Endosymbiont diversity and community structure in Porites lutea from Southeast Asia are driven by a suite of environmental variables

Abstract

Many corals depend upon the highly specialised and intricate relationship they form with Symbiodiniaceae algal symbionts. Porites lutea is a massive reef-building coral found throughout Southeast Asia that hosts these endosymbionts obligately. Yet despite the prevalence and importance of P. lutea as one of the most dominant corals here, its associated Symbiodiniaceae communities have not been precisely characterised. In this study, we used high-throughput DNA amplicon sequencing of the nuclear internal transcribed spacer 2 (ITS2) to characterise the diversity, community structure and biogeographic distribution of Symbiodiniaceae in P. lutea throughout Singapore and Peninsular Malaysia. Consistent with previous studies, we found that Cladocopium was the most dominant genus among all samples, and Cladocopium C15 was the most dominant type (or subclade) with 100% occurrence in all samples from every study site. Results also revealed numerous Symbiodiniaceae types associated with P. lutea that were previously undetected in Southeast Asia. Endosymbiont diversity and community variation are driven by a combination of site-specific mean monthly cloud cover and variance in monthly sea surface temperature. This study contributes baseline data toward understanding differences in Symbiodiniaceae assemblages hosted by P. lutea, shedding light on how they might be indicative of particular environmental conditions and coral responses.Electronic supplementary material The online version of this article (https://doi.

The Microbiome of the Reef Macroalga Sargassum ilicifolium in Singapore

“…We show that microbial communities are significantly different between locations despite the short distances separating them, and communities can be further differentiated dependent upon the structure sampled (e.g., leaf, vesicle or holdfast), with holdfasts appearing to have the most distinct community composition. These findings are in agreement with other work from the region that shows microbial community divergence at small spatial scales in a diverse range of marine taxa such as seagrasses [33], mangroves [32] and corals [60].…”

Spatial and Structural Factors Shape Seagrass-Associated Bacterial Communities in Singapore and Peninsular Malaysia

“…However, work is now challenging the notion that variance is low in microbial communities, and congruent with other research examining marine microbiomes (Cúcio et al, 2016;Crump et al, 2018;Bay et al, 2020;Osman et al, 2020;Tan et al, 2020;Wainwright et al, 2020) we show that bacterial communities can be significantly different between sampling location and structure examined, and this spatial variance is particularly strong in sediment samples in comparison to living seagrass structures. This is consistent with previously proposed hypotheses suggesting that habitats offered by living plant organs (i.e., leaf, fruit, etc.)…”

Host-symbiont coevolution, cryptic structure, and bleaching susceptibility, in a coral species complex (Scleractinia; Poritidae)

“…It also may be likely that bleaching susceptibility is associated with more fine-scale differences in symbiont community structure than was detected in this study. Although Cladocopium C15 is likely the dominant symbiont in this clade and was therefore used for reference mapping, Tan et al 48 found that a variety of other genera and subtypes of symbionts were associated with environmental gradients in Porites , as has been found by other studies as well as fine scale community shifts in the microbial community 48 – 50 . Although the coral host was the primary focus of this study, it is clear that for future work, the linkage between host and symbionts will be an important focal area to understand past diversification and future adaptation potential for these important reef building corals.…”