Metacommunity ecology of Symbiodiniaceae hosted by the coral Galaxea fascicularis
Metacommunity ecology of Symbiodiniaceae hosted by the coral Galaxea fascicularis
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DOI：
10.3354/meps13177
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发表时间：
2020-01
影响因子：
2.5
通讯作者：
Patricia H. Wepfer;Yuichi Nakajima;Fkc Hui;S. Mitarai;E.P. Economo
中科院分区：
文献类型：
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作者：
Patricia H. Wepfer;Yuichi Nakajima;Fkc Hui;S. Mitarai;E.P. Economo
珊瑚藻共生代表了珊瑚礁生态系统的营养和结构基础。然而，尽管珊瑚礁面临全球性威胁，珊瑚健康和抗逆性也依赖于这种互利共生，但人们对内共生共生科的群落生态知之甚少。元群落生态学的概念和方法可以用来帮助我们理解共生群落的组装和稳定性以及它们所包含的互利共生。在这项研究中，我们对日本西南部的共生体珊瑚 Galaxea fasciculis 的菌落进行了采样，评估了环境和宿主因素对 Symbiodinia ceae 群落组成的影响，同时探索了共生体类型之间的残余相关性，这些相关性可能反映了物种相互作用等非随机组装过程。我们对共生科核糖体内转录间隔区 2 (ITS2) 区域进行了元条形码编码，并使用 2 个不同的 OTU 身份截止点来表征内共生群落，并使用广义相异性模型和联合物种分布模型对其进行了分析。我们发现共生科形成离散的群落，其特征是 ITS2 类型 C1、C21a 或 D1 占主导地位，它们各自与一组不同的共生背景类型相关，并且倾向于在内共生群落中相互排斥。这些群落对温度、水深、宿主基因型、息肉大小和漂白状态表现出适度的反应，并且 ITS2 类型内存在局部序列变异。在考虑了这些变量的影响后，群落组成中仍然存在剩余相关性，这表明珊瑚中的共生科群落组装可能是通过种间竞争或促进相互作用而不仅仅是外源变量来构建的。
Coral−algae symbiosis represents the trophic and structural basis of coral reef ecosystems. However, despite global threats to coral reefs and the dependence of coral health and stress resistance upon such mutualisms, little is known about the community ecology of endosymbiotic Symbiodiniaceae. Concepts and methods from metacommunity ecology may be used to help us understand the assembly and stability of symbiont communities and the mutualisms they comprise. In this study, we sampled colonies of the symbiont-generalist coral Galaxea fascicularis in southwestern Japan and assessed the effects of environmental and host factors on Symbiodinia ceae community composition, while simultaneously exploring residual correlations among symbiont types that may reflect non-random assembly processes such as species interactions. We metabarcoded the Symbiodiniaceae ribosomal internal transcribed spacer 2 (ITS2) region and characterized the endosymbiotic community using 2 different OTU identity cut-offs, and analyzed them with generalized dissimilarity modeling and joint species distribution modeling. We found that Symbiodiniaceae form discrete communities characterized by the dominance of ITS2 types C1, C21a, or D1, that are each associated with a different suite of co-occurring background types and tend to exclude each other in an endosymbiotic community. The communities showed modest responses to temperature, water depth, host genotype, polyp size, and bleaching status, and there was local sequence variation within the ITS2 types. After accounting for the effects of those variables, residual correlations remained in community composition, pointing to the possibility that Symbiodiniaceae community assembly in corals may be structured by interspecific competitive or facilitating interactions rather than only exogenous variables.