Cell Cycle Dynamics of Cultured Coral Endosymbiotic Microalgae (Symbiodinium) Across Different Types (Species) Under Alternate Light and Temperature Conditions
Cell Cycle Dynamics of Cultured Coral Endosymbiotic Microalgae (Symbiodinium) Across Different Types (Species) Under Alternate Light and Temperature Conditions
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DOI：
10.1111/jeu.12497
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发表时间：
2018-07-01
影响因子：
2.2
通讯作者：
Suggett, David J.
中科院分区：
文献类型：
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作者：
Fujise, Lisa;Nitschke, Matthew R.;Suggett, David J.
共生藻属的甲藻与许多无脊椎动物共生，包括造礁珊瑚。宿主通过驱逐和降解（有丝分裂后）持续调节共生藻细胞密度和/或通过操纵共生细胞周期（有丝分裂前）限制细胞生长和分裂来维持这种共生。有丝分裂前调控的重要性尚不清楚，因为有关共生藻巨大遗传多样性的细胞周期的数据很少。因此，我们检查了几种不同 SymbiodiniumITS2 类型（B1、C1、D1a）的细胞周期进程。所有类型均表现出典型的微藻细胞周期进程，在光照期间从G(1)期到S期，在黑暗期从S期到G(2)/M期。然而，菌株之间处于这些阶段的细胞比例不同，反映了生长速率的差异。观察到具有 3n DNA 含量的未分裂的较大细胞，尤其是在 D1a 型中，其表现出独特的细胞周期模式。我们进一步比较了不同生长光强度和热状态下的细胞周期模式。虽然光强度不影响细胞周期模式，但热应激抑制细胞周期进展并使所有菌株停滞在 G(1) 期。我们讨论了了解共生藻功能多样性的重要性，以及我们的研究结果如何应用于阐明宿主-共生藻共生的稳定性。
Dinoflagellates of the genus Symbiodinium live in symbiosis with many invertebrates, including reef-building corals. Hosts maintain this symbiosis through continuous regulation of Symbiodinium cell density via expulsion and degradation (postmitotic) and/or constraining cell growth and division through manipulation of the symbiont cell cycle (premitotic). Importance of premitotic regulation is unknown since little data exists on cell cycles for the immense genetic diversity of Symbiodinium. We therefore examined cell cycle progression for several distinct SymbiodiniumITS2-types (B1, C1, D1a). All types exhibited typical microalgal cell cycle progression, G(1) phase through to S phase during the light period, and S phase to G(2)/M phase during the dark period. However, the proportion of cells in these phases differed between strains and reflected differences in growth rates. Undivided larger cells with 3n DNA content were observed especially in type D1a, which exhibited a distinct cell cycle pattern. We further compared cell cycle patterns under different growth light intensities and thermal regimes. Whilst light intensity did not affect cell cycle patterns, heat stress inhibited cell cycle progression and arrested all strains in G(1) phase. We discuss the importance of understanding Symbiodinium functional diversity and how our findings apply to clarify stability of host-Symbiodinium symbioses.