DNA methylation is an important epigenetic mark required for proper gene expression and silencing of transposable elements. DNA methylation patterns can be modified by environmental factors such as pathogen infection, where modification of DNA methylation can be associated with plant resistance. To counter the plant defense pathways, pathogens produce effectors molecule, several of which act as proteasome inhibitors. Here we investigated the effect of proteasome inhibition by the bacterial virulence factor Syringolin A on genome-wide DNA methylation. We show that Syringolin A treatment results in an increase of DNA methylation at centromeric and pericentromeric regions of Arabidopsis chromosomes. We identify several CHH DMRs that are enriched in the proximity of transcriptional start sites. Syringolin A treatment does not result in significant changes in small RNA composition. However, significant changes in genome transcriptional activity can be observed, including a strong upregulation of resistance genes that are located on chromosomal arms. We hypothesize that DNA methylation changes could be linked to the upregulation of some atypical members of the de novo DNA methylation pathway: AGO3, AGO9 and DRM1. Our data suggests that modification of genome-wide DNA methylation resulting from an inhibition of the proteasome by bacterial effectors could be part of a epi-genomic arms race against pathogens.

中文翻译：

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丁香假单胞菌毒力因子Syringolin A抑制蛋白酶体时的甲基化动力学。

DNA甲基化是适当的基因表达和转座因子沉默所需的重要表观遗传标记。DNA甲基化模式可以通过环境因素（例如病原体感染）进行修饰，其中DNA甲基化的修饰可能与植物抗性相关。为了对抗植物防御途径，病原体产生效应子分子，其中一些充当蛋白酶体抑制剂。在这里，我们研究了细菌毒力因子丁香林A对蛋白酶体的抑制作用对全基因组DNA甲基化的影响。我们表明，丁香酚素A处理导致拟南芥染色体着丝粒和着丝粒区域DNA甲基化的增加。我们确定了几个CHH DMRs丰富的转录起始位点附近。丁香脂素A处理不会导致小RNA组成的显着变化。但是，可以观察到基因组转录活性的显着变化，包括位于染色体臂上的抗性基因的强烈上调。我们假设DNA甲基化的变化可能与从头DNA甲基化途径的一些非典型成员AGO3，AGO9和DRM1的上调有关。我们的数据表明，由细菌效应子抑制蛋白酶体导致的全基因组DNA甲基化修饰可能是抗病原体的表观基因组军备竞赛的一部分。我们假设DNA甲基化的变化可能与从头DNA甲基化途径的一些非典型成员AGO3，AGO9和DRM1的上调有关。我们的数据表明，由细菌效应子抑制蛋白酶体导致的全基因组DNA甲基化修饰可能是抗病原体的表观基因组军备竞赛的一部分。我们假设DNA甲基化的变化可能与从头DNA甲基化途径的一些非典型成员AGO3，AGO9和DRM1的上调有关。我们的数据表明，细菌效应子对蛋白酶体的抑制导致全基因组DNA甲基化的修饰可能是抗病原体的表观基因组军备竞赛的一部分。