Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax (CBS)/University of Sfax, B.P ''1177'', 3018, Sfax, Tunisia.
Laboratory of Molecular Biotechnology of Eukaryotes, Centre of Biotechnology of Sfax, B.P ''1177'', 3018, Sfax, Tunisia.
Plant Physiol Biochem. 2019 Jun;139:366-378. doi: 10.1016/j.plaphy.2019.03.039. Epub 2019 Mar 30.
Catalase proteins play a crucial role in detoxifying hydrogen peroxide, generated during plant growth, and in response to various environmental stresses. Despite their importance, little is known about their localization and expression in wheat. In this study, we identified and characterized a novel peroxisomal catalase gene from Triticum monococcum, designated as TmCAT1. Phylogenetic analysis revealed that TmCAT1 shared high identity with TdCAT1 and other plant catalases belonging to subfamily 1. We predicted the 3D structure model and the oligomerization arrangement of TmCAT1. Besides, we displayed an arrangement in asymmetric unit, which involved interactions including, mainly, residues from N-terminal domain. Interestingly, sequence analysis indicated that TmCAT1, like TdCAT1, had the peroxisomal targeting signal (PTS1) around its C-terminus. Transient expression of TmCAT1-GFP and TdCAT1-GFP in tobacco leaves revealed that the two fused proteins are targeted into peroxisomes. However, the truncated forms lacking the tripeptide QKL remained in the cytosol. Concerning the expression profile analysis, TmCAT1 is expressed especially in leaves in normal condition. On the other hand, it is up-regulated by different stress incorporating salt, osmotic, oxidative, heavy metal and hormones stresses. Functional analysis by heterologous expression in yeast cells showed that TmCAT1 improved tolerance to multiple abiotic stresses. The presence of important cis-regulatory elements in the promoter region of TmCAT1 strongly reinforces the interest of this gene in plant adaptation to various stresses.
过氧化氢酶蛋白在植物生长过程中解毒过氧化氢以及应对各种环境胁迫方面起着至关重要的作用。尽管它们很重要，但人们对其在小麦中的定位和表达知之甚少。在这项研究中，我们从普通小麦中鉴定并表征了一种新的过氧化物酶体过氧化氢酶基因，命名为 TmCAT1。系统发育分析表明，TmCAT1与 TdCAT1 和其他属于亚家族 1 的植物过氧化氢酶具有高度同源性。我们预测了 TmCAT1 的 3D 结构模型和寡聚排列。此外，我们展示了一个不对称单位的排列，其中包括主要来自 N 端结构域的残基之间的相互作用。有趣的是，序列分析表明，与 TdCAT1 一样，TmCAT1 在其 C 末端周围具有过氧化物酶体靶向信号（PTS1）。在烟草叶片中瞬时表达 TmCAT1-GFP 和 TdCAT1-GFP 表明，这两种融合蛋白被靶向到过氧化物酶体中。然而，缺乏三肽 QKL 的截短形式仍留在细胞质中。关于表达谱分析，TmCAT1 在正常条件下主要在叶片中表达。另一方面，它受到不同胁迫的上调，包括盐、渗透、氧化、重金属和激素胁迫。在酵母细胞中的异源表达功能分析表明，TmCAT1 提高了对多种非生物胁迫的耐受性。TmCAT1 启动子区存在重要的顺式调控元件，这强烈增强了该基因在植物适应各种胁迫中的重要性。
