Jain Sudhanshi S, Afiq-Rosli Lutfi, Feldman Bar, Levy Oren, Phua Jun Wei, Wainwright Benjamin J, Huang Danwei
Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore.
Tropical Marine Science Institute, National University of Singapore, 18 Kent Ridge Road, Singapore 119227, Singapore.
Microorganisms. 2020 Sep 7;8(9):1370. doi: 10.3390/microorganisms8091370.
Thermal stress drives the bleaching of reef corals, during which the endosymbiotic relationship between Symbiodiniaceae microalgae and the host breaks down. The endosymbiont communities are known to shift in response to environmental disturbances, but how they respond within and between colonies during and following bleaching events remains unclear. In 2016, a major global-scale bleaching event hit countless tropical reefs. Here, we investigate the relative abundances of LaJeunesse & H.J.Jeong, 2018 and LaJeunesse, 2018 within and among colonies in equatorial Singapore that are known to host both these Symbiodiniaceae clades. Bleached and unbleached tissues from bleaching colonies, as well as healthy colonies, during and following the bleaching event were sampled and analyzed for comparison. The nuclear ribosomal internal transcribed spacer (ITS) regions were separately amplified and quantified using a SYBR Green-based quantitative polymerase chain reaction (qPCR) method and Illumina high-throughput sequencing. We found to be highly abundant relative to . The relative abundance of , known to be thermally tolerant, was highest in post-bleaching healthy colonies, while bleached and unbleached tissues from bleaching colonies as well as tissue from healthy colonies during the event had depressed proportions of . Given the importance of for thermal tolerance and stress response, it is surprising that bleached tissue showed limited change over healthy tissue during the bleaching event. Moreover, colonies were invariably dominated by during bleaching, but a minority of colonies were -dominant during non-bleaching times. The detailed characterization of Symbiodiniaceae in specific colonies during stress and recovery will provide insights into this crucial symbiosis, with implications for their responses during major bleaching events.
热应激导致珊瑚礁珊瑚白化，在此过程中，共生藻（Symbiodiniaceae）微藻与宿主之间的内共生关系瓦解。已知内共生体群落会因环境干扰而发生变化，但在白化事件期间及之后，它们在群体内部和群体之间如何响应仍不清楚。2016年，一场全球性的重大白化事件袭击了无数热带珊瑚礁。在此，我们调查了赤道新加坡已知同时拥有这两个共生藻分支的群体内部和群体之间2018年的拉热内斯（LaJeunesse）和郑（H.J.Jeong）的相对丰度。在白化事件期间及之后，对白化群体的白化和未白化组织以及健康群体进行采样和分析以作比较。使用基于SYBR Green的定量聚合酶链反应（qPCR）方法和Illumina高通量测序分别扩增和定量核糖体核糖核酸内转录间隔区（ITS）区域。我们发现相对于[具体名称未给出]，[具体名称未给出]的丰度极高。已知耐热的[具体名称未给出]的相对丰度在白化后健康群体中最高，而白化群体的白化和未白化组织以及事件期间健康群体的组织中[具体名称未给出]的比例较低。鉴于[具体名称未给出]对耐热性和应激反应的重要性，令人惊讶的是，在白化事件期间，白化组织与健康组织相比变化有限。此外，群体在白化期间总是以[具体名称未给出]为主，但少数群体在非白化时期以[具体名称未给出]为主。在应激和恢复期间对特定群体中的共生藻进行详细表征将为这种关键的共生关系提供见解，这对它们在重大白化事件中的反应具有启示意义。
