A Multiscale Analysis of Bacterial Predation

Project Information

JAWS

Grant agreement ID: 885145

DOI

10.3030/885145

Project closed

EC signature date 22 June 2020

Start date 1 January 2021

End date 31 December 2025

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 370 352,00

EU contribution

€ 2 370 352,00

Coordinated by

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France

Periodic Reporting for period 3 - JAWS (A Multiscale Analysis of Bacterial Predation)

Reporting period: 2024-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

In soil ecosystems, plants establish intricate networks with micro-communities consisting of bacteria, fungi, protozoa, and nematodes. Unfortunately, these ecosystems face significant peril due to the dual threats of intensive agriculture and global warming. Predation, a crucial ecological factor, undeniably influences the development and structure of these systems. This phenomenon transcends scales, impacting everything from mammals to viruses. Within soils, predatory bacteria hold ubiquitous presence, implying their vital ecological roles. However, their significance remains inadequately explored, despite their biological significance.

In this research endeavor, we aim to bridge this knowledge gap by delving into the molecular, cellular, and ecological dimensions of collective bacterial predatory behaviors. Specifically, leveraging the well-studied motility aspects from previous research on Myxococcus xanthus, a pervasive model of predatory bacterium, we intend to investigate the mechanisms underlying the infiltration of prey colonies and the subsequent consumption of prey cells through contact-dependent killing. Furthermore, our investigation will encompass the dispersion of Myxococcus cells throughout the prey colony, resembling orchestrated waves that set the stage for the ensuing predatory cycle. While these investigations will unfold within the controlled environment of the laboratory, we will establish connections between the molecular intricacies of predation and the genuine ecological dynamics occurring in the wild. This linkage will be accomplished through genomic analyses of environmental isolates and experimental manipulation of predator-prey interactions.

The culmination of this project will ideally yield a comprehensive, spatially resolved molecular blueprint detailing the Myxococcus predatory cycle. This blueprint, in turn, will serve as a foundational framework for unraveling the ecological roles of these predators. Given that predation can exert a positive influence on biodiversity, our overarching objective is to assess the potential of predatory bacteria to bolster soil biodiversity. By doing so, these bacteria could emerge as a sustainable alternative to pesticides, an increasingly urgent necessity for global agriculture.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Currently, our exploration has centered on the mechanisms by which individual predatory cells identify and eliminate prey cells. Through our investigations, we've unveiled a regulatory connection between motility and prey contact in these cells. This regulatory linkage effectively halts the motility machinery, facilitating the assembly of a killing mechanism that triggers the lysis of prey cells. We've also pinpointed the specific molecular components responsible for prey detection and subsequent disassembly or deactivation of each motility complex. Our current focus revolves around unraveling the intricacies of the actual killing process. Notably, this process is orchestrated by a specialized pilus machinery, extending retractile fibers directly into the prey cells. However, the precise molecular mechanics governing these fibers remain elusive and constitute a significant focal point for the forthcoming phases of our project.

In addition to this, we've investigated how thousands of bacterial cells synchronize their motility to infiltrate prey colonies, giving rise to remarkable traveling waves that ripple across the entire expanse of the prey colony. Remarkably, our findings have demonstrated that this complex behavior can be deciphered using elementary principles—long-range cellular alignments on the prey matrix and collision-induced directional adjustments, reminiscent of traffic congestion dynamics. To model these behaviors, we've devised a computational framework, which we intend to employ to delve further into the multicellular transitions observed during the predation cycle.

Lastly, we've undertaken experimental evolution to identify and cultivate superior predators. Among these, one particular predator displayed significant metabolic adaptations, shedding light into the nutritional aspects of the predation process and the associated metabolic pathways.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The project has established foundational knowledge towards unraveling the molecular mechanisms of predation for the very first time. The outcomes derived from the initial phase have brought fresh insights into motility, its modulation in response to prey presence, and have paved the way for investigating an unprecedented killing apparatus that holds prevalence among predatory bacteria. The subsequent stages of the project are poised to delve into comprehending the intricacies of this killing mechanism, particularly in its versatility across a diverse array of prey species.

Our team has successfully formulated a computational model of the transitions observed in predatory multicellular behaviors. This model has been instrumental in determining the mechanism of the propagation of predatory waves. Moreover, we intend to expand its scope to encompass a comprehensive understanding of how prey colonies are collectively infiltrated and how the rippling patterns ultimately give rise to three-dimensional fruiting bodies during the culmination of the predatory cycle. Consequently, this model could potentially establish a hitherto unprecedented link between individual behaviors and multicellular patterns spanning the entirety of the predatory process.

In addition, we will persist in our exploration of predatory nutrition and metabolism, specifically examining the impact of environmental factors on these pathways. Through the sampling of environmental isolates, we hope to bridge the gap between laboratory-based findings and the actual ecological behavior of these predatory bacteria.

To conclude, this project demonstrates a resolute commitment to dissecting predatory mechanisms within the controlled laboratory environment, while simultaneously assessing their ecological implications. The endeavor stands as an ambitious pursuit aimed at shedding light on the mechanisms of predation and its broader ecological significance.