Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan.
Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan.
DNA Res. 2023 Aug 1;30(4). doi: 10.1093/dnares/dsad014.
Vestimentiferan tubeworms are representative members of deep-sea chemosynthetic ecosystems. In this study, we developed a draft genome and gene models and performed genomic and transcriptomic analyses of Lamellibrachia satsuma, the only vestimentiferan reported from the euphotic zone. The quality of the genome assembly and gene models is comparable to or higher than those of previously reported vestimentiferan tubeworms. Tissue-specific transcriptome sequencing revealed that Toll-like receptor genes and lineage-specific expanded bacteriolytic enzyme genes are highly expressed in the obturacular and vestimental regions, respectively, suggesting the importance of these tissues in defense against pathogens. On the other hand, globin subunit genes are expressed almost exclusively in the trunk region, supporting the hypothesis that the trophosome is the site of haemoglobin biosynthesis. Vestimentiferan-specific expanded gene families included chitinases, ion channels, and C-type lectins, suggesting the importance of these functions for vestimentiferans. C-type lectins in the trunk region, in particular, may be involved in recognition of pathogens, or in interactions between tubeworms and symbiotic bacteria. Our genomic and transcriptomic analyses enhance understanding of molecular mechanisms underlying the unique lifestyle of vestimentiferan tubeworms, particularly their obligate mutualism with chemosynthetic bacteria.
管栖蠕虫是深海化能合成生态系统的代表性成员。在这项研究中，我们对来自透光带的唯一一种管栖蠕虫——鳞沙蚕（Lamellibrachia satsuma），进行了基因组草图和基因模型的构建，并开展了基因组和转录组分析。基因组组装和基因模型的质量与先前报道的管栖蠕虫相当或更高。组织特异性转录组测序表明，Toll 样受体基因和谱系特异性扩展的细菌裂解酶基因分别在闭锁器和护套区域高度表达，表明这些组织在抵御病原体方面的重要性。另一方面，珠蛋白亚基基因几乎只在躯干部表达，支持了营养体是血红蛋白生物合成部位的假说。管栖蠕虫特有的扩展基因家族包括几丁质酶、离子通道和 C 型凝集素，表明这些功能对管栖蠕虫很重要。特别是躯干部的 C 型凝集素，可能参与对病原体的识别，或管栖蠕虫与共生细菌之间的相互作用。我们的基因组和转录组分析增强了对管栖蠕虫独特生活方式的分子机制的理解，特别是它们与化能合成细菌的专性共生关系。
