Groningen Institute of Evolutionary Life Sciences (GELIFES), University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands.
Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium.
Nature. 2016 Feb 18;530(7590):331-5. doi: 10.1038/nature16548. Epub 2016 Jan 27.
Seagrasses colonized the sea on at least three independent occasions to form the basis of one of the most productive and widespread coastal ecosystems on the planet. Here we report the genome of Zostera marina (L.), the first, to our knowledge, marine angiosperm to be fully sequenced. This reveals unique insights into the genomic losses and gains involved in achieving the structural and physiological adaptations required for its marine lifestyle, arguably the most severe habitat shift ever accomplished by flowering plants. Key angiosperm innovations that were lost include the entire repertoire of stomatal genes, genes involved in the synthesis of terpenoids and ethylene signalling, and genes for ultraviolet protection and phytochromes for far-red sensing. Seagrasses have also regained functions enabling them to adjust to full salinity. Their cell walls contain all of the polysaccharides typical of land plants, but also contain polyanionic, low-methylated pectins and sulfated galactans, a feature shared with the cell walls of all macroalgae and that is important for ion homoeostasis, nutrient uptake and O2/CO2 exchange through leaf epidermal cells. The Z. marina genome resource will markedly advance a wide range of functional ecological studies from adaptation of marine ecosystems under climate warming, to unravelling the mechanisms of osmoregulation under high salinities that may further inform our understanding of the evolution of salt tolerance in crop plants.
海草至少在三个独立的时期殖民海洋，形成了地球上最具生产力和广泛分布的沿海生态系统之一。在这里，我们报告了第一个海洋被子植物的基因组——Zostera marina（L.）。这为我们提供了独特的见解，了解了实现海洋生活方式所需的结构和生理适应所涉及的基因组的丧失和获得，这可以说是开花植物完成的最严峻的栖息地转变。关键的被子植物创新失去了包括气孔基因、参与萜类化合物和乙烯信号转导的基因，以及用于紫外线保护和远红感应的光敏色素的整个基因库。海草还恢复了使其适应高盐度的功能。它们的细胞壁包含陆地植物特有的所有多糖，但也含有带负电荷、低甲基化的果胶和硫酸半乳糖，这一特征与所有大型藻类的细胞壁共享，对于离子稳态、养分吸收和通过叶表皮细胞进行 O2/CO2 交换非常重要。Z. marina 基因组资源将极大地推动广泛的功能生态研究，从适应气候变暖下的海洋生态系统，到揭示高盐度下渗透调节的机制，这可能进一步加深我们对作物耐盐性进化的理解。
