背景回顾：The large size and complexity of most fern genomes have hampered efforts to elucidate fundamental aspects of fern biology and land plant evolution through genome-enabled research. 

主要研究：Here we present a chromosomal genome assembly and associated methylome, transcriptome and metabolome analyses for the model fern species Ceratopteris richardii. 

结果1-基因组演化：The assembly reveals a history of remarkably dynamic genome evolutionincluding rapid changes in genome content and structure following the most recent whole-genome duplication approximately 60 million years ago. These changes include massive gene loss, rampant tandem duplications and multiple horizontal gene transfers from bacteria, contributing to the diversification of defence-related gene families.  

结果2-基因组大和基因长：The insertion of transposable elements into introns has led to the large size of the Ceratopteris genome and to exceptionally long genes relative to other plants. 

结果3-种子发育基因演化：Gene family analyses indicate that genes directing seed developmentwere co-opted from those controlling the development of fern sporangia, providing insights into seed plant evolution. 

结论：Our findings and annotated genome assembly extend the utility of Ceratopteris as a model for investigating and teaching plant biology.

 摘 要 

大多数蕨类植物的基因组都比较大且复杂，因此阻碍了通过基因组学方法来进行蕨类植物生物学和陆地植物演化相关的研究。本文中，作者报道了模式蕨类植物水蕨（Ceratopteris richardii）的染色体基因组以及相关的甲基化组、转录组和代谢组。水蕨基因组揭示了蕨类植物基因组剧烈的动态基因组演化历史，包括紧随6千万年前发生的全基因复制事件后的基因组组分和结构快速变化。这些变化包括了大量的基因丢失、普遍的串联重复以及许多来自细菌的水平基因转移，共同作用于防御相关基因家族的多样化。内含子中转座子的插入导致了水蕨基因组较大，并且导致了其基因长度比其他陆地植物要长。基因家族分析显示，指导种子发育的基因是从控制蕨类孢子囊发育的基因中演化而来，这为种子植物的演化提供了见解。本文的研究结果拓宽了蕨类植物可利用的基因组，为进一步的蕨类植物生物学研究提供了遗传资源。

** Zhong-Hua Chen **