The Predation Strategy of Myxococcus xanthus.

Susanne Thiery,Christine Kaimer

doi:10.3389/fmicb.2020.00002

Abstract

Myxobacteria are ubiquitous in soil environments. They display a complex life cycle: vegetatively growing cells coordinate their motility to form multicellular swarms, which upon starvation aggregate into large fruiting bodies where cells differentiate into spores. In addition to growing as saprophytes, Myxobacteria are predators that actively kill bacteria of other species to consume their biomass. In this review, we summarize research on the predation behavior of the model myxobacterium Myxococcus xanthus, which can access nutrients from a broad spectrum of microorganisms. M. xanthus displays an epibiotic predation strategy, i.e., it induces prey lysis from the outside and feeds on the released biomass. This predatory behavior encompasses various processes: Gliding motility and induced cell reversals allow M. xanthus to encounter prey and to remain within the area to sweep up its biomass, which causes the characteristic “rippling” of preying populations. Antibiotics and secreted bacteriolytic enzymes appear to be important predation factors, which are possibly targeted to prey cells with the aid of outer membrane vesicles. However, certain bacteria protect themselves from M. xanthus predation by forming mechanical barriers, such as biofilms and mucoid colonies, or by secreting antibiotics. Further understanding the molecular mechanisms that mediate myxobacterial predation will offer fascinating insight into the reciprocal relationships of bacteria in complex communities, and might spur application-oriented research on the development of novel antibacterial strategies.

Highlights

Predatory bacteria are found in different phyla and apply different mechanisms to kill bacteria of other species and consume their biomass (Jurkevitch, 2007)
Cells coordinate their motility and aggregate into complex multicellular structures, called fruiting bodies, where they differentiate into spores (Figure 1A, white arrowhead). In this mini-review, we summarize our current understanding of the epibiotic predation strategy displayed by the model myxobacterium Myxococcus xanthus
Vegetative growth and predation have been discussed in the context of multicellularity, since Rosenberg et al observed that the growth rate of M. xanthus growing in liquid culture increases depending on cell density, and suggested that nutrient acquisition during predation might involve cooperative behavior similar to a “wolf pack,” where the cooperation between individuals with specific tasks enhances the efficiency of the group: hydrolytic enzymes to degrade prey biomass are secreted by the members of a M. xanthus swarm as common goods and increase in concentration with the number of secreting cells, allowing the efficient degradation of biomass (Rosenberg et al, 1977)

Summary

Introduction

Predatory bacteria are found in different phyla and apply different mechanisms to kill bacteria of other species and consume their biomass (Jurkevitch, 2007). Myxobacteria are ubiquitous in soil and known for their elaborate multicellular behaviors (Keane and Berleman, 2016; Muñoz-Dorado et al, 2016): single cells form large clusters that move slowly along surfaces and secrete enzymes at high concentrations to access nutrients.

Results

Conclusion