Kim Jong Im, Jeong Minseok, Archibald John M, Shin Woongghi
Department of Biology, Chungnam National University, Daejeon, South Korea.
Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada.
Front Plant Sci. 2020 Sep 10;11:572703. doi: 10.3389/fpls.2020.572703. eCollection 2020.
-like heterotrophic chrysophytes are important eukaryotic microorganisms that feed on bacteria in aquatic and soil environments. They are characterized by their lack of pigmentation, naked cell surface, and extremely small size. Although -like chrysophytes have lost their photosynthetic ability, they still possess a leucoplast and retain a plastid genome. We have sequenced the plastid genomes of three non-photosynthetic chrysophytes, sp. Baeckdong012018B8, sp. Jangsampo120217C5 and Yongseonkyo072317C3, and compared them to the previously sequenced plastid genome of "" sp. NIES-1846 and photosynthetic chrysophytes. We found the plastid genomes of -like flagellates to be generally conserved with respect to genome structure and housekeeping gene content. We nevertheless also observed lineage-specific gene rearrangements and duplication of partial gene fragments at the boundary of the inverted repeat and single copy regions. Most gene losses correspond to genes for proteins involved in photosynthesis and carbon fixation, except in the case of F. The newly sequenced plastid genomes range from ~55.7 kbp to ~62.9 kbp in size and share a core set of 45 protein-coding genes, 3 rRNAs, and 32 to 34 tRNAs. Our results provide insight into the evolutionary history of organelle genomes genome reduction and gene loss related to loss of photosynthesis in chrysophyte evolution.
类似异养金藻的生物是重要的真核微生物，它们在水生和土壤环境中以细菌为食。它们的特征是缺乏色素沉着、细胞表面裸露且体积极小。尽管类似金藻的生物已经失去了光合作用能力，但它们仍然拥有白色体并保留了质体基因组。我们对三种非光合金藻（Baeckdong012018B8 种、Jangsampo120217C5 种和 Yongseonkyo072317C3 种）的质体基因组进行了测序，并将它们与之前测序的“”种 NIES - 1846 的质体基因组以及光合金藻进行了比较。我们发现类似鞭毛虫的质体基因组在基因组结构和管家基因含量方面总体上是保守的。然而，我们也观察到了特定谱系的基因重排以及反向重复和单拷贝区域边界处部分基因片段的重复。除了 F 种的情况外，大多数基因丢失对应于参与光合作用和碳固定的蛋白质的基因。新测序的质体基因组大小在约 55.7 kbp 到约 62.9 kbp 之间，共有一组核心的 45 个蛋白质编码基因、3 个 rRNA 和 32 到 34 个 tRNA。我们的结果为细胞器基因组的进化历史、与金藻进化中光合作用丧失相关的基因组减少和基因丢失提供了见解。
