PDF(Pubmed)
Abstract：
Mercury (Hg) toxicity is an increasing problem worldwide, with a negative impact on the environment and living organisms including both animals and plants. In this study, we analyzed molecular and biochemical changes related to Hg toxicity in wheat (Triticum aestivum L.) seedlings. Seven-day-old seedlings were exposed to various concentrations (5, 10, and 20 µM) of HgCl2 for 24 and 48 h. Our results showed that HgCl2 treatments led to an increase in the Hg content of wheat leaves in a time- and concentration-dependent manner. Furthermore, significant increases were observed in hydrogen peroxide, malondialdehyde, and proline contents in response to Hg toxicity. While all HgCl2 treatments decreased the level of superoxide dismutase (SOD), the level of catalase (CAT) was reduced only in seedlings exposed to 5 µM of HgCl2. Mercury stress caused a decline in the expression of Cu/Zn-SOD, Fe-SOD, TaWRKY19, and TaDREB1 genes at both exposure times. On the other hand, 10 and 20 µM HgCl2 treatments caused significant induction (1.9 to 6.1-fold) in the expression of the CAT gene in wheat leaves. The mRNA level of the Mn-SOD and TaWRKY2 genes showed different patterns depending on the concentration and exposure period of HgCl2. In conclusion, the findings of this work demonstrate that Hg toxicity causes oxidative damage in wheat seedlings and changes the expression of some genes encoding WRKY and DREB transcription factor families, which have important functions in abiotic stress response.
摘要：
汞（Hg）毒性是全球日益严重的问题，对环境和包括动物和植物在内的生物体产生负面影响。在这项研究中,我们分析了小麦（TriticumaestivumL.）幼苗中与汞毒性相关的分子和生化变化。将7天大的幼苗暴露于各种浓度（5、10和20µM）的HgCl2中24小时和48小时。我们的结果表明，HgCl2处理导致小麦叶片中Hg含量以时间和浓度依赖性方式增加。此外，在过氧化氢中观察到显著增加，丙二醛，和脯氨酸含量对汞毒性的反应。虽然所有HgCl2处理都降低了超氧化物歧化酶（SOD）的水平，过氧化氢酶（CAT）的水平仅在暴露于5µMHgCl2的幼苗中降低。汞胁迫导致Cu/Zn-SOD表达下降,Fe-SOD,TaWRKY19和TaDREB1基因在两个暴露时间。另一方面,10和20µMHgCl2处理在小麦叶片中引起CAT基因表达的显着诱导（1.9至6.1倍）。Mn-SOD和TaWRKY2基因的mRNA水平根据HgCl2的浓度和暴露时间而显示出不同的模式。总之,这项工作的发现表明，汞毒性会导致小麦幼苗的氧化损伤，并改变一些编码WRKY和DREB转录因子家族的基因的表达，在非生物应激反应中具有重要作用。
