Insights into the red algae and eukaryotic evolution from the genome of Porphyra umbilicalis (Bangiophyceae, Rhodophyta)
Insights into the red algae and eukaryotic evolution from the genome of Porphyra umbilicalis (Bangiophyceae, Rhodophyta)
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DOI：
10.1073/pnas.1703088114
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发表时间：
2017-08-01
影响因子：
11.1
通讯作者：
Prochnik, Simon E.
中科院分区：
文献类型：
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作者：
Brawley, Susan H.;Blouin, Nicolas A.;Prochnik, Simon E.
脐紫菜属于古老的红藻类群（Bangiophyceae），为人类食物而收获，并在潮间带上游的恶劣条件下繁衍生息。在这里，我们展示了 87.7-Mbp 单倍体紫菜基因组（65.8% G + C 含量，13,125 个基因位点），并阐明了有助于我们理解红藻作为少数多细胞真核谱系之一的生物学特性的特征。紫菜基因组与其他红藻共有的新特征涉及细胞骨架、钙信号、细胞周期和包括光保护在内的应激耐受机制。紫菜中的细胞骨架马达蛋白仅限于一小部分驱动蛋白，它们似乎是红藻中唯一通用的细胞骨架马达。动力蛋白马达不存在，大多数红藻（包括紫菜）缺乏肌球蛋白。这种令人惊讶的最小细胞骨架为为什么红藻细胞和多细胞结构的大小比大多数多细胞谱系更有限提供了可能的解释。与管藻植物的胁迫耐受性进一步相关的其他发现包括用于亲水性富含半乳聚糖的细胞壁硫酸化的祖先酶、起源于绿藻和红藻分化之前的甘露聚糖合成的证据，以及高营养吸收能力。我们的分析提供了对红藻的全面了解，红藻不仅具有重要的商业价值，而且通过次生内共生在其他藻类的进化中发挥了重要作用。
Porphyra umbilicalis (laver) belongs to an ancient group of red algae (Bangiophyceae), is harvested for human food, and thrives in the harsh conditions of the upper intertidal zone. Here we present the 87.7-Mbp haploid Porphyra genome (65.8% G + C content, 13,125 gene loci) and elucidate traits that inform our understanding of the biology of red algae as one of the few multicellular eukaryotic lineages. Novel features of the Porphyra genome shared by other red algae relate to the cytoskeleton, calcium signaling, the cell cycle, and stress-tolerance mechanisms including photoprotection. Cytoskeletal motor proteins in Porphyra are restricted to a small set of kinesins that appear to be the only universal cytoskeletal motors within the red algae. Dynein motors are absent, and most red algae, including Porphyra, lack myosin. This surprisingly minimal cytoskeleton offers a potential explanation for why red algal cells and multicellular structures are more limited in size than in most multicellular lineages. Additional discoveries further relating to the stress tolerance of bangiophytes include ancestral enzymes for sulfation of the hydrophilic galactan-rich cell wall, evidence for mannan synthesis that originated before the divergence of green and red algae, and a high capacity for nutrient uptake. Our analyses provide a comprehensive understanding of the red algae, which are both commercially important and have played a major role in the evolution of other algal groups through secondary endosymbioses.