Although epigenetic factors may influence the expression of defense genes in plants, their role in antiviral responses and the impact of viral adaptation and evolution in shaping these interactions are still poorly explored. We used two isolates of turnip mosaic potyvirus with varying degrees of adaptation to Arabidopsis thaliana to address these issues. One of the isolates was experimentally evolved in the plant and presented increased load and virulence relative to the ancestral isolate. The magnitude of the transcriptomic responses was larger for the evolved isolate and indicated a role of innate immunity systems triggered by molecular patterns and effectors in the infection process. Several transposable elements located in different chromatin contexts and epigenetic-related genes were also affected. Correspondingly, mutant plants having loss or gain of repressive marks were, respectively, more tolerant and susceptible to turnip mosaic potyvirus, with a more efficient response against the ancestral isolate. In wild-type plants, both isolates induced similar levels of cytosine methylation changes, including in and around transposable elements and stress-related genes. Results collectively suggested that apart from RNA silencing and basal immunity systems, DNA methylation and histone modification pathways may also be required for mounting proper antiviral defenses and that the effectiveness of this type of regulation strongly depends on the degree of viral adaptation to the host.

中文翻译：

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病毒适应度决定了植物防御反应的转录组和表观基因组重编程的强度。

尽管表观遗传因素可能会影响防御基因在植物中的表达，但它们在抗病毒反应中的作用以及病毒适应性和进化对影响这些相互作用的影响仍未得到很好的研究。我们使用了两种芜菁花叶马铃薯分离株，它们对拟南芥的适应程度不同解决这些问题。其中一种分离株在植物中经过实验进化，相对于祖先分离株而言，其载量和毒力增加。对于进化的分离株，转录组反应的强度更大，并表明了由分子模式和效应子触发的先天免疫系统在感染过程中的作用。位于不同染色质环境和表观遗传相关基因中的几个转座因子也受到影响。相应地，具有抑制标记丧失或获得抑制标记的突变植物分别对芜菁花叶马铃薯多病毒具有更高的耐受性和敏感性，并且对祖先分离株的反应更为有效。在野生型植物中，两种分离物都诱导相似水平的胞嘧啶甲基化变化，包括转座因子内和周围以及与胁迫相关的基因。