Soil organic matter decomposition is a complex process reflecting microbial composition and environmental conditions. Moisture can modulate the connectivity and interactions of microbes. Due to heterogeneity, a deeper understanding of the influence of soil moisture on the dynamics of organic matter decomposition and resultant phenotypes remains a challenge. Soils from a long-term field experiment exposed to high and low moisture treatments were incubated in the laboratory to investigate organic matter decomposition using chitin as a model substrate. By combining enzymatic assays, biomass measurements, and microbial enrichment via activity-based probes, we determined the microbial functional response to chitin amendments and field moisture treatments at both the community and cell scales. Chitinolytic activities showed significant responses to the amendment of chitin, independent of differences in field moisture treatments. However, for other measurements of carbon metabolism and cellular functions, soils from high moisture field treatments had greater potential enzyme activity than soils from low moisture field treatments. A cell tagging approach was used to enrich and quantify bacterial taxa that are actively producing chitin-degrading enzymes. By integrating organism, community, and soil core measurements we show that (i) a small subset of taxa compose the majority (>50%) of chitinase production despite broad functional redundancy, (ii) the identity of key chitin degraders varies with moisture level, and (iii) extracellular enzymes that are not cell-associated account for most potential chitinase activity measured in field soil.
Reichart, Nicholas J., et al. "Impact of moisture on microbial decomposition phenotypes and enzyme dynamics." The ISME Journal, vol. 19, no. 1, Nov. 2025. https://doi.org/10.1093/ismejo/wraf250
Reichart, Nicholas J., Bell, Sheryl, Garayburu-Caruso, Vanessa A., Sadler, Natalie, Zhao, Sharon, & Hofmockel, Kirsten S. (2025). Impact of moisture on microbial decomposition phenotypes and enzyme dynamics. The ISME Journal, 19(1). https://doi.org/10.1093/ismejo/wraf250
Reichart, Nicholas J., Bell, Sheryl, Garayburu-Caruso, Vanessa A., et al., "Impact of moisture on microbial decomposition phenotypes and enzyme dynamics," The ISME Journal 19, no. 1 (2025), https://doi.org/10.1093/ismejo/wraf250
@article{osti_3004933,
author = {Reichart, Nicholas J. and Bell, Sheryl and Garayburu-Caruso, Vanessa A. and Sadler, Natalie and Zhao, Sharon and Hofmockel, Kirsten S.},
title = {Impact of moisture on microbial decomposition phenotypes and enzyme dynamics},
annote = {Soil organic matter decomposition is a complex process reflecting microbial composition and environmental conditions. Moisture can modulate the connectivity and interactions of microbes. Due to heterogeneity, a deeper understanding of the influence of soil moisture on the dynamics of organic matter decomposition and resultant phenotypes remains a challenge. Soils from a long-term field experiment exposed to high and low moisture treatments were incubated in the laboratory to investigate organic matter decomposition using chitin as a model substrate. By combining enzymatic assays, biomass measurements, and microbial enrichment via activity-based probes, we determined the microbial functional response to chitin amendments and field moisture treatments at both the community and cell scales. Chitinolytic activities showed significant responses to the amendment of chitin, independent of differences in field moisture treatments. However, for other measurements of carbon metabolism and cellular functions, soils from high moisture field treatments had greater potential enzyme activity than soils from low moisture field treatments. A cell tagging approach was used to enrich and quantify bacterial taxa that are actively producing chitin-degrading enzymes. By integrating organism, community, and soil core measurements we show that (i) a small subset of taxa compose the majority (>50%) of chitinase production despite broad functional redundancy, (ii) the identity of key chitin degraders varies with moisture level, and (iii) extracellular enzymes that are not cell-associated account for most potential chitinase activity measured in field soil.},
doi = {10.1093/ismejo/wraf250},
url = {https://www.osti.gov/biblio/3004933},
journal = {The ISME Journal},
issn = {ISSN 1751-7370},
number = {1},
volume = {19},
place = {United States},
publisher = {Nature Publishing Group},
year = {2025},
month = {11}}
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
Grant/Contract Number:
AC05-76RL01830
OSTI ID:
3004933
Report Number(s):
PNNL-SA--211809
Journal Information:
The ISME Journal, Journal Name: The ISME Journal Journal Issue: 1 Vol. 19; ISSN 1751-7362; ISSN 1751-7370