Gene study digs into partnership between fungi and plants

Recently evolved toolkit turned wood-decaying fungi into plants' trading partners

red fly agaric mushrooms - Amanita muscaria

TOADSTOOL TOOLKIT Like other mycorrhizal species, fly agaric mushrooms (Amanita muscaria) evolved a specialized toolkit that enables the fungi to trade resources with birch and pine trees. 

Francis Martin/INRA

Dig beneath a plant and you’ll probably find an army of fungi.

Living amid plant roots, most of these mycorrhizal fungi get plant sugars in exchange for providing minerals harvested from soil. Long before the fungi engaged in trade with their plant hosts, though, their fungal ancestors primarily were decomposers, breaking down wood from dead trees. So how did this mutually beneficial relationship with live plants evolve?

Scientists analyzed 49 fungal genomes to find out. They discovered a toolkit of symbiosis genes that evolved independently in different fungi a few times within the last 200 million years. The researchers, from the U.S. Department of Energy’s Joint Genome Institute, the French National Institute for Agricultural Research, and Clark University in Worcester, Mass., report the results February 23 in Nature Genetics.

These fungi still have a few genes for enzymes that break down plant cell walls, as well as ones for proteins linked to the symbiotic lifestyle. Some of these genes — as many as 38 percent — are unique to a single species, suggesting novel genes emerge fairly frequently in symbiosis. 

Helen Thompson is the multimedia editor. She has undergraduate degrees in biology and English from Trinity University and a master’s degree in science writing from Johns Hopkins University.

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