近日，德国科隆大学Michael Melkonian与深圳华大基因Gane Ka-Shu Wong等研究人员合作利用陆地双星绿藻基因组为陆地植物进化提供了新的见解。2019年11月14日出版的《细胞》发表了这项成果。
向陆地环境的过渡（称为陆生化）通常被认为是改变了地球表面的陆地植物区系的进化和多样化的关键事件。通过系统生物学研究，一群最近发现的双星绿藻类（Zygnematophyceae）被认为可能是陆地植物（有胚植物）的近亲。这是出乎意料的，因为双星绿藻的结构很简单，由单细胞或简单的细丝组成，而结构更复杂的轮藻纲（Charophyceae）和绿藻纲（Coleochaetophyceae）反而亲缘关系更远，它们以前被认为是有胚植物的近亲。而最近，另一个普遍的观点（即陆生化出现在有胚植物的共同祖先中）也发生了转变。一些转录组测序结果表明，陆生所需的细胞组分在有胚植物之前便已经在streptophyte藻中进化出来。这些发现显然与这些藻类的水生生活相冲突。在双星绿藻中，一些早期分化的类群是陆生的，这提示这一类群的祖先可能起源于陆地。
研究人员报道并分析了两个早期分化的双星绿藻（Spirogloea muscicola gen. nov.和Mesotaenium endlicherianum）的基因组序列，其与早期分化的有胚植物（苔藓植物）共享栖息地。这些证据表明，增加陆地植物对生物和非生物胁迫（特别是干燥）抗性的基因（即GRAS和PYR/PYL/RCAR）起源于或扩展到双星绿藻与有胚植物的共同祖先，并从土壤细菌的水平基因转移获得。这两个双星绿藻的基因组为将来的研究奠定了基石，从而能够了解植物陆生化的潜在分子机制和过程。
附：英文原文
Title: Genomes of Subaerial Zygnematophyceae Provide Insights into Land Plant Evolution
Author: Shifeng Cheng, Wenfei Xian, Yuan Fu, Birger Marin, Jean Keller, Tian Wu, Wenjing Sun, Xiuli Li, Yan Xu, Yu Zhang, Sebastian Wittek, Tanja Reder, Gerd Günther, Andrey Gontcharov, Sibo Wang, Linzhou Li, Xin Liu, Jian Wang, Huanming Yang, Xun Xu, Pierre-Marc Delaux, Barbara Melkonian, Gane Ka-Shu Wong, Michael Melkonian
Issue&Volume: 2019/11/14
Abstract: The transition to a terrestrial environment, termed terrestrialization, is generallyregarded as a pivotal event in the evolution and diversification of the land plantflora that changed the surface of our planet. Through phylogenomic studies, a groupof streptophyte algae, the Zygnematophyceae, have recently been recognized as thelikely sister group to land plants (embryophytes). Here, we report genome sequencesand analyses of two early diverging Zygnematophyceae (Spirogloea muscicola gen. nov. and Mesotaenium endlicherianum) that share the same subaerial/terrestrial habitat with the earliest-diverging embryophytes,the bryophytes. We provide evidence that genes (i.e., GRAS and PYR/PYL/RCAR) thatincrease resistance to biotic and abiotic stresses in land plants, in particular desiccation,originated or expanded in the common ancestor of Zygnematophyceae and embryophytes,and were gained by horizontal gene transfer (HGT) from soil bacteria. These two Zygnematophyceaegenomes represent a cornerstone for future studies to understand the underlying molecularmechanism and process of plant terrestrialization.
DOI: 10.1016/j.cell.2019.10.019
Source: https://www.cell.com/cell/fulltext/S0092-8674(19)31169-9