Appearance and role of CuZnSOD proteins during early land plant evolution

铜锌超氧化物歧化酶（CuZnSOD）蛋白出现在大约24亿年前的大氧化事件时期。在高等植物中存在三种室特异性蛋白质，即细胞质、塑性和过氧化物酶体蛋白质，其中细胞质形式似乎首先进化，因为它已经存在于淡水藻Chara braunii中。我们发现拟南芥细胞质形式对胚胎发生至关重要，并且CSD1蛋白具有两种功能：一方面作为抗氧化酶，另一方面作为核转录调节剂。淡水藻类中CuZnSOD的出现表明，它可能代表了一种早期的分子适应，使其能够向陆地过渡。本研究旨在揭示CuZnSOD在早期陆生植物胚胎发生过程中的作用以及通过调节苯丙素代谢对非生物胁迫耐受性的调节作用。本文以多形地药和小立壶菌为研究对象，揭示了胞质CuZnSOD在植物陆地化过程中的双重作用。

Copper Zinc Superoxide Dismutase (CuZnSOD) proteins appeared around the time of the Great Oxidation Event around 2.4 billion years ago. In higher plants three compartment specific proteins are present, namely a cytosolic, plastidic and peroxisomal protein, of which the cytosolic form appears to have evolved first since it is already present in the freshwater algea Chara braunii. We found that the cytosolic form in Arabidopsis is essential for embryogenesis and that the CSD1 protein has two functions: on the one hand as an antioxidant enzyme and on the other as a nuclear transcriptional regulator. The appearance of CuZnSOD in freshwater algae indicate that it might represent an early molecular adaptation to enable the transition to land. Here we aim at revealing the role of CuZnSOD during embryogenesis and the regulation of abiotic stress tolerance in early land plants by modulating phenylpropanoid metabolism. We focus on Marchantia polymorpha and Physcomitrella patens to unravel the dual role of the cytosolic CuZnSOD during plant terrestrialization.