Abstract

DNA methylation is one epigenetic strategy for gene regulation in living organisms. In this study, the expression of soybean isoflavone synthase (GmIFS) transgene in T0 transgenic wheat plants was investigated at the RNA and the final product genestin level. T0 plants showed variations in the GmIFS expression. Methylation status of the exogenous promoters (35S or Oleocin (OL)) proximal sequence was investigated in T0 plants using bisulphite sequencing to disclose their methylation in parallel with the GmIFS level of expression. Results concluded that the high GmIFS expressers of T0 plants exhibited high methylation of exogenous promoter proximal sequences as well as low expression of DNA methyltransferases (Mets). Variation in GmIFS was associated with the level of methylation in the 35S or OL promoters. High expression of GmIFS was negatively correlated with methylation level of 35S and OL promoter proximal regions. In 35S promoter, methylation level of the CpG sites –56 and –88 is strongly linked to GmIFS expression and is involved in the regulation of GmIFS gene. In OL promoter, the CpG site could be involved in the regulation of the GmIFS. Wheat Met3 expression varied among T0 transgenic plants. Its expression profile could explain the regulation of GmIFS transgene by methylation.

中文翻译：

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外源启动子的甲基化调节T0转基因小麦（Triticum aestivum）的大豆异黄酮合酶（GmIFS）转基因

摘要

DNA甲基化是生物体内基因调控的一种表观遗传策略。在这项研究中，研究了大豆异黄酮合酶（GmIFS）转基因在T0转基因小麦植株中的RNA和最终产物基因表达水平的表达。T0植物显示出GmIFS表达的变化。使用亚硫酸氢盐测序在T0植物中研究了外源启动子（35S或Oleocin（OL））近端序列的甲基化状态，以揭示其甲基化与GmIFS表达水平的平行性。结果得出结论，T0植物的高GmIFS表达体表现出外源启动子近端序列的高甲基化以及DNA甲基转移酶（Mets）的低表达。GmIFS的变化与35S或OL启动子中的甲基化水平有关。GmIFS的高表达与35S和OL启动子近端区域的甲基化水平呈负相关。在35S启动子中，CpG位点–56和–88的甲基化水平与GmIFS表达密切相关，并参与GmIFS基因的调控。在OL启动子中，CpG位点可能参与GmIFS的调控。在T0转基因植物中，小麦Met3表达有所不同。它的表达谱可以解释甲基化对GmIFS转基因的调控。