The microbial profile of a tissue necrosis affecting the Atlantic invasive coral Tubastraea tagusensis

Aline Aparecida Zanotti,Gustavo Bueno Gregoracci,Marcelo Visentini Kitahara

doi:10.1038/s41598-021-89296-z

Aline Aparecida Zanotti, Gustavo Bueno Gregoracci + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-89296-z

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Abstract

The Southwestern Atlantic rocky reef ecosystems are undergoing significant changes due to sun-corals (Tubastraea tagusensis and T. coccinea) invasion. At Búzios Island, on the northern coast of São Paulo State, where the abundance of T. tagusensis is particularly high, some colonies are displaying tissue necrosis, a phenomenon never reported for this invasive nor any other azooxanthellate coral species. Using next-generation sequencing, we sought to understand the relationship between T. tagusensis tissue necrosis and its microbiota. Thus, through amplicon sequencing, we studied both healthy and diseased coral colonies. Results indicate a wide variety of bacteria associated with healthy colonies and an even higher diversity associated with those corals presenting tissue necrosis, which displayed nearly 25% more microorganisms. Also, as the microbial community associated with the seven healthy colonies did not alter composition significantly, it was possible to verify the microbial succession during different stages of tissue necrosis (i.e., initial, intermediate, and advanced). Comparing the microbiome from healthy corals to those in early tissue necrosis suggests 21 potential pathogens, which might act as the promoters of such disease.

Highlights

The Southwestern Atlantic rocky reef ecosystems are undergoing significant changes due to suncorals (Tubastraea tagusensis and T. coccinea) invasion
In Brazilian waters, analyses of the microbial community have been performed on the endemic corals Mussismilia braziliensis[7,25] and Mussismilia hispida[26,27], as well as in other more widely spread species, such as Madracis decactis[26,28], Siderastrea stellata[29], and on the invasive corals Tubastraea coccinea[26] and T. tagusensis[30]
Tubastraea tagusensis tissue necrosis generally starts at the tissue from the calicular margin like a small brown dot (Fig. 1A, B) that later expands through the polyp (Fig. 1C), sometimes leading to the death of several polyps (Fig. 1D)

Summary

Introduction

The Southwestern Atlantic rocky reef ecosystems are undergoing significant changes due to suncorals (Tubastraea tagusensis and T. coccinea) invasion. In Brazilian waters, analyses of the microbial community have been performed on the endemic corals Mussismilia braziliensis[7,25] and Mussismilia hispida[26,27], as well as in other more widely spread species, such as Madracis decactis[26,28], Siderastrea stellata[29], and on the invasive corals Tubastraea coccinea[26] and T. tagusensis[30] Some of these studies focused on the microbiota associated with healthy corals, but the microbial community associated with bleached and/or diseased colonies of M. braziliensis, S. stellata, and M. decactis were determined. This condition of T. tagusensis may be the downside of this invasive species because, in addition to having a high rate of clonality, it showed the absence of significant differences in the microbial community along a depth g radient[30]

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