Surfactants Help Bacteria Hitchhike on Leaves

Greg Howard
30th April, 2024

Surfactants Help Bacteria Hitchhike on Leaves

Image Source: Natural Science News, 2024

Key Findings

  • In a Berlin study, bacteria Pantoea eucalypti 299R grew better with surfactant-producing Pseudomonas sp. FF1 on surfaces
  • Surfactants from Pseudomonas helped Pantoea bacteria spread and access nutrients on swarming agar plates
  • On plant leaves, Pantoea showed increased growth in the presence of surfactant-producing Pseudomonas, indicating a beneficial interaction
Understanding the complex relationships between plants and the microorganisms that live on them is crucial for grasping how ecosystems function and how they might change in a rapidly changing world. A recent study from the Freie Universität Berlin[1] has shed light on the interactions between different bacteria on the surface of leaves, an area known as the phyllosphere. This research builds on a foundation of previous studies that have explored the microbial ecology of plant surfaces[2][3][4][5], and it takes a step further by examining how the production of certain compounds by one type of bacteria can benefit another, potentially influencing the overall health and growth of the host plant. The focus of the study is on a bacterium called Pantoea eucalypti 299R (Pe299R), which can be found on the leaves of many plants. Researchers investigated how Pe299R interacts with a group of bacteria known as pseudomonads, specifically a strain called Pseudomonas sp. FF1 (Pff1), which is known to produce surfactants—compounds that reduce surface tension. Surfactants are common in cleaning products because they can break up oil and grease, but in nature, they can help bacteria move across surfaces or protect them against harsh conditions. The experiments were designed to observe what happens when Pe299R is grown with Pff1 and a mutant version of Pff1 that cannot produce surfactants (Pff1ΔviscB). The researchers grew the bacteria together in three different environments: a nutrient-rich broth, on swarming agar plates that mimic a solid surface, and directly on plant leaves. What they found was intriguing: in the nutrient broth, Pe299R grew the same whether it was with Pff1 or the mutant Pff1ΔviscB. However, on the swarming agar plates, Pe299R grew significantly better when it was with Pff1, suggesting that the surfactants produced by Pff1 helped Pe299R move and perhaps access nutrients more effectively. The most compelling findings came from the experiments conducted on actual plant leaves. Here, the researchers used a tool called a single-cell bioreporter to track the success of individual Pe299R cells. They discovered that when Pe299R was co-inoculated on the leaves with Pff1, certain subpopulations of Pe299R experienced a boost in growth that did not occur when Pff1ΔviscB was present. This indicates that the surfactants produced by Pff1 have a beneficial effect on Pe299R, specifically during the colonization of leaf surfaces. These results are significant because they suggest that the production of surfactants by pseudomonads can influence the structure of bacterial communities on leaves by aiding the movement and establishment of other bacteria like Pe299R. This finding is consistent with previous research that has highlighted the importance of bacterial movement and interactions in shaping microbial communities on plant surfaces[4]. It also complements studies that have emphasized the need to understand the individual behaviors of bacterial cells in complex environments[5]. Prior studies have shown that plants and their associated bacteria can influence each other's distribution and that certain bacterial strains can have outsized effects on community structure[2][3][4]. The current study adds to this body of work by demonstrating a specific mechanism—surfactant production—that can facilitate these interactions. It also underscores the importance of considering both the individual and collective behaviors of bacteria when trying to understand their ecology and evolution[5]. In summary, the research from the Freie Universität Berlin provides new insights into how the production of surfactants by certain bacteria can benefit other bacteria during the colonization of plant surfaces. This work not only expands our understanding of the complex web of interactions in the phyllosphere but also has potential applications in agriculture, where manipulating microbial communities on crop leaves could lead to better plant growth and disease resistance.

BiochemEcologyPlant Science


Main Study

1) Hitching a Ride in the Phyllosphere: Surfactant Production of Pseudomonas spp. Causes Co-swarming of Pantoea eucalypti 299R

Published 29th April, 2024

Related Studies

2) Plant-bacteria associations are phylogenetically structured in the phyllosphere.

3) Microbial life in the phyllosphere.

4) Synthetic microbiota reveal priority effects and keystone strains in the Arabidopsis phyllosphere.

5) Phyllosphere microbiology: at the interface between microbial individuals and the plant host.

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