It's been established that many species of fungi generate small electric potentials (c. 100 mV) in their webs of underground fibres.
It's unknown what significance these electrical potentials may or may not have. Some research groups have suggested that they could form the basis of 'signals' between fungi - or even between the fungi and nearby plants.
Example publication : Electrical potentials in the ectomycorrhizal fungus Laccaria bicolor after a rainfall event Fungal Ecology, Volume 63, June 2023, 101229
Also see : Electrical activity in plantsplugin-autotooltip__plain plugin-autotooltip_bigElectrical activity in plants
Electrical signals within plant tissue have been studied since the 1800s. Charles Darwin was interested in possible electrical signals in the Venus Flytrap mechanism (which is still not completely understood). In the 1920s Jagadish Chandra Bose investigated what he called