Microbe-mediated plant acclimation to drought may be rare in agriculture

Howard, M. M.; Bolin, L. G.; Bogar, G. D.; Evans, S. E.; Lennon, J. T.; Marquart-Pyatt, S. T.; Lau, J. A.

doi:10.64898/2026.04.02.715620

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bioRxiv · 10.64898/2026.04.02.715620

Microbe-mediated plant acclimation to drought may be rare in agriculture

Howard, M. M.·Bolin, L. G.·Bogar, G. D.·Evans, S. E.·Lennon, J. T.·Marquart-Pyatt, S. T.·Lau, J. A.

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Abstract

Microbial communities can shift under drought in ways that enhance plant performance during drought ("microbe-mediated acclimation"). However, it is also possible for microbial communities to shift in ways that worsen the effects of drought ("mal-acclimation"). It is unclear how and where microbe-mediated acclimation vs. mal-acclimation occurs, or if there are types of soils or microbial communities that are more likely to harbor microbes that enhance plant acclimation and limit mal-acclimation. We tested for microbe-mediated plant acclimation/mal-acclimation to drought in soils from 21 maize farms in the midwestern United States, spanning a range of climate, soil types, and management practices. We first conditioned soil microbial communities to drought vs. well-watered conditions in a greenhouse and then tested for microbe-mediated acclimation by growing maize in soils inoculated with the conditioned microbial communities under drought and well-watered conditions. Drought-conditioned soils did not enhance plant performance under drought. In fact, one third of the farms exhibited mal-acclimation, especially under well-watered conditions where wet-conditioned soils reduced plant performance in well-watered contemporary conditions. Farm management practices, climate, soil texture, and microbial diversity generally did not predict when this microbe-mediated mal-acclimation occurred. Overall, these results suggest that in agricultural soils, microbes may frequently impede-rather than facilitate-plant acclimation to soil moisture levels. Open research statementThe plant and soil data used in this study are available via the Environmental Data Initiative repository at https://doi.org/10.6073/pasta/f4a0db3a076cf6d8cef908947f82736e. The bacterial and fungal amplicon sequence data are available via the European Nucleotide Archive under accessions PRJEB110071 and PRJEB109827, respectively.

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Howard, M. M., Bolin, L. G., Bogar, G. D., Evans, S. E., Lennon, J. T., Marquart-Pyatt, S. T., Lau, J. A.. 2026-04-04. Microbe-mediated plant acclimation to drought may be rare in agriculture. https://doi.org/10.64898/2026.04.02.715620

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