Comparison of Symbiodiniaceae diversities in different members of a Palythoa species complex (Cnidaria: Anthozoa: Zoantharia)-implications for ecological adaptations to different microhabitats

Masaru Mizuyama; Akira Iguchi; Mariko Iijima; Kodai Gibu; James Davis Reimer

doi:10.7717/peerj.8449

Comparison of Symbiodiniaceae diversities in different members of a Palythoa species complex (Cnidaria: Anthozoa: Zoantharia)-implications for ecological adaptations to different microhabitats

PeerJ. 2020 Feb 3:8:e8449. doi: 10.7717/peerj.8449. eCollection 2020.

Authors

Masaru Mizuyama^{1

2}, Akira Iguchi², Mariko Iijima², Kodai Gibu^{2

3}, James Davis Reimer^{1

4}

Affiliations

¹ Molecular Invertebrate Systematics and Ecology Laboratory, Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa, Japan.
² Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
³ Department of Bioresources Engineering, National Institute of Technology, Okinawa College, Nago, Okinawa, Japan.
⁴ Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Okinawa, Japan.

Abstract

In this study we compared genotypes of zoantharian host-associating algal symbionts among Palythoa species, which are among the dominant benthic reef organisms in the Ryukyu Archipelago, Japan, and evaluated Symbiodiniaceae diversities of closely related congeneric Palythoa species. We targeted a species complex of the zoantharian genus Palythoa (P. tuberculosa, P. sp. yoron, P. mutuki) living among different microhabitats in a narrow reef area of Tokunoshima Island. For phylogenetic analyses, we used two DNA marker regions; nuclear internal transcribed spacer (ITS) and plastid mini-circle non-coding region (psbA^ncr), both of which have previously been used to determine Symbiodiniaceae genotypes of zoantharian species. Our results showed that all Palythoa species hosted symbionts of the genus Cladocopium, with genotypic compositions of this genus showing some variations among the three different Palythoa species. Additionally, we found that the Cladocopium genotypic composition was statistically different among Palythoa species, and among P. tuberculosa specimens in different microhabitats. Our results suggest that ecological divergence among these three Palythoa species may be related to differing Symbiodiniaceae diversities that may in turn contribute to eco-physiological adaptation into different microhabitats on coral reefs.

Keywords: Ecological divergence; Palythoa species complex; Symbiodiniaceae; Zoantharia.

Grants and funding

This study was funded by the research support programs of the National Institute of Advanced Industrial Science and Technology to Masaru Mizuyama. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.