Abstract：
Overgrazing generally induces dwarfism in grassland plants, and these phenotypic traits could be transmitted to clonal offspring even when overgrazing is excluded. However, the dwarfism-transmitted mechanism remains largely unknown, despite generally thought to be enabled by epigenetic modification. To clarify the potential role of DNA methylation on clonal transgenerational effects, we conducted a greenhouse experiment with Leymus chinensis clonal offspring from different cattle/sheep overgrazing histories via the demethylating agent 5-azacytidine. The results showed that clonal offspring from overgrazed (by cattle or sheep) parents were dwarfed and the auxin content of leaves significantly decreased compared to offspring from no-grazed parents\'. The 5-azaC application generally increased the auxin content and promoted the growth of overgrazed offspring while inhibited no-grazed offspring growth. Meanwhile, there were similar trends in the expression level of genes related to auxin-responsive target genes (ARF7, ARF19), and signal transduction gene (AZF2). These results suggest that DNA methylation leads to overgrazing-induced plant transgenerational dwarfism via inhibiting auxin signal pathway.
摘要：
过度放牧通常会在草地植物中引起侏儒症，即使排除过度放牧，这些表型性状也可以传播给克隆后代。然而,侏儒症的传播机制在很大程度上仍然未知，尽管通常认为是通过表观遗传修饰实现的。为了阐明DNA甲基化对克隆代际效应的潜在作用，我们通过去甲基化剂5-氮杂胞苷对来自不同牛/羊过度放牧历史的羊草克隆后代进行了温室实验。结果表明，与未放牧父母的后代相比，来自过度放牧（牛或羊）父母的克隆后代相形见绌，叶片的生长素含量显着降低。5-azaC的施用通常会增加生长素含量，促进过度放牧后代的生长，同时抑制未放牧后代的生长。同时,与生长素应答靶基因（ARF7，ARF19）相关的基因表达水平也有相似的趋势，和信号转导基因(AZF2)。这些结果表明，DNA甲基化通过抑制生长素信号通路导致过度放牧诱导的植物跨代侏儒症。
