Institut Jean-Pierre Bourgin, Université Paris-Saclay, INRAE, AgroParisTech, 78000 Versailles, France.
Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany.
Metallomics. 2020 Jun 24;12(6):840-859. doi: 10.1039/d0mt00043d.
Trace metal elements are essential for plant growth but become toxic at high concentrations, while some non-essential elements, such as Cd and As, show toxicity even in traces. Thus, metal homeostasis is tightly regulated in plants. Plant species colonising metalliferous soils have evolved mechanisms to hypertolerate metals and, in rare cases, can hyperaccumulate them in excess amounts in their shoots. The molecular mechanisms of metal hypertolerance and hyperaccumulation are likely derived from alterations in the basic mechanisms involved in general metal homeostasis. Genes involved in metal transport, synthesis of metal chelators and oxidative stress responses are constitutively and highly expressed in metal hypertolerant and hyperaccumulator species. Plant specialized metabolites and cell wall components have been proposed as major players in these mechanisms. In addition, the high intra-specific natural variation of metal hypertolerance and hyperaccumulation suggests that various molecular mechanisms might be involved in the evolution of these traits. To date, the potential of wild plant populations as systems to study metal tolerance and hyperaccumulation has not been fully exploited. The advent of next-generation sequencing (NGS) has enabled the study of non-model species, providing an opportunity to study natural populations and new tolerant and/or hyperaccumulating species, and will provide new insights into metal tolerance and hyperaccumulation. In this review we highlight background knowledge about metal tolerance and hyperaccumulation in plants and the current state-of-the-art techniques to study and identify the underlying mechanisms of metal hypertolerance and hyperaccumulation. We also outline for the reader the importance of the multidisciplinarity of this research field and how the integration of multiomic approaches will benefit facing the future scientific challenges.
痕量金属元素对植物生长至关重要，但在高浓度下会变得有毒，而一些非必需元素，如 Cd 和 As，即使在痕量下也表现出毒性。因此，植物中的金属内稳性受到严格调控。在富含金属的土壤中定殖的植物物种已经进化出机制来耐受金属，在极少数情况下，它们可以在其地上部分过度积累这些金属。金属耐受力和超积累的分子机制可能源于参与一般金属内稳性的基本机制的改变。参与金属转运、金属螯合剂合成和氧化应激反应的基因在金属耐受力和超积累物种中持续且高度表达。植物特化代谢物和细胞壁成分被认为是这些机制的主要参与者。此外，金属耐受力和超积累的高种内自然变异表明，各种分子机制可能参与了这些特征的进化。迄今为止，野生植物种群作为研究金属耐受性和超积累的系统的潜力尚未得到充分利用。下一代测序（NGS）的出现使得研究非模式物种成为可能，为研究自然种群和新的耐受和/或超积累物种提供了机会，并将为金属耐受性和超积累提供新的见解。在这篇综述中，我们强调了植物金属耐受性和超积累的背景知识以及当前研究金属耐受力和超积累的机制的最先进技术。我们还为读者概述了这个研究领域的多学科性的重要性，以及多组学方法的整合将如何有助于应对未来的科学挑战。
