Distinguishing Lytic and Temperate Infection Dynamics in the Environment

TL;DR

This paper explores how to determine if viruses in an ecosystem primarily kill bacteria (lytic) or allow them to survive (temperate), using simulations and empirical methods.

Contribution

The study bridges theoretical ecology and environmental microbiology by simulating and comparing models of lytic and temperate viral infection dynamics.

Findings

Lytic and temperate models show similar predictions under most conditions but differ under nutrient addition.

A dichotomous key is proposed to help researchers distinguish between lytic and temperate dynamics in ecosystems.

Lytic models become less stable with no host density increase, while temperate models remain stable with elevated host abundances.

Abstract

Viral infection and lysis drive bacterial diversity and abundances, ultimately regulating global biogeochemical cycles. Infection can follow lytic or temperate routes, with lytic dynamics suppressing bacterial population growth and temperate infection enhancing it. Given that bacterial over-proliferation is a pervasive threat to ecosystems, determining which infection dynamic dominates a given ecosystem is a central question in viral ecology. However, the fields that describe and test the rules of viral infection—theoretical ecology and environmental microbiology, respectively—remain disconnected. To address this, we simulated common empirical approaches to analyze and distinguish between the predictions of three theoretical models mechanistically representing lytic to temperate infection dynamics. By doing so, we found that the models have remarkably similar predictions despite their mechanistic differences, as shown by PCA and correlation analyses. Essentially, the models are only discernable under simulated nutrient addition, where lytic models become less stable with no increase in host densities while the temperate model remains stable and has elevated host abundances. Highlighting this difference between the models, we present a dichotomous key illustrating how researchers can determine whether lytic or temperate infection dynamics dominate their ecosystem of interest using common metrics and empirical approaches.

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