Changes in the transcriptome, ploidy, and optimal light intensity of a cryptomonad upon integration into a kleptoplastic dinoflagellate
Changes in the transcriptome, ploidy, and optimal light intensity of a cryptomonad upon integration into a kleptoplastic dinoflagellate
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DOI：
10.1038/s41396-020-0693-4
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发表时间：
2020-06-08
期刊：
影响因子：
11
通讯作者：
Miyagishima, Shin-ya
中科院分区：
文献类型：
--
作者：
Onuma, Ryo;Hirooka, Shunsuke;Miyagishima, Shin-ya
单细胞真核藻类与非光合真核生物的内共生已经在几个真核生物谱系中建立了叶绿体。此外，在几种不同的谱系中，某些单细胞生物会摄取藻类，并在消化藻类之前将其用作时间叶绿体（kleptoplasts）数周至数月。在这些生物中，dinoflagellateNusuttodinium aeruginodi吞噬隐单胞菌和染色体。在隐生殖腺核的帮助下扩大了窃听器。为了了解隐孢子虫细胞核是如何在鞭毛虫中重塑的，我们研究了摄入细胞核的转录组和倍性的变化。我们发现，摄入后，参与代谢、翻译和DNA复制的基因被上调，而参与感觉系统和细胞运动的基因被下调。在鞭毛细胞中，隐单胞核经历多倍体化，这与上调基因mRNA水平的增加有关。此外，摄取的细胞核几乎失去了对光的转录反应。由于已知多倍体化和转录调控缺失也发生在内共生细胞器的建立过程中，这些变化可能是内共生进化的共同趋势。此外，我们表明，盗贼和鞭毛虫比自由生活的隐单胞虫更容易受到强光的影响，但摄入的细胞核减少了这种损害。
Endosymbiosis of unicellular eukaryotic algae into previously nonphotosynthetic eukaryotes has established chloroplasts in several eukaryotic lineages. In addition, certain unicellular organisms in several different lineages ingest algae and utilize them as temporal chloroplasts (kleptoplasts) for weeks to months before digesting them. Among these organisms, the dinoflagellateNusuttodinium aeruginosumingests the cryptomonadChroomonassp. and enlarges the kleptoplast with the aid of the cryptomonad nucleus. To understand how the cryptomonad nucleus is remodeled in the dinoflagellate, here we examined changes in the transcriptome and ploidy of the ingested nucleus. We show that, after ingestion, genes involved in metabolism, translation, and DNA replication are upregulated while those involved in sensory systems and cell motility are downregulated. In the dinoflagellate cell, the cryptomonad nucleus undergoes polyploidization that correlates with an increase in the mRNA levels of upregulated genes. In addition, the ingested nucleus almost loses transcriptional responses to light. Because polyploidization and loss of transcriptional regulation are also known to have occurred during the establishment of endosymbiotic organelles, these changes are probably a common trend in endosymbiotic evolution. Furthermore, we show that the kleptoplast and dinoflagellate are more susceptible to high light than the free-living cryptomonad but that the ingested nucleus reduces this damage.