malin L. Pinsky[1];Brooke Maslo[1]. Host gene expression in wildlife disease: making sense of species-level responses[J]. Molecular Ecology, 2021,30(24): 6517-6530