Zygnematophyceae are the algal sisters of land plants. Here we sequenced four genomes of filamentous Zygnematophyceae, including chromosome-scale assemblies for three strains of Zygnema circumcarinatum. We inferred traits in the ancestor of Zygnematophyceae and land plants that might have ushered in the conquest of land by plants: expanded genes for signaling cascades, environmental response, and multicellular growth. Zygnematophyceae and land plants share all the major enzymes for cell wall synthesis and remodifications, and gene gains shaped this toolkit. Co-expression network analyses uncover gene cohorts that unite environmental signaling with multicellular developmental programs. Our data shed light on a molecular chassis that balances environmental response and growth modulation across more than 600 million years of streptophyte evolution.

双藻纲是陆地植物的藻类姐妹。在这里，我们对丝状 Zygnematophyceae 的四个基因组进行了测序，包括Zygnemacircumcarinatum的三个菌株的染色体规模组装。我们推断出接合藻纲和陆地植物祖先的特征，这些特征可能导致植物征服陆地：信号级联、环境响应和多细胞生长的扩展基因。 Zygnematophyceae 和陆地植物共享细胞壁合成和修饰的所有主要酶，并且基因增益塑造了这个工具包。共表达网络分析揭示了将环境信号传导与多细胞发育程序结合起来的基因群。我们的数据揭示了链霉菌 6 亿多年进化过程中平衡环境响应和生长调节的分子底盘。