Mycoheterotrophy: an uncharted carbon flux in the plant world

Plants need sunlight, water, and soil nutrients to grow. A part of the carbon produced by photosynthesis in the foliage is transferred to root-associated ‘mycorrhizal’ fungi, which help plants to take up nutrients and water from the soil. This carbon can be subsequently taken up by non-green plants that tap into the same fungal network: fully mycoheterotrophic plants. Although fully mycoheterotrophic plants represent only a tiny fraction of plant diversity, they demonstrate that carbon uptake from mycorrhizal fungi is a successful plant strategy to thrive in low light conditions. Indeed, some relatives of fully mycoheterotrophic plants are partially mycoheterotrophic: they can combine autotrophy and mycoheterotrophy when light or seed reserves are insufficient for growth. We currently assume that that up to 9% of all plant species are capable of some form of mycoheterotrophy (mostly orchids). However, based on recent isotopic evidence a new form of partial mycoheterotrophy has been discovered, which advances the hypothesis that an additional 35% of land species are capable of mycoheterotrophy and can survive in low-light habitats by receiving carbon from root-associated arbuscular mycorrhizal fungi.

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Vincent Merckx was selected as Senior Fellow of the Bayreuth Humboldt Centre 2020 with the project "Carbon transfer in arbuscular mycorrhizal networks" and is hosted by BayCEER members Gerhard Gebauer and Johanna Pausch.

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