The relative importance of rapid evolution for plant-microbe interactions depends on ecological context

Abstract

Evolution can occur on ecological time-scales, affecting community and ecosystem processes. However, the importance of evolutionary change relative to ecological processes remains largely unknown. Here, we analyse data from a long-term experiment in which we allowed plant populations to evolve for three generations in dry or wet soils and used a reciprocal transplant to compare the ecological effect of drought and the effect of plant evolutionary responses to drought on soil microbial communities and nutrient availability. Plants that evolved under drought tended to support higher bacterial and fungal richness, and increased fungal : bacterial ratios in the soil. Overall, the magnitudes of ecological and evolutionary effects on microbial communities were similar; however, the strength and direction of these effects depended on the context in which they were measured. For example, plants that evolved in dry environments increased bacterial abundance in dry contemporary environments, but decreased bacterial abundance in wet contemporary environments. Our results suggest that interactions between recent evolutionary history and ecological context affect both the direction and magnitude of plant effects on soil microbes. Consequently, an eco-evolutionary perspective is required to fully understand plant-microbe interactions.

Analysing eco‐evolutionary dynamics—The challenging complexity of the real world

“…The endpoint community can be guild members of the same trophic level as the evolving focal species or can be a community of guild members that is affected by evolution of species that interact with the community. An example of the latter is the study of terHorst et al (), in which the impact of evolution of a plant to drought stress was studied on community composition of soil bacteria. The table excludes studies that address interaction modules such as predator–prey interactions (e.g., Becks et al, ; Hiltunen & Becks, ; Yoshida et al, ), host–parasite interactions (Brunner et al, ; Decaestecker et al, ; Frickel et al, ; Masri et al, ) and host–mutualist interactions (Ford et al, ; Macke et al, ), unless they involved whole communities of predators, prey, hosts, parasites or mutualists.…”

“…Several studies, however, do incorporate one or two of the relevant multi‐species dimensions and thus build towards a more comprehensive picture. Quite a few studies (e.g., Bassar et al, ; Farkas et al, ; Fridley & Grime, ; Pantel et al, ; terHorst et al, ; Walsh et al, ) used isolates or populations that evolved in a natural or multi‐species context. However, only three of the nonmicrobial studies (Faillace & Morin, ; Fridley & Grime, ; Rudman et al, ) evaluated the impact of evolution in multiple species at once, hence supporting our claim that a key frontier in eco‐evolution is the effect of multi‐species evolution on ecology.…”

Eco‐evolutionary dynamics in plant–soil feedbacks

“…). In another study, terHorst and colleagues manipulated the evolutionary environment of rapidly cycling Brassica rapa (terHorst, Lennon & Lau ). Plants were exposed to wet or dry soil conditions for three generations and then reciprocally transplanted to wet or dry soils.…”

“…; terHorst, Miller & Levitan ), species diversity (Schreiber, Buerger & Bolnick ; Pantel, Duvivier & Meester ) and ecosystem function (Bassar et al . ; terHorst, Lennon & Lau ). This body of work has demonstrated that, in many cases, it is impossible to understand the ecology of a community without accounting for concurrent evolutionary change.…”

Correction to ‘The relative importance of rapid evolution for plant-microbe interactions depends on ecological context’

“…Correction to 'The relative importance of rapid evolution for plant-microbe interactions depends on ecological context' Casey P. terHorst, Jay T. Lennon and Jennifer A. Lau In a recent publication [1], we reported the effects of contemporary drought and plant evolutionary responses to drought on several aspects of soil microbial communities, including fungal : bacterial ratios. The actual values reported in the paper are in fact bacterial : fungal ratios, rather than their reciprocal.…”