Long terminal repeat (LTR) retrotransposons are important pathways to examine various genome reorganizations based on environmental factors. The maize genome is one of the best representative examples. The aim of this study was to examine humic acid (HA) protective effects on genomic template stability (GTS) and LTR retrotransposon polymorphisms in corn seeds subjected to zinc (Zn) and iron (Fe) stress. In this study, maize seedlings were exposed to three doses (20, 40, and 60 mM) of ZnSO4·7H2O and FeSO4 and their combinations at 1500 ppm (0.075 g) HA. Inter-retrotransposon amplified polymorphism and retrotransposon-microsatellite amplified polymorphism techniques were used for genetic analyses. Results indicated that in all doses used, Zn and Fe increased retrotransposon polymorphisms and decreased the percentage of GTS via DNA damage. However, treatment of HA together with Zn and Fe resulted in decreased DNA damage and retrotransposon polymorphisms and increased GTS. These observations suggest that HA can be applied to reduce toxic effects in agricultural areas polluted with heavy metals.

中文翻译：

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腐植酸对玉米 (Zea mays L.) 基因组中锌和铁引起的反转录转座子多态性的影响

长末端重复 (LTR) 反转录转座子是检查基于环境因素的各种基因组重组的重要途径。玉米基因组是最好的代表性例子之一。本研究的目的是检验腐植酸 (HA) 对受到锌 (Zn) 和铁 (Fe) 胁迫的玉米种子中基因组模板稳定性 (GTS) 和 LTR 逆转录转座子多态性的保护作用。在这项研究中，玉米幼苗暴露于三种剂量（20、40 和 60 mM）的 ZnSO4·7H2O 和 FeSO4 及其组合，浓度为 1500 ppm (0.075 g) HA。反转录转座子间扩增多态性和反转录转座子-微卫星扩增多态性技术用于遗传分析。结果表明，在所有使用的剂量中，锌和铁通过 DNA 损伤增加了逆转录转座子多态性并降低了 GTS 的百分比。然而，HA 与 Zn 和 Fe 一起处理导致 DNA 损伤减少和逆转录转座子多态性减少以及 GTS 增加。这些观察结果表明，HA 可用于减少被重金属污染的农业区的毒性作用。