Advanced Science Research Center, Kanazawa University, Kanazawa 920-0934, Japan.
Graduate School of Science, Kobe University, Kobe 657-8501, Japan.
Cell. 2018 Jul 12;174(2):448-464.e24. doi: 10.1016/j.cell.2018.06.033.
Land plants evolved from charophytic algae, among which Charophyceae possess the most complex body plans. We present the genome of Chara braunii; comparison of the genome to those of land plants identified evolutionary novelties for plant terrestrialization and land plant heritage genes. C. braunii employs unique xylan synthases for cell wall biosynthesis, a phragmoplast (cell separation) mechanism similar to that of land plants, and many phytohormones. C. braunii plastids are controlled via land-plant-like retrograde signaling, and transcriptional regulation is more elaborate than in other algae. The morphological complexity of this organism may result from expanded gene families, with three cases of particular note: genes effecting tolerance to reactive oxygen species (ROS), LysM receptor-like kinases, and transcription factors (TFs). Transcriptomic analysis of sexual reproductive structures reveals intricate control by TFs, activity of the ROS gene network, and the ancestral use of plant-like storage and stress protection proteins in the zygote.
陆生植物由轮藻植物进化而来，其中石莼目具有最复杂的体型。我们呈现了小立碗藓的基因组；将基因组与陆生植物的基因组进行比较，确定了植物陆生化和陆生植物遗传基因的进化创新。小立碗藓利用独特的木聚糖合酶进行细胞壁生物合成，具有类似于陆生植物的胞质分裂（细胞分离）机制，以及许多植物激素。小立碗藓的质体通过类似于陆地植物的逆行信号进行控制，转录调控比其他藻类更为精细。该生物的形态复杂性可能源于基因家族的扩展，有三个特别值得注意的情况：影响对活性氧（ROS）耐受性的基因、LysM 受体样激酶和转录因子（TFs）。有性生殖结构的转录组分析揭示了 TF 的精细调控、ROS 基因网络的活性以及在合子中植物样储存和应激保护蛋白的古老用途。
