Genomes of Subaerial Zygnematophyceae Provide Insights into Land Plant Evolution

First author: Shifeng Cheng; Affiliations: CAS Agricultural Genomics Institute at Shenzhen (中科院深圳农业基因组研究所): Shenzhen, China

Corresponding author: Michael Melkonian

The transition to a terrestrial environment, termed terrestrialization, is generally regarded as a pivotal event in the evolution and diversification of the land plant flora that changed the surface of our planet. Through phylogenomic studies, a group of streptophyte algae, the Zygnematophyceae, have recently been recognized as the likely sister group to land plants (embryophytes). Here, we report genome sequences and 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) that increase 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 Zygnematophyceae genomes represent a cornerstone for future studies to understand the underlying molecular mechanism and process of plant terrestrialization.

适应陆地环境的转变叫做陆地化，被认为是陆地植物演化和多样化的一次重要事件，同时也改变了我们星球的外貌。通过系统发育基因组学研究，一类链型藻类双星藻纲Zygnematophyceae最近被认为是陆地植物，即有胚植物的姊妹类群。本文中，作者报道了两个早期分化出来的双星藻纲植物和Spirogloea muscicola的Mesotaenium endlicherianum基因组，这些藻类植物与最早期分化的有胚植物，即苔藓植物享有共同的陆地生境。作者的研究表明双星藻纲植物和有胚植物共同的祖先通过来自土壤细菌的水平基因转移获得的GRAS和PYR/PYL/RCAR等基因增加了陆地植物的生物和非生物胁迫抗性。因此，这两个双星藻纲植物的基因组为将来有关植物陆地化的分子机制和进程等研究奠定了基石。

通讯：Martin Bayer (http://www.melkonian.uni-koeln.de/people_melkonian.html)

个人简介：1974年，汉堡大学，学士；1978年，汉堡大学，博士。

研究方向：微藻的结构、功能、起源和演化。

doi: https://doi.org/10.1016/j.cell.2019.10.019

Journal: Cell

Published online: November 14, 2019