Thermal and Herbicide Tolerances of Chromerid Algae and Their Ability to Form a Symbiosis With Corals
Thermal and Herbicide Tolerances of Chromerid Algae and Their Ability to Form a Symbiosis With Corals
复制标题
DOI：
10.3389/fmicb.2019.00173
复制
发表时间：
2019-02-12
影响因子：
5.2
通讯作者：
van Oppen, Madeleine J. H.
中科院分区：
文献类型：
--
作者：
Chakravarti, Leela J.;Negri, Andrew P.;van Oppen, Madeleine J. H.
造礁珊瑚与共生藻科中的光合微藻形成专性共生关系，以满足其大部分能量需求。这种共生关系正受到前所未有的海洋变暖速度的威胁，同时也受到水质差等当地压力因素的压力。大堡礁（GBR）的夏季平均海面温度（SST）仅高出1摄氏度就可以引发共生藻科从宿主中消失，而最常见的除草剂敌草隆（diuron）的浓度非常低，可以破坏微藻的光合作用活性。在环境迅速变化的时代，正在对珊瑚全生物的辅助进化进行调查，以提高珊瑚的适应能力。2008年发现了类似顶复门的微藻，并创建了Chromerida门（Chromerids）。已从珊瑚中分离出染色质，并含有功能性光合质体。因此，他们的发现开辟了一条新的研究途径，利用珊瑚的替代/额外的光合共生体。然而，迄今为止只有两项研究调查了Chromera velia与珊瑚的共生性质，因此对珊瑚与Chromerid的关系知之甚少。此外，chromerids对环境压力的反应还没有被研究。在这里，我们测试了四个chromerid菌株和常见的甲藻共生体Cladocopia goreaui（以前的Symbiodinium goreaui，ITS 2 C1型）在高温，敌草隆和它们的组合暴露的性能。四个chromerid菌株中的三个表现出高的耐热性，两个菌株表现出特殊的除草剂耐受性，大于任何光合微藻，包括C。goreaui。我们还调查了发病的chromerids和两个常见的GBR珊瑚物种的幼虫之间的共生环境和应力条件下。与C. goreaui。与C相比，我们没有观察到接种Chromerid algae对幼虫适合度的任何总体负面或正面影响。goreaui。然而，我们不能排除的可能性，chromerid藻类可能有更重要的作用，在以后的珊瑚生命阶段，并建议这是未来的研究重点。
Reef-building corals form an obligate symbiosis with photosynthetic microalgae in the family Symbiodiniaceae that meet most of their energy requirements. This symbiosis is under threat from the unprecedented rate of ocean warming as well as the simultaneous pressure of local stressors such as poor water quality. Only 1 degrees C above mean summer sea surface temperatures (SSTs) on the Great Barrier Reef (GBR) can trigger the loss of Symbiodiniaceae from the host, and very low concentrations of the most common herbicide, diuron, can disrupt the photosynthetic activity of microalgae. In an era of rapid environmental change, investigation into the assisted evolution of the coral holobiont is underway in an effort to enhance the resilience of corals. Apicomplexan-like microalgae were discovered in 2008 and the Phylum Chromerida (chromerids) was created. Chromerids have been isolated from corals and contain a functional photosynthetic plastid. Their discovery therefore opens a new avenue of research into the use of alternative/additional photosymbionts of corals. However, only two studies to-date have investigated the symbiotic nature of Chromera velia with corals and thus little is known about the coral-chromerid relationship. Furthermore, the response of chromerids to environmental stressors has not been examined. Here we tested the performance of four chromerid strains and the common dinofiagellate symbiont Cladocopium goreaui (formerly Symbiodinium goreaui, ITS2 type C1) in response to elevated temperature, diuron and their combined exposure. Three of the four chromerid strains exhibited high thermal tolerances and two strains showed exceptional herbicide tolerances, greater than observed for any photosynthetic microalgae, including C. goreaui. We also investigated the onset of symbiosis between the chromerids and larvae of two common GBR coral species under ambient and stress conditions. Levels of colonization of coral larvae with the chromerid strains were low compared to colonization with C. goreaui. We did not observe any overall negative or positive larval fitness effects of the inoculation with chromerid algae vs. C. goreaui. However, we cannot exclude the possibility that chromerid algae may have more important roles in later coral life stages and recommend this be the focus of future studies.