{"title":"Steroid markers for species-specific Symbiodiniaceae: insights from molecular and δ13C measurements on four scleractinian corals","authors":"Xiaowei Zhu, Fen Chen, Guodong Jia, Pingan Peng, Hui Huang, Xiyang Zhang, Wen Yan","doi":"10.1007/s00338-024-02492-x","DOIUrl":null,"url":null,"abstract":"<p>Endosymbiotic dinoflagellates in the family Symbiodiniaceae are physiologically and ecologically important for reef-building corals. Certain symbiotic lineages may provide adaptive functions that aid corals in coping with and surviving rapid environmental and climate changes; and thus, there is a growing interest in exploring Symbiodiniaceae communities and their associated roles. Steroid biomarkers have been proposed as a means of identifying species-specific symbionts, but their reliability has yet to be examined through comparison of different coral species that harbor known Symbiodiniaceae. Here, steroid molecular and <i>δ</i><sup>13</sup>C analyses are applied to four stony corals that host identified (<i>Porites lobata</i> and <i>Galaxea fascicularis</i>) or undescribed (<i>Goniopora tenuidens</i> and <i>Goniastrea minuta</i>) Symbiodiniaceae to address this issue. The 23-Me C<sub>28</sub>Δ<sup>5,22</sup>, 23,24-Me C<sub>29</sub>Δ<sup>5,22</sup>, and dinosterol are characteristic of <i>P. lobata</i>; while, C<sub>29</sub>Δ<sup>5</sup>, gorgosterol, and 4α-methylgorgostanol are diagnostic for <i>G. fascicularis</i>, tracking the marked differences in their Symbiodiniaceae assemblages. These two steroid groups also exhibit largely similar (− 20.6 to − 17.0‰) and visibly variable (− 24.1 to − 17.3‰) <i>δ</i><sup>13</sup>C signatures, following the low and high diversity of symbionts in <i>P. lobata</i> and <i>G. fascicularis</i>, respectively. Our present results, together with previous reports, clearly demonstrate the effectiveness of steroid molecular and <i>δ</i><sup>13</sup>C features in depicting Symbiodiniaceae population, providing a useful complement to Symbiodiniaceae genetic analysis. A further comparison of steroid characteristics between unclear and known Symbiodiniaceae in our four corals reveals the almost identical symbiotic population between <i>G. minuta</i> and <i>G. fascicularis</i> and a restricted range of symbiotic composition in <i>G. tenuidens</i> that is shared with <i>G. fascicularis</i> (and <i>G. minuta</i>). Additionally, the occurrence of 5α-stanols suggestive of anaerobic conversion on Δ<sup>5</sup>-sterols implies complex steroid interactions within coral–algae–microbe holobionts.</p>","PeriodicalId":10821,"journal":{"name":"Coral Reefs","volume":"52 1","pages":""},"PeriodicalIF":2.9000,"publicationDate":"2024-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Coral Reefs","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s00338-024-02492-x","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MARINE & FRESHWATER BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Endosymbiotic dinoflagellates in the family Symbiodiniaceae are physiologically and ecologically important for reef-building corals. Certain symbiotic lineages may provide adaptive functions that aid corals in coping with and surviving rapid environmental and climate changes; and thus, there is a growing interest in exploring Symbiodiniaceae communities and their associated roles. Steroid biomarkers have been proposed as a means of identifying species-specific symbionts, but their reliability has yet to be examined through comparison of different coral species that harbor known Symbiodiniaceae. Here, steroid molecular and δ13C analyses are applied to four stony corals that host identified (Porites lobata and Galaxea fascicularis) or undescribed (Goniopora tenuidens and Goniastrea minuta) Symbiodiniaceae to address this issue. The 23-Me C28Δ5,22, 23,24-Me C29Δ5,22, and dinosterol are characteristic of P. lobata; while, C29Δ5, gorgosterol, and 4α-methylgorgostanol are diagnostic for G. fascicularis, tracking the marked differences in their Symbiodiniaceae assemblages. These two steroid groups also exhibit largely similar (− 20.6 to − 17.0‰) and visibly variable (− 24.1 to − 17.3‰) δ13C signatures, following the low and high diversity of symbionts in P. lobata and G. fascicularis, respectively. Our present results, together with previous reports, clearly demonstrate the effectiveness of steroid molecular and δ13C features in depicting Symbiodiniaceae population, providing a useful complement to Symbiodiniaceae genetic analysis. A further comparison of steroid characteristics between unclear and known Symbiodiniaceae in our four corals reveals the almost identical symbiotic population between G. minuta and G. fascicularis and a restricted range of symbiotic composition in G. tenuidens that is shared with G. fascicularis (and G. minuta). Additionally, the occurrence of 5α-stanols suggestive of anaerobic conversion on Δ5-sterols implies complex steroid interactions within coral–algae–microbe holobionts.
期刊介绍:
Coral Reefs, the Journal of the International Coral Reef Society, presents multidisciplinary literature across the broad fields of reef studies, publishing analytical and theoretical papers on both modern and ancient reefs. These encourage the search for theories about reef structure and dynamics, and the use of experimentation, modeling, quantification and the applied sciences.
Coverage includes such subject areas as population dynamics; community ecology of reef organisms; energy and nutrient flows; biogeochemical cycles; physiology of calcification; reef responses to natural and anthropogenic influences; stress markers in reef organisms; behavioural ecology; sedimentology; diagenesis; reef structure and morphology; evolutionary ecology of the reef biota; palaeoceanography of coral reefs and coral islands; reef management and its underlying disciplines; molecular biology and genetics of coral; aetiology of disease in reef-related organisms; reef responses to global change, and more.