Transcriptome-wide comparison of selenium hyperaccumulator and nonaccumulator Stanleya species provides new insight into key processes mediating the hyperaccumulation syndrome

First author: Jiameng Wang; Affiliations: Colorado State University (科罗拉多州大学): Fort Collins, USA

Corresponding author: Elizabeth A. H. Pilon-Smits

To obtain better insight into the mechanisms of selenium (硒) hyperaccumulation in Stanleya pinnata, transcriptome-wide differences in root and shoot gene expression levels were investigated in S. pinnata and related nonaccumulator Stanleya elata grown with or without 20 μm selenate. Genes predicted to be involved in sulphate/selenate (硫酸盐或硒酸盐) transport and assimilation (同化) or in oxidative stress resistance (glutathione-related genes 谷胱甘肽相关基因 and peroxidases 过氧化物酶) were among the most differentially expressed between species; many showed constitutively elevated expression in S. pinnata. A number of defence-related genes predicted to mediate synthesis and signalling of defence hormones jasmonic acid (JA, reported to induce sulphur assimilatory 硫同化 and glutathione biosynthesis genes), salicylic acid (SA) and ethylene were also more expressed in S. pinnata than S. elata. Several upstream signalling genes that up-regulate defence hormone synthesis showed higher expression in S. pinnata than S. elata and might trigger these selenium-mediated defence responses. Thus, selenium hyperaccumulation and hypertolerance in S. pinnata may be mediated by constitutive, up-regulated JA, SA and ethylene-mediated defence systems, associated with elevated expression of genes involved in sulphate/selenate uptake and assimilation or in antioxidant activity. Genes pinpointed in this study may be targets of genetic engineering of plants that may be employed in biofortification (生物强化) or phytoremediation (植物修复).

为了研究Stanleya pinnata能够超富集硒的机理，作者对Stanleya pinnata及其同属不积累硒的植物Stanleya elata进行20μm硒处理及空白对照，进而对其根和茎进行转录组测序、比较研究。研究显示参与硫酸盐或硒酸盐转运和同化，以及演化胁迫响应相关基因即谷胱甘肽相关基因和过氧化物酶在这两个物种间差异表达最为显著，这其中许多基因在S. pinnata中呈组成型表达提升。另外，许多抗性相关基因，诸如一些抗性激素茉莉酸JA、水杨酸SA和乙烯合成和信号转导的基因在S. pinnata中表达量更高，其中JA被报道能够诱导硫同化和谷胱甘肽生物合成基因的表达。一些上调抗性激素合成的上游信号基因在S. pinnata中具有更高的表达量，可能会诱导硒介导的防御响应。因此，S. pinnata植物对硒的超富集和超抗性可能由组成型的及上调的JA、SA和乙烯介导的防御系统所调控，并与参与硫酸盐或硒酸盐的吸收和同化及抗氧化活性相关基因的表达量上调相关。本文所鉴定的这些基因可能为将来生物强化和植物修复配置植物的遗传工程提供靶基因。

通讯：Elizabeth A. H. Pilon-Smits (http://www.biology.colostate.edu/people/epsmits/)

个人简历：1992年，荷兰乌得勒支大学，博士，方向：景天酸代谢演化；1992-1994年，荷兰乌得勒支大学，博士后，方向：转基因植物（产糖果聚糖和海藻糖）的干旱抗性。

研究方向：植物对硒的抗性和富集。

doi: 10.1111/pbi.12897

Journal: Plant Biotechnology Journal

Published date: 14 March, 2018

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