Scientists inserted bacteria inside fungi and the fungi continued their life cycles and produced bacteria-containing spores. The experiment offers clues to how complex life might have evolved, and how cell features such as mitochondria and chloroplasts might have emerged a billion years ago.
https://www.nature.com/articles/d41586-024-03224-5
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I’ve linked to the news release in the post above. In this comment, for those interested, here’s the link to the peer reviewed journal article:
Inducing novel endosymbioses by implanting bacteria in fungi
https://www.nature.com/articles/s41586-024-08010-x
From the linked article:
Is this how complex life evolved? Experiment that put bacteria inside fungi offers clues
Biologists created a symbiotic system that hints at how cell features such as mitochondria and chloroplasts might have emerged a billion years ago.
Scientists wielding a minute hollow needle — and a bike pump — have managed to implant bacteria into a larger cell, creating a relationship similar to those that sparked the evolution of complex life.
The feat — described1 in Nature on 2 October — could help researchers to understand the origins of pairings that gave rise to specialized organelles called mitochondria and chloroplasts more than one billion years ago.
Yet delivering bacterial cells into the fungi, which have thick cell walls that maintain a high internal pressure, was a challenge. After piercing the wall with the needle, the researchers used a bicycle pump — and later an air compressor — to maintain enough pressure to deliver the bacteria.
After overcoming the initial shock of surgery, the fungi continued their life cycles and produced spores, a fraction of which contained bacteria. When these spores germinated, bacteria were also present in the cells of the next generation of fungi. This showed that the new endosymbiosis could be passed onto offspring — a key finding.
>Scientists think that mitochondria, the organelles that are responsible for cells’ energy production, evolved when a bacterium took up residence inside an ancestor of eukaryotic cells. Chloroplasts emerged when an ancestor of plants swallowed a photosynthetic microorganism.
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>Their approach uses a 500-1000 nanometre wide needle to puncture host cells and then deliver bacterial cells one at a time.
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>Yet delivering bacterial cells into the fungi, which have thick cell walls that maintain a high internal pressure, was a challenge. After piercing the wall with the needle, the researchers used a bicycle pump — and later an air compressor — to maintain enough pressure to deliver the bacteria.
>After overcoming the initial shock of surgery, the fungi continued their life cycles and produced spores, a fraction of which contained bacteria. When these spores germinated, bacteria were also present in the cells of the next generation of fungi. This showed that the new endosymbiosis could be passed onto offspring — a key finding.
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>The basis of this adaptation isn’t clear. Genome sequencing identified a handful of mutations associated with improved germination success in the fungus — which was a strain of R. microsporus not known to carry endosymbionts naturally — and found no changes in the bacteria.
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>Engineering such symbioses could lead to the development of novel organisms with useful traits, such as the ability to consume carbon dioxide or atmospheric nitrogen, says Vorholt. “That’s the idea: to bring in new traits that an organism doesn’t have, and that would be difficult to implement otherwise.”
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What a find, life’s early evolution is as interesting as it gets. This work has huge potential implications.