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ABSTRACT Host‐associated microbiomes shape the expression of a diverse suite of host traits, ranging from longevity in animals to flowering time in plants. Despite their importance to host traits, the composition of host‐associated microbiomes can fluctuate, and microbiomes of differing composition often have differing impacts on hosts. Fluctuations in microbiome composition can include seasonal shifts that correlate with seasonal phenotypic changes in hosts. Yet, identifying whether these correlated seasonal changes in hosts and microbial communities are causally linked remains difficult because it requires separating the effects of the abiotic environment and host or tissue age from the effects of seasonally altered microbial communities. Here, we used microcosm experiments simultaneously reinoculating axenic duckweeds with microbial communities cultured from different seasons to compare their effects on duckweed growth and trait expression. We found seasonal differences in the effects microbial communities had on duckweeds. Microbial communities cultured from duckweeds in the summer shifted duckweed fronds to be more aggregated (by 5.7%) and slightly more green (by 0.7%) than microbial communities cultured from duckweeds in other seasons, and nonsignificantly increased duckweed growth rates. Inoculation with microbial communities cultured from summer collections also resulted in more total microbial growth in microcosms. These findings enhance our understanding of the influence of seasonality on the complex relationship between microbes and their hosts, with potential future applications in agriculture and medicine.
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This content will become publicly available on March 1, 2027
Observing weak adaptation of duckweeds to their local microbiome depends on local pondwater
Abstract PremisePopulations can locally adapt to the biotic and abiotic factors of environments. However, detecting adaptation to biotic factors can depend on the abiotic conditions in which the adaptation is tested, and vice versa. The microbiome is one important aspect of the biotic environment: Interactions between microbiomes and their hosts are critical for host fitness and trait expression. If hosts adapt to local microbiomes, they may therefore depend on interactions with local microbes to express trait values adapted to the local abiotic environment. MethodsUsingLemna minor(duckweed) as a model host, we examined differences in host fitness when grown in local and nonlocal microbiomes and in local and nonlocal water. We experimentally recombined duckweeds, microbes, and water from four ponds around Durham, New Hampshire (United States) in well‐plate microcosms in a growth chamber. ResultsThe source of duckweeds, microbes, and water all affected microbial growth, duckweed growth, and duckweed traits. However, weak, marginally significant local adaptation resulted in higher frond area only when duckweeds were paired with their local water and local microbes. Microbial growth was also marginally reduced when duckweeds were paired with microbes and water from their local site. ConclusionsWhile microbiome impacts on duckweed growth and traits varied across abiotic contexts, local microbiomes provided only limited growth benefits. Harnessing the effects of plant microbiomes is an exciting area of applied research. Despite our findings, bioprospecting in local microbiomes could still be fruitful: It may be ecologically safer, and other plants may locally adapt to microbiomes.
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- Award ID(s):
- 2300059
- PAR ID:
- 10688017
- Publisher / Repository:
- Botanical Society of America
- Date Published:
- Journal Name:
- American Journal of Botany
- Volume:
- 113
- Issue:
- 3
- ISSN:
- 0002-9122
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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