The use of experimentally evolved coral photosymbionts for reef restoration

• Published in: Trends in microbiology (Regular ed.) 2024-12, Vol.32 (12), p.1241-1252
• Main Authors: Nitschke, Matthew R., Abrego, David, Allen, Corinne E., Alvarez-Roa, Carlos, Boulotte, Nadine M., Buerger, Patrick, Chan, Wing Yan, Fae Neto, Wladimir A., Ivory, Elizabeth, Johnston, Bede, Meyers, Luka, Parra V, Catalina, Peplow, Lesa, Perez, Tahirih, Scharfenstein, Hugo J., van Oppen, Madeleine J.H.
• Format: Article
• Language: English
• Subjects: adaptation; Animals; Anthozoa - microbiology; Anthozoa - physiology; biodiversity; Coral Reefs; Dinoflagellida - physiology; Hot Temperature; industry; intervention; microalgae; selection; stakeholder engagement; Symbiosis
• ISSN: 0966-842X; 1878-4380; 1878-4380
• DOI: 10.1016/j.tim.2024.05.008

The heat tolerance of corals is largely determined by their microbial photosymbionts, and manipulating these symbiont communities may enhance the ability of corals to survive summer heatwaves.Experimental evolution of Symbiodiniaceae cultures under elevated temperatures has been successfully used to enhance the upper thermal tolerance of both symbiont cultures in vitro and corals following inoculation.Novel culturing, upscaling, and biodiversity monitoring techniques are required to deliver experimentally evolved coral symbionts at scale, and success requires learning from, or directly utilising, adjacent industries (e.g., biotechnology for algae-based commodities).This intervention has transitioned from stakeholder engagement to regulatory approval for risk assessments via small-scale field trials, which is an essential step on the path to implementation. The heat tolerance of corals is largely determined by their microbial photosymbionts (Symbiodiniaceae, colloquially known as zooxanthellae). Therefore, manipulating symbiont communities may enhance the ability of corals to survive summer heatwaves. Although heat-tolerant and -sensitive symbiont species occur in nature, even corals that harbour naturally tolerant symbionts have been observed to bleach during summer heatwaves. Experimental evolution (i.e., laboratory selection) of Symbiodiniaceae cultures under elevated temperatures has been successfully used to enhance their upper thermal tolerance, both in vitro and, in some instances, following their reintroduction into corals. In this review, we present the state of this intervention and its potential role within coral reef restoration, and discuss the next critical steps required to bridge the gap to implementation. The heat tolerance of corals is largely determined by their microbial photosymbionts (Symbiodiniaceae, colloquially known as zooxanthellae). Therefore, manipulating symbiont communities may enhance the ability of corals to survive summer heatwaves. Although heat-tolerant and -sensitive symbiont species occur in nature, even corals that harbour naturally tolerant symbionts have been observed to bleach during summer heatwaves. Experimental evolution (i.e., laboratory selection) of Symbiodiniaceae cultures under elevated temperatures has been successfully used to enhance their upper thermal tolerance, both in vitro and, in some instances, following their reintroduction into corals. In this review, we present the state of this intervention and