Host specificity of microbiome assembly and its fitness effects in phytoplankton

Abstract

Insights into symbiosis between eukaryotic hosts and their microbiomes have shifted paradigms on what determines host fitness, ecology, and behavior. Questions remain regarding the roles of host versus environment in shaping microbiomes, and how microbiome composition affects host fitness. Using a model system in ecology, phytoplankton, we tested whether microbiomes are host-specific, confer fitness benefits that are host-specific, and remain conserved in time in their composition and fitness effects. We used an experimental approach in which hosts were cleaned of bacteria and then exposed to bacterial communities from natural environments to permit recruitment of microbiomes. We found that phytoplankton microbiomes consisted of a subset of taxa recruited from these natural environments. Microbiome recruitment was host-specific, with host species explaining more variation in microbiome composition than environment. While microbiome composition shifted and then stabilized over time, host specificity remained for dozens of generations. Microbiomes increased host fitness, but these fitness effects were host-specific for only two of the five species. The shifts in microbiome composition over time amplified fitness benefits to the hosts. Overall, this work solidifies the importance of host factors in shaping microbiomes and elucidates the temporal dynamics of microbiome compositional and fitness effects.

<em> </em>Current Research on Microbe-Plastic Interactions in the Marine Environment

“…Perhaps the most interesting aspect about eukaryotes in the plastisphere, however, is their potential to shape the composition of the prokaryotic community inhabiting the biofilm through eukaryoteprokaryote interactions and close associations 12,46,85,127,150 , some of which are known to be speciesspecific 222,223 . Bacteria can benefit from phytoplankton by gaining access to their cell exudates that provide a source of carbon, energy and nutrients 46,127,224,225 , as well as oxygen produced via photosynthesis (reviewed by Stocker and Seymour 226 ).…”

Halophytes Increase Rhizosphere Microbial Diversity And Network Complexity In Inland Saline Ecosystem

“…The numbers of fungal indicator OTUs were signi cantly larger in C. epigeios and P. australis rhizospheres (96 and 49) than the other plant rhizospheres and the bulk soils (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36). The K. foliatum rhizosphere and the bulk soils shared many fungal indicator OTUs (93), most of which belonged to Ascomycota, while the rhizospheres of the six halophytes only shared a small number of fungal indicator OTUs among them (Fig.…”

“…Both the diversity and association of soil microbiota respond sensitively to environmental changes, and are tightly correlated with the services that the soil microbiota provide, including nutrient cycling, soil and ecosystem functions, restoration of degraded land, mitigation of environmental change, resistance to stress [23,[25][26][27]. Given that the response of soil microbial communities to environmental changes is closely associated with plant metabolism and root exudates [28][29][30][31][32][33], these associations occur mainly in the rhizosphere and depend on the plant tness and health status [20,34]. Although the diversity and composition of soil microbial community in saline soils were previously reported [35][36][37][38][39], it is still unclear how plant in uence the microbial co-occurring network and microbes' associations in saline ecosystem, particularly for the rhizosphere soils.…”

Host-symbiont population genomics provide insights into partner fidelity, transmission mode and habitat adaptation in deep-sea hydrothermal vent snails

“…The degree of partner fidelity and its effect on symbiont composition can have dramatic impacts on holobiont functioning (Ginete and Goodrich-Blair 2021). For example, host-symbiont specificity, both at the species and genotype level, is crucial for light production in bioluminescent squid (Verma and Miyashiro 2013), while shifts in microbiome assemblages have been shown to affect phytoplankton growth rates (Jackrel et al 2021) and the efficiency of nitrogen fixation in nodule-forming legumes (Wang et al 2018;Allito et al 2020;Walker et al 2020). Despite its importance for host biology, the taxonomic level of partner specificity as well as the relative contributions of host genetic, environmental and geographical factors to symbiont composition remain understudied in the majority of horizontally transmitted symbioses.…”

“…The degree of partner fidelity and its effect on symbiont composition can have dramatic impacts on holobiont functioning (6). For example, host-symbiont specificity, both at the species and genotype level, is crucial for light production in bioluminescent squid (7), while shifts in microbiome assemblages have been shown to affect phytoplankton growth rates (8) and the efficiency of nitrogen fixation in nodule-forming legumes (9)(10)(11).…”