Meeting Abstract

P1-111   -   Fitness benefits in coral juveniles through transgenerational inheritance of shuffled symbiont communities in the coral Montipora digitata Olivares-Zambrano , D*; Timmons, C; Kenkel , CD ; Quigley, KM ; University of Southern California, Los Angeles ; Australian Institute of Marine Science, Townsville ; James Cook University, Townsville danielo7@usc.edu

Coral reefs worldwide are threatened by increasing ocean temperatures. About 25% of reef building corals form obligate, mutualistic symbiotic relationships with dinoflagellates in the family Symbiodiniaceae by acquiring symbionts predominantly from their parents through (vertical transmission). Symbiodiniaceae vary in their thermal tolerance thresholds, in which a coral’s ability to tolerate thermal stress is significantly influenced by the tolerance of their endosymbiotic community. Corals may tolerate a wider range of temperatures through an alteration in the density relative abundance of symbiont types, termed shuffling, where alterations can be transgenerationally inherited. Larvae and juveniles of the vertically transmitting coral Montipora digitata were subjected to heat stress (32°C) and their symbiont communities pre- and post-stress were characterized using amplicon sequencing of the ITS2-rDNA region, as well as survival and, size of larvae and juveniles, and photosynthetic efficiency of the symbionts. Survival, size, and photosynthetic efficiencies of larvae and juveniles varied significantly across different familial crosses and temperature treatments. We hypothesize that surviving larvae and juveniles will exhibit differential abundances of sequence variants previously implicated as being transferred during bleaching events. The acquisition of vertically transmitted symbionts by eggs and subsequent maintenance during the larval and juveniles stage would further support the putative role of microbiome-mediated transgenerational acclimatization (MMTA) in increasing heat tolerance and survival under a warming climate.