Stronger Together: Isograft Fusion Accelerates Recovery and May Facilitate Heat-Evolved Symbiont Transmission in Bleached Adult Corals.

Abstract

Experimentally evolved, heat-tolerant algal symbionts (heat-evolved; HE) offer a promising means of enhancing coral holobiont thermotolerance under warming oceans. However, translating their benefits into restoration practices requires scalable delivery methods. Coral tissue fusion may provide one such pathway by facilitating HE symbiont transfer to wild corals; however, its feasibility remains largely untested. As an initial test, we paired adult isografts of Galaxea fascicularis and Psammocora columna hosting HE Cladocopium proliferum (SS8) with chemically bleached, SS8-naive recipients. Fusion was first observed after 3 days in G. fascicularis and 9 days in P. columna. In both species, fu..