Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), Damascus, Syria.
Genomics and Computational Biology Research Group, University of South Wales, Pontypridd, UK.
J Exp Bot. 2018 Mar 24;69(7):1781-1794. doi: 10.1093/jxb/ery027.
Dioxins are highly toxic persistent organic pollutants bioaccumulated by both plants and animals that cause severe developmental abnormalities in humans. We investigated the effects of dioxins on seed development in Arabidopsis. Plants were exposed to various concentrations of the most toxic congener of dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the effects on seed development were analysed in-depth at transcriptome, proteome and metabolome levels. Exposure to dioxin led to generalized effects on vegetative tissues plus a specific set of perturbations to seed development. Mature seeds from TCDD-treated plants had a characteristic 'wrinkled' phenotype, due to a two-thirds reduction in storage oil content. Transcriptional analysis of a panel of genes related to lipid and carbohydrate metabolism was consistent with the observed biochemical phenotypes. There were increases in WRI1 and LEC1 expression but decreases in ABI3 and FUS3 expression, which is puzzling in view of the low seed oil phenotype. This anomaly was explained by increased expression of 20S proteasome components that resulted in a substantial degradation of WRI1 protein, despite the up-regulation of the WRI1 gene. Our findings reveal novel effects of dioxins that lead to altered gene regulation patterns that profoundly affect seed development in Arabidopsis.
二恶英是高度毒性的持久性有机污染物，会在植物和动物体内蓄积，导致人类出现严重的发育异常。我们研究了二恶英对拟南芥种子发育的影响。植物暴露于不同浓度的最毒二恶英同系物 2,3,7,8-四氯二苯并对二恶英（TCDD），并在转录组、蛋白质组和代谢组水平深入分析对种子发育的影响。二恶英暴露导致营养组织的普遍影响，以及对种子发育的特定干扰。TCDD 处理植物的成熟种子具有特征性的“皱缩”表型，这是由于储存油含量减少了三分之二。与脂质和碳水化合物代谢相关的一组基因的转录分析与观察到的生化表型一致。WRI1 和 LEC1 的表达增加，但 ABI3 和 FUS3 的表达减少，考虑到低种子油表型，这令人费解。这种异常可以通过 20S 蛋白酶体成分的表达增加来解释，这导致 WRI1 蛋白大量降解，尽管 WRI1 基因上调。我们的研究结果揭示了二恶英的新作用，导致改变的基因调控模式，从而严重影响拟南芥的种子发育。
