Growth rate and yield are not constrained by a trade-off in microbes
- 1Massachusetts Institute of Technology
Abstract
Ecological theory traditionally posits widespread trade-offs in organismal growth, survival, and reproduction. One core trade-off is the relation between maximum intrinsic growth rate (r) and carrying capacity (K), proposed as a key mechanism explaining species coexistence and the maintenance of biodiversity. To quantify how r relates to K in microbes, we analyzed more than 70,000 microbial growth curves in dozens of media conditions. In this set, we observed a strong positive correlation between r and K, challenging classic life-history expectations of a trade-off. This unexpected "trade-up" can be recovered by a model assuming a non-zero maintenance cost in cells. The model predicts a stronger trade-up under stress conditions that reduce growth rate, consistent with empirical data showing that salinity stress strengthens the trade-up. We also found that community assembly weakens but does not eliminate this positive r-K relationship. The robust growth-yield trade-up between species contrasts with patterns within species. Single-gene knockout datasets in Escherichia coli and budding yeast show no or only weak r-K relationships. Together, our results suggest that the lack of strong trade-offs between growth rate and carrying capacity may be widespread across species, emphasizing the importance of alternative trade-offs and coexistence mechanisms beyond the classical r-K framework.
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BibTeX
@misc{xiong2026growth,
title = {{Growth rate and yield are not constrained by a trade-off in microbes}},
author = {J. Xiong and J. S. Huisman and J. Gore},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.08.750265},
url = {https://www.biorxiv.org/content/10.64898/2026.09.08.750265v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Growth rate and yield are not constrained by a trade-off in microbes
AU - J. Xiong
AU - J. S. Huisman
AU - J. Gore
PY - 2026
DA - 2026/09/08
PB - bioRxiv
DO - 10.64898/2026.09.08.750265
UR - https://www.biorxiv.org/content/10.64898/2026.09.08.750265v1
AB - Ecological theory traditionally posits widespread trade-offs in organismal growth, survival, and reproduction. One core trade-off is the relation between maximum intrinsic growth rate (r) and carrying capacity (K), proposed as a key mechanism explaining species coexistence and the maintenance of biodiversity. To quantify how r relates to K in microbes, we analyzed more than 70,000 microbial growth curves in dozens of media conditions. In this set, we observed a strong positive correlation between r and K, challenging classic life-history expectations of a trade-off. This unexpected "trade-up" can be recovered by a model assuming a non-zero maintenance cost in cells. The model predicts a stronger trade-up under stress conditions that reduce growth rate, consistent with empirical data showing that salinity stress strengthens the trade-up. We also found that community assembly weakens but does not eliminate this positive r-K relationship. The robust growth-yield trade-up between species contrasts with patterns within species. Single-gene knockout datasets in Escherichia coli and budding yeast show no or only weak r-K relationships. Together, our results suggest that the lack of strong trade-offs between growth rate and carrying capacity may be widespread across species, emphasizing the importance of alternative trade-offs and coexistence mechanisms beyond the classical r-K framework.
ER -