Reef environments shape microbial partners in a highly connected coral population

Abstract

Evidence is mounting that composition of microorganisms within a host can play an essential role in total holobiont health. In corals, for instance, studies have identified algal and bacterial taxa that can significantly influence coral host function and these communities depend on environmental context. However, few studies have linked host genetics to algal and microbial partners across environments within a single coral population. Here, using 2b-RAD sequencing of corals and metabarcoding of their associated algal (ITS2) and bacterial (16S) communities, we show evidence that reef zones (locales that differ in proximity to shore and other environmental characteristics) structure algal and bacterial communities at different scales in a highly connected coral population ( Acropora hyacinthus ) in French Polynesia. Fore reef (FR) algal communities in Mo'orea were more diverse than back reef (BR) communities, suggesting that these BR conditions constrain diversity. Interestingly, in FR corals, host genetic diversity correlated with bacterial diversity, which could imply genotype by genotype interactions between these holobiont members. Our results illuminate that local reef conditions play an important role in shaping unique host–microbial partner combinations, which may have fitness consequences for dispersive coral populations arriving in novel environments.

How does heat stress affect sponge microbiomes? Structure and resilience of microbial communities of marine sponges from different habitats

“…In heat stress exposed D. antarctica, we observed an increase in the group Burkholderia-Caballeronia-Paraburkholderia (Gammaproteobacteria). ASVs affiliated to this group were among the most abundant in the microbiome of the coral Acropora hyacinthus (Kriefall et al, 2022). Contrastingly, in heat stressed A. cavernosa, we observed an increase in members of several bacterial families (Clostridiaceae, Flavobacteriaceae, Rhodobacteraceae) and two genera (Ruegeria and Winogradskyella).…”

Cophylogeny and specificity between cryptic coral species (Pocillopora spp.) at Mo′orea and their symbionts (Symbiodiniaceae)

“…A mixed mode of symbiont transmission may allow juveniles to have greater flexibility in different environments than strictly vertical transmission. Even if symbionts are transmitted vertically, an individual can host a diverse community of ‘background’ symbionts, even when there is often only one taxa detected, that are transitory and may depend on environmental conditions (Kriefall et al, 2022 ; Lee et al, 2016 ; Rouzé et al, 2019 ; Strader et al, 2022 ). As a result, even in species with vertical transmission, the relationships between scleractinian host and symbiont can be dynamic over ecological timescales (Quigley et al, 2019 ; Reich et al, 2017 ).…”

Cophylogeny and specificity between cryptic coral species (Pocilloporaspp.) at Mo’orea and their symbionts (Symbiodiniaceae)

“…A mixed mode of symbiont transmission may allow juveniles to have greater flexibility in different environments than strictly vertical transmission. Even if symbionts are transmitted vertically, an individual can host a diverse community of ‘background’ symbionts, even when there is often only one taxa detected, that are transitory and may depend on environmental conditions (Lee et al 2016; Rouzé et al 2019; Kriefall et al 2022; Strader et al 2022). As a result, even in species with vertical transmission, the relationships between scleractinian host and symbiont can be dynamic over ecological timescales (Reich et al 2017; Quigley et al 2019).…”