There is a rising public concern on accumulation of harmful pesticides in environment and crops. Epigenetic alteration caused by environmental contaminants is one of the key factors in the etiology of environmentally-associated diseases. Growing evidence shows that harmful pesticide atrazine (ATZ) has a profound effect on DNA methylation in human genome, however, little is known about the epigenetic mechanism underlying ATZ accumulation and degradation in plants, particularly in edible plants growing in the ATZ-contaminated areas. This study investigated the atrazine elimination that was mediated by DNA methylation and histone modification in the food crop rice. Studies with two mutant Osmet1-1/2 defective in the genomic CG DNA methylation show significantly lower accumulation of atrazine than its wild-types. Profiling methylome and transcriptome of ATZ-exposed Osmet1 and wild-type identified many differentially methylated loci (≥2 fold change, p < 0.05), which were associated with activation of genes responsible for atrazine degradation in plants. Three demethylated loci OsGTF, OsHPL1 and OsGLH were expressed in eukaryotic yeast cells and found to eliminate a marked proportion of ATZ in growth environments by 48%, 43% and 32%, respectively, whereas the increased ATZ-degraded products were characterized using UPLC/Q-TOF-MS/MS. These results suggest that activation of the loci mediated by ATZ-induced hypomethylation could be responsible for the removal of ATZ in rice. Our work helps understand a new regulatory mechanism underlying the atrazine degradation in crops which may potentially reduce the environmental risks to human health through food chain.

公众日益关注有害农药在环境和农作物中的积累。由环境污染物引起的表观遗传改变是与环境有关的疾病的病因学中的关键因素之一。越来越多的证据表明，有害农药at去津（ATZ）对人类基因组中的DNA甲基化具有深远的影响，然而，人们对ATZ在植物中积累和降解的表观遗传机制知之甚少，特别是在ATZ污染地区生长的可食用植物中。这项研究调查了粮食作物水稻中由DNA甲基化和组蛋白修饰介导的at去津消除。用两个突变体Osmet1-1 / 2进行研究基因组CG DNA甲基化的缺陷表明，r去津的积累比其野生型低得多。ATZ暴露的Osmet1和野生型的甲基化分析和转录组分析鉴定出许多差异甲基化的基因座（≥2倍变化，p <0.05），这与植物中负责at去津降解的基因的激活有关。三个脱甲基位点OsGTF，OsHPL1和OsGLH它们在真核酵母细胞中表达，并发现在生长环境中消除了显着比例的ATZ，分别消除了48％，43％和32％，而使用UPLC / Q-TOF-MS / MS对增加的ATZ降解产物进行了表征。这些结果表明由ATZ诱导的低甲基化介导的基因座的激活可能是水稻中ATZ去除的原因。我们的工作有助于理解一种新的监管机制，该机制是农作物the去津降解的基础，它可能通过食物链降低对人类健康的环境风险。