Header

UZH-Logo

Maintenance Infos

Size evolution in microorganisms masks trade-offs predicted by the growth rate hypothesis


Gounand, Isabelle; Daufresne, Tanguy; Gravel, Dominique; Bouvier, Corinne; Bouvier, Thierry; Combe, Marine; Gougat-Barbera, Claire; Poly, Franck; Torres-Barcelo´, Clara; Mouquet, Nicolas (2016). Size evolution in microorganisms masks trade-offs predicted by the growth rate hypothesis. Proceedings of the Royal Society of London, Series B: Biological Sciences, 283(1845):20162272.

Abstract

Adaptation to local resource availability depends on responses in growth rate and nutrient acquisition. The growth rate hypothesis (GRH) suggests that growing fast should impair competitive abilities for phosphorus and nitrogen due to high demand for biosynthesis. However, in microorganisms, size influences both growth and uptake rates, which may mask trade-offs and instead generate a positive relationship between these traits (size hypothesis, SH). Here, we evolved a gradient of maximum growth rate (mmax) from a single bacterium ancestor to test the relationship among mmax, competitive ability for nutrients and cell size, while controlling for evolutionary history. We found a strong positive correlation between mmax and competitive ability for phosphorus, associated with a trade-off between mmax and cell size: strains selected for high mmax were smaller and better competitors for phosphorus. Our results strongly support the SH, while the trade-offs expected under GRH were not apparent. Beyond plasticity, unicellular populations can respond rapidly to selection pressure through joint evolution of their size and maximum growth rate. Our study stresses that physiological links between these traits tightly shape the evolution of competitive strategies.

Abstract

Adaptation to local resource availability depends on responses in growth rate and nutrient acquisition. The growth rate hypothesis (GRH) suggests that growing fast should impair competitive abilities for phosphorus and nitrogen due to high demand for biosynthesis. However, in microorganisms, size influences both growth and uptake rates, which may mask trade-offs and instead generate a positive relationship between these traits (size hypothesis, SH). Here, we evolved a gradient of maximum growth rate (mmax) from a single bacterium ancestor to test the relationship among mmax, competitive ability for nutrients and cell size, while controlling for evolutionary history. We found a strong positive correlation between mmax and competitive ability for phosphorus, associated with a trade-off between mmax and cell size: strains selected for high mmax were smaller and better competitors for phosphorus. Our results strongly support the SH, while the trade-offs expected under GRH were not apparent. Beyond plasticity, unicellular populations can respond rapidly to selection pressure through joint evolution of their size and maximum growth rate. Our study stresses that physiological links between these traits tightly shape the evolution of competitive strategies.

Statistics

Citations

2 citations in Web of Science®
2 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

1 download since deposited on 07 Feb 2017
1 download since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Evolutionary Biology and Environmental Studies
Dewey Decimal Classification:570 Life sciences; biology
590 Animals (Zoology)
Uncontrolled Keywords:bacteria, growth rate hypothesis, stoichiometry, experimental evolution, r/K strategies, Pseudomonas fluorescens
Language:English
Date:21 December 2016
Deposited On:07 Feb 2017 12:00
Last Modified:08 Dec 2017 23:08
Publisher:Royal Society Publishing
ISSN:0962-8452
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1098/rspb.2016.2272
PubMed ID:28003453

Download