PDF(Pubmed)
Abstract：
Zinc (Zn) is an essential micronutrient but can be cytotoxic when present in excess. Plants have evolved mechanisms to tolerate Zn toxicity. To identify genetic loci responsible for natural variation of plant tolerance to Zn toxicity, we conduct genome-wide association studies for root growth responses to high Zn and identify 21 significant associated loci. Among these loci, we identify Trichome Birefringence (TBR) allelic variation determining root growth variation in high Zn conditions. Natural alleles of TBR determine TBR transcript and protein levels which affect pectin methylesterification in root cell walls. Together with previously published data showing that pectin methylesterification increase goes along with decreased Zn binding to cell walls in TBR mutants, our findings lead to a model in which TBR allelic variation enables Zn tolerance through modulating root cell wall pectin methylesterification. The role of TBR in Zn tolerance is conserved across dicot and monocot plant species.
摘要：
锌(Zn)是必需的微量营养素,但是当过量存在时可以是细胞毒性的。植物已经进化了耐受Zn毒性的机制。为了确定负责植物对锌毒性的耐受性的自然变异的遗传基因座，我们对根生长对高锌的反应进行了全基因组关联研究，并确定了21个重要的相关基因座。在这些基因座中，我们确定了在高锌条件下决定根生长变化的毛状双折射（TBR）等位基因变异。TBR的天然等位基因决定了影响根细胞壁中果胶甲酯化的TBR转录物和蛋白质水平。结合先前发表的数据，显示果胶甲酯化增加与TBR突变体中Zn与细胞壁的结合减少，我们的发现导致了一个模型，其中TBR等位基因变异通过调节根细胞壁果胶甲酯化作用来实现Zn耐受性。TBR在锌耐受性中的作用在双子叶植物和单子叶植物物种中是保守的。
