Research press release


Nature Microbiology

Ecology: Soil bacteria emit smells to attract animals

ある種の土壌細菌が独特な匂いを放出して動物を誘引し、それが環境中での勢力拡大に役立っていることを明らかにした論文が、Nature Microbiology に掲載される。


今回、Klas Flärdhたちは野外実験と研究室での実験を組み合わせて、ストレプトマイセス属の出す匂いが土壌中に生息する動物、特に節足動物を誘引するかどうかを調べた。ストレプトマイセス属を餌として野外に多数のワナを仕掛けたところ、トビムシ(翅のない小型の節足動物で、昆虫と非常に近い関係にある)がこの細菌に引き寄せられることを明らかにした。研究室での実験では、トビムシはゲオスミンを触角で直接感知することが観察された。また、トビムシがこの細菌を餌にすると、細菌の芽胞がトビムシの体に付着した。その後トビムシは、芽胞を体表につけたまま、または摂取した芽胞を糞として環境中にまき散らした。


Distinct odours emitted from a group of soil bacteria attract animals to help spread the bacteria around their environment, according to a study published this week in Nature Microbiology.

Bacteria make many volatile compounds that can be sensed by larger organisms, including humans.Streptomyces, a group of bacteria commonly present in soil, produce geosmin, an organic compound that has the distinct ‘earthy’ flavour and smell characteristic of soil after it rains. However, the reason why bacteria produce geosmin is unknown.

Klas Flardh and colleagues used a combination of field and laboratory experiments to examine whether the smell of Streptomyces might attract animals that live in the soil, particularly arthropods. Using a network of field traps with Streptomyces as bait, the authors found that springtails — small, wingless arthropods that are closely related to insects — were attracted to the bacteria. In laboratory experiments, the authors observed that springtails can directly sense geosmin with their antennae. They also noted that as the animals fed on the bacteria, bacterial spores adhered to the animals’ bodies. The springtails subsequently dispersed the spores around their environment both by their body surface and by defecation of ingested spores.

The authors suggest that these observations demonstrate an ecological role for such bacterial-derived smells in attracting animals that then disperse the bacteria to the wider environment.

doi: 10.1038/s41564-020-0697-x


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