Hornworts comprise a bryophyte lineage that diverged from other extant land plants >400 million years ago and bears unique biological features, including a distinct sporophyte architecture, cyanobacterial symbiosis and a pyrenoid-based carbon-concentrating mechanism (CCM). Here, we provide three high-quality genomes of Anthoceros hornworts. Phylogenomic analyses place hornworts as a sister clade to liverworts plus mosses with high support. The Anthoceros genomes lack repeat-dense centromeres as well as whole-genome duplication, and contain a limited transcription factor repertoire. Several genes involved in angiosperm meristem and stomatal function are conserved in Anthoceros and upregulated during sporophyte development, suggesting possible homologies at the genetic level. We identified candidate genes involved in cyanobacterial symbiosis and found that LCIB, a Chlamydomonas CCM gene, is present in hornworts but absent in other plant lineages, implying a possible conserved role in CCM function. We anticipate that these hornwort genomes will serve as essential references for future hornwort research and comparative studies across land plants.

Hornworts 包含一个苔藓植物谱系，它与 4 亿年前其他现存的陆地植物不同，并具有独特的生物学特征，包括独特的孢子体结构、蓝藻共生和基于核糖体的碳浓缩机制 (CCM)。在这里，我们提供了三个高质量的Anthoceros hornworts 基因组。系统基因组分析将金银花作为地钱和苔藓的姐妹进化枝，具有很高的支持度。Anthoceros基因组缺乏重复密集的着丝粒以及全基因组重复，并且包含有限的转录因子库。与被子植物分生组织和气孔功能有关的几个基因在Anthoceros中是保守的并在孢子体发育过程中上调，表明在遗传水平上可能存在同源性。我们确定了参与蓝藻共生的候选基因，并发现LCIB是衣藻CCM 基因，存在于金鱼草中，但在其他植物谱系中不存在，这意味着在 CCM 功能中可能具有保守作用。我们预计这些金鱼草基因组将作为未来金鱼草研究和陆地植物比较研究的重要参考。