Land plant evolution is a major leap in the history of life that took place during the Neoproterozoic Era (~800 Mya). Charophyceae, a class of rhyzophytic green algae emerged as a land plant with innovations in biochemical, cytological and developmental adaptations and played a crucial role in establishing life on the land. One such striking architectural innovation is root that experience harsh environmental assaults such as floods, waterlogging and therefore is the epicentre for anaerobic fermentation, which produces toxic acetaldehyde. Here, we show that such produced acetaldehyde makes N-ethyl-adducts on a central component of translation machinery aa-tRNA. The Plant kingdom is unique among life forms in possessing two chirality-based proofreading systems represented by D-aminoacyl-tRNA deacylases (DTD1 and DTD2), derived from Bacteria and Archaea. We identified a unique role of archaeal derived chiral proofreading module DTD2 that selectively deacylates N-ethyl-D-aminoacyl-tRNAs (NEDATs) in plants. NEDAT deacylase function is exclusive to DTD2, as no other proofreading modules with similar substrates like canonical DTD1 and peptidyl-tRNA hydrolase (PTH) can clear NEDATs. Thus, the study elucidates the cause of hypersensitivity of DTD2 knockout plants for both ethanol and acetaldehyde. We further show NEDAT elimination is rooted in Archaea which possess the biosynthesis machinery for ethanol fermentation similar to plants. While absent in other algal branches, DTD2 can be identified in plants from land plant ancestors-Charophytes onwards. DTD2 is the only gene that has only archaeal origin among the genes ascribed for architectural and genomic innovations that happened in the land plant ancestors. The work has uncovered an important gene transfer event from methanogenic archaea to the charophytes in the oldest terrestrial ecosystem bog that contains excess of D-amino acids and deprived of oxygen.

中文翻译：

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招募古细菌DTD是陆地植物出现的关键事件

陆生植物的进化是新元古代（约800 Mya）时代生命史上的一次重大飞跃。风铃草科是一类有根真菌的绿藻，是一种具有生化，细胞学和发育适应性创新的陆生植物，在建立陆地生物方面起着至关重要的作用。这种引人注目的建筑创新之一就是遭受洪水，涝灾等严酷的环境袭击的根源，因此是产生有毒乙醛的厌氧发酵的中心。在这里，我们显示出这种产生的乙醛在翻译机器aa-tRNA的中心成分上产生N-乙基加合物。植物王国在生命形式中是独一无二的，它具有两个基于手性的校对系统，它们以D-氨酰基-tRNA脱酰基酶（DTD1和DTD2）为代表，来源于细菌和古细菌。我们确定了古细菌衍生的手性校对模块DTD2的独特作用，该模块选择性地使植物中的N-乙基-D-氨基酰基-tRNA（NEDATs）脱酰基。NEDAT脱酰基酶功能是DTD2独有的，因为没有其他具有相似底物的校对模块，例如规范的DTD1和肽基-tRNA水解酶（PTH）可以清除NEDAT。因此，该研究阐明了DTD2敲除植物对乙醇和乙醛过敏的原因。我们进一步表明，消除NEDAT根源于古细菌，古细菌具有与植物相似的乙醇发酵生物合成机制。虽然在其他藻类分支中不存在，但从陆地植物祖先-Charophytes以后的植物中都可以鉴定出DTD2。DTD2是在陆地植物祖先中发生的建筑和基因组创新归因基因中唯一唯一具有古细菌起源的基因。这项工作发现了一个重要的基因转移事件，从甲烷化古细菌到最古老的陆地生态系统沼泽中的轮藻，其中含有过量的D-氨基酸并且缺乏氧气。