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研究成果

First Demonstration of a Universal Mechanism by Which Predatory Protists Control Soil Microbial Communities
—Toward Environmentally Harmonious, Next-Generation Agriculture Utilizing Protist “Predation”—

press202530.pdf1.5 MB

2026-03-24
Japan International Research Center for Agricultural Sciences (JIRCAS)
Niigata University
Nagoya University

Key Points

  • This study demonstrated for the first time in the world that predatory protists (predators) are a universal factor influencing the composition of soil microbial communities. 
  • Predators selectively consume dominant bacteria, thereby fostering communities where diverse bacteria can coexist. Furthermore, it was revealed that different predator species drive communities in different directions.
  • By leveraging this mechanism, it is expected that new soil management technologies can be developed to reduce fertilization and pesticide use while improving the efficiency of nutrient cycling and suppressing pathogens.

Overview

A joint research group from JIRCAS, Niigata University, and Nagoya University has, for the first time, demonstrated that predation by single-celled organisms such as amoebae that feed on microbes (predatory protists, hereafter “predators”) is one of the universal factors determining the composition of soil microbial communities.

Soil microbial communities play an essential role in supporting the global environment, including carbon and nutrient cycling. Understanding how these communities are formed has become increasingly important for evaluating soil health and environmental risks. Previous studies have shown that soil microbial communities are influenced by “bottom-up control1” factors such as temperature, moisture, soil pH, soil nutrient levels, and interactions with plants. However, the role of predators in shaping these communities had been examined mainly under artificial conditions such as laboratory cultures, and their actual function in natural environments remained unclear.

In this study, the researchers combined three approaches at different scales—global meta-analysis2, field experiments, and laboratory microcosm experiments3—to comprehensively evaluate the effects of predators on soil microbial communities. The results showed that predators selectively consume the bacteria dominant in a given environment, increasing the relative abundance of previously less noticeable bacteria and causing a “convergence” in community composition across different scales. Furthermore, the direction of convergence differs depending on the predator species, leading to “divergence” of microbial communities. These findings demonstrate for the first time that predators control soil microbial community composition through two opposing processes—convergence and divergence—under natural conditions.

These results open up new possibilities in microbiome engineering4 by utilizing the ecological function of predators known as “top-down control5” to guide soil microbial communities in desirable directions. Applying this knowledge is expected to lead to the development of new soil management technologies that enhance nutrient cycling efficiency and suppress pathogens while reducing fertilizer and pesticide use. This represents a significant step toward achieving next-generation agriculture that balances environmental sustainability with agricultural productivity.

This research was published as an open-access article in the international scientific journal Nature Communications (online version, March 18, 2026, JST).

Related Information

Funding
Operational grant project:“Development of comprehensive agricultural technologies for climate change mitigation and adaptation in Monsoon Asia”
JSPS KAKENHI Grants (JP22K14804, JP24K01654, JP25K02147)

Publication

Authors
Rasit Asiloglu, Hayato Kuno, Mayu Fujino, Seda Bodur, Murat Aycan, Haruka Ishizuka, Shiori Kazama, Shinya Iwasaki, Jun Murase, Naoki Harada, Miwa Arai, Kenta Ikazaki
Title
Predator-mediated local convergence fosters global microbial community divergence
Journal
Nature Communications
DOI: https://doi.org/10.1038/s41467-026-70605-x

Contact

JIRCAS President: KOYAMA Osamu

Program Director: 
HAYASHI Keiichi
Research Staff: 
IKAZAKI Kenta (Senior Researcher, Crop, Livestock and Environment Division)
ARAI Miwa (Senior Researcher, Crop, Livestock and Environment Division)
IWASAKI Shinya (Researcher, Rural Development Division)　
Press Coordinator: 
OMORI Keisuke (Head, Information and Public Relations Office)
Email: info-pr@jircas.go.jp

用語の解説

1 Bottom-up control
A mechanism where microbial community composition is regulated by nutrients and environmental conditions affecting microbial productivity. 
2 Meta-analysis
A method that integrates results from multiple existing studies to identify overall trends and generalize findings.
3 Microcosm experiment
An experimental system that simulates natural ecosystems under controlled conditions to study interactions among organisms and between organisms and their environment. 
4 Microbiome engineering
An applied field aiming to design and manipulate microbial communities to achieve desired functions.
5 Top-down control
A mechanism where microbial community composition is regulated by predation or viral lysis.

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