Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Winchester Str. 2, 35394, Giessen, Germany.
Novosibirsk State Agrarian University, Dobrolubova 160, 630039, Novosibirsk, Russia.
Sci Rep. 2019 Feb 7;9(1):1626. doi: 10.1038/s41598-018-36829-8.
Recent concepts in evolutionary biology suggest that epigenetic mechanisms can translate environmental selection pressures into heritable changes in phenotype. To determine whether experimental selection for a complex trait in insects involves epigenetic modifications, we carried out a generation-spanning experiment using larvae of the greater wax moth Galleria mellonella as a model host to investigate the role of epigenetics in the heritability of resistance against the parasitic fungus Metarhizium robertsii. We investigated differences in DNA methylation, histone acetylation and microRNA (miRNA) expression between an experimentally resistant population and an unselected, susceptible line, revealing that the survival of G. mellonella larvae infected with M. robertsii correlates with tissue-specific changes in DNA methylation and histone modification and the modulation of genes encoding the corresponding enzymes. We also identified miRNAs differentially expressed between resistant and susceptible larvae and showed that these regulatory molecules target genes encoding proteinases and proteinase inhibitors, as well as genes related to cuticle composition, innate immunity and metabolism. These results support our hypothesis that epigenetic mechanisms facilitate, at least in part, the heritable manifestation of parasite resistance in insects. The reciprocal adaptations underlying host-parasite coevolution therefore extend beyond the genetic level to encompass epigenetic modifications.
近期进化生物学领域的概念表明，表观遗传机制可以将环境选择压力转化为表型的可遗传变化。为了确定昆虫复杂性状的实验选择是否涉及表观遗传修饰，我们使用大蜡螟幼虫作为模型宿主进行了一个跨越几代的实验，以研究表观遗传学在对寄生真菌玫烟色棒束孢抗性的遗传中的作用。我们调查了实验抗性种群和未选择的敏感系之间的 DNA 甲基化、组蛋白乙酰化和 microRNA（miRNA）表达的差异，结果表明，感染玫烟色棒束孢的大蜡螟幼虫的存活率与组织特异性的 DNA 甲基化和组蛋白修饰变化以及编码相应酶的基因的调节有关。我们还鉴定了抗性和敏感幼虫之间差异表达的 miRNA，并表明这些调控分子靶向编码蛋白酶和蛋白酶抑制剂的基因，以及与表皮组成、先天免疫和代谢相关的基因。这些结果支持我们的假设，即表观遗传机制至少部分促进了昆虫对寄生虫抗性的可遗传表现。因此，宿主-寄生虫共同进化的相互适应不仅超出了遗传水平，还包括了表观遗传修饰。
