Laboratoire Evolution et Diversité Biologique (UMR5174), Institut de Recherche pour le Développement, Centre National pour la Recherche Scientifique, Université Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse, France.
Station d'Ecologie Théorique et Expérimentale (UPR 2001), Centre National pour la Recherche Scientifique, 2 Route du CNRS, F-09200 Moulis, France.
Genes (Basel). 2022 Mar 16;13(3):525. doi: 10.3390/genes13030525.
A parasite's lifestyle is characterized by a critical dependency on its host for feeding, shelter and/or reproduction. The ability of parasites to exploit new host species can reduce the risk associated with host dependency. The number of host species that can be infected by parasites strongly affects their ecological and evolutionary dynamics along with their pathogenic effects on host communities. However, little is known about the processes and the pathways permitting parasites to successfully infect alternative host species, a process known as host shift. Here, we tested whether molecular plasticity changes in gene expression and in molecular pathways could favor host shift in parasites. Focusing on an invasive parasite, , infecting freshwater fish, we conducted a transcriptomic study to compare gene expression in parasites infecting their main host species and two alternative host species. We found 120 significant differentially expressed genes (DEGs) between parasites infecting the different host species. A total of 90% of the DEGs were identified between parasites using the main host species and those using the two alternative host species. Only a few significant DEGs (seven) were identified when comparing parasites from the two alternative host species. Molecular pathways enriched in DEGs and associated with the use of alternative host species were related to cellular machinery, energetic metabolism, muscle activity and oxidative stress. This study strongly suggests that molecular plasticity is an important mechanism sustaining the parasite's ability to infect alternative hosts.
寄生虫的生活方式以对其宿主的喂养、庇护和/或繁殖的严重依赖为特征。寄生虫利用新宿主物种的能力可以降低与宿主依赖相关的风险。寄生虫能够感染的宿主物种数量强烈影响它们的生态和进化动态，以及它们对宿主群落的致病性影响。然而，对于允许寄生虫成功感染替代宿主物种的过程和途径（称为宿主转移），人们知之甚少。在这里，我们测试了基因表达和分子途径中的分子可塑性变化是否可以促进寄生虫的宿主转移。我们专注于一种感染淡水鱼类的入侵寄生虫，进行了一项转录组研究，以比较感染其主要宿主物种和两种替代宿主物种的寄生虫的基因表达。我们在感染不同宿主物种的寄生虫之间发现了 120 个显著差异表达基因 (DEG)。在使用主要宿主物种的寄生虫和使用两种替代宿主物种的寄生虫之间，有 90%的 DEG 被鉴定出来。当比较来自两种替代宿主物种的寄生虫时，只有少数显著的 DEG（7 个）被鉴定出来。在 DEG 中富集的分子途径与替代宿主物种的使用有关，涉及细胞机制、能量代谢、肌肉活动和氧化应激。这项研究强烈表明，分子可塑性是维持寄生虫感染替代宿主能力的重要机制。
