Abstract：
Lead (Pb) affects gene transcription, metabolite biosynthesis and growth in plants. The tung tree (Vernicia fordii) is highly adaptive to adversity, whereas the mechanisms underlying its response to Pb remain uncertain. In this work, transcriptomic and metabolomic analyses were employed to study tung trees under Pb stress. The results showed that the biomass of tung seedlings decreased with increasing Pb doses, and excessive Pb doses resulted in leaf wilting, root rot, and disruption of Pb homeostasis. Under non-excessive Pb stress, a significant change in the expression patterns of flavonoid biosynthesis genes was observed in the roots of tung seedlings, leading to changes in the accumulation of flavonoids in the roots, especially the upregulation of catechins, which can chelate Pb and reduce its toxicity in plants. In addition, Pb-stressed roots showed a large accumulation of VfWRKY55, VfWRKY75, and VfLRR1 transcripts, which were shown to be involved in the flavonoid biosynthesis pathway by gene module analysis. Overexpression of VfWRKY55, VfWRKY75, and VfLRR1 significantly increased catechin concentrations in tung roots, respectively. These data indicate that Pb stress-induced changes in the expression patterns of those genes regulate the accumulation of catechins. Our findings will help to clarify the molecular mechanism of Pb response in plants.
摘要：
铅（Pb）影响基因转录，代谢物在植物中的生物合成和生长。桐树(Verniciafordii)高度适应逆境，而其对铅的反应机制仍不确定。在这项工作中,采用转录组和代谢组学分析研究了铅胁迫下的桐树。结果表明,桐苗生物量随Pb剂量的增加而降低,过量的铅剂量导致叶片枯萎，根腐病,和铅稳态的破坏。在非过量铅胁迫下，在桐苗根中观察到类黄酮生物合成基因的表达模式发生了显着变化，导致根中类黄酮积累的变化，尤其是儿茶素的上调，可以螯合铅并降低其在植物中的毒性。此外,Pb胁迫的根部显示出大量积累的VfWRKY55，VfWRKY75和VfLRR1转录本，通过基因模块分析显示其参与类黄酮生物合成途径。VfWRKY55、VfWRKY75和VfLRR1的过表达显著增加了桐根中儿茶素的浓度,分别。这些数据表明，铅胁迫诱导的这些基因表达模式的变化调节儿茶素的积累。我们的发现将有助于阐明植物对铅响应的分子机制。
