Do mycorrhiza only form with angiosperm?

Which plants actually form mycorrhizas?

The short answer is: nearly all of them. One review describes different groups of fungi forming symbiotic associations with "almost all groups of plants, from bryophytes to seed plants, i.e., gymnosperms and angiosperms" [4]. Bryophytes are the mosses and their relatives—small, simple plants that never flower. Gymnosperms are the cone-bearing plants like pines and conifers. Both partner with mycorrhizal fungi, so flowering plants are only one part of the picture.

The scale is striking. Over 320,000 existing vascular and non-vascular plant species can develop mycorrhizas, and within that enormous group the angiosperms are the largest and most varied [5]. That is why so much research focuses on crops and flowering plants: they are the biggest slice of the pie, not the whole pie.

It also helps to know that "mycorrhiza" is not one thing. There are several distinct types—arbuscular, ecto-, orchid, and ericoid mycorrhizas are the four main ones—each with its own morphology and function, shaped by over 400 million years of co-evolution between plants and fungi [5]. Different plant groups tend to pair with different fungal types, which is part of why the partnership spans so many kinds of plants.

Why does it look like a flowering-plant story?

Much of the visible research is about crops, and crops are angiosperms. Arbuscular mycorrhizal fungi (AMF) can form root symbioses with about 80% of angiosperms, including wheat, maize, and rice [1][2]. When studies test how these fungi affect growth or disease resistance, they naturally use agricultural flowering plants. A 2023 study, for example, tested six rice cultivars against three AMF genotypes and found that all three fungi colonized the roots of all six rice varieties, though how well they did varied by pairing [1][2].

That focus can create a misleading impression. Seeing paper after paper on rice, wheat, and tomato might suggest the symbiosis is an angiosperm specialty. But the same editorial that notes angiosperms are the largest host group also describes mycorrhizal fungi partnering with ferns, and it lists trees, bushes, herbs, and staple crops as examples within the angiosperm diversity rather than as the boundary of the symbiosis [5]. The narrow research lens reflects what is economically useful to study, not the true range of the partnership.

What does the fungus actually do for its host?

Across plant groups, the basic trade is similar. The plant makes organic products by photosynthesis and supplies them to the fungus; the fungus supplies water and mineral nutrients such as phosphorus from the soil [4]. This is described as a mild form of parasitism that functions as mutualism, because both partners benefit [4]. The fungus can also help protect plants from pathogens and improve soil quality [4].

The benefits are not automatic or uniform, though. In the rice study, mycorrhization produced effects on plant dry weight ranging from a 21% decrease to a 227% increase depending on which rice variety was paired with which fungus [1]. One fungal genotype, Rhizophagus irregularis, was the most compatible partner, raising rice dry weight by 28% to 178% and reducing leaf symptoms from bacterial infection by 6% to 27% [1]. So the partnership's payoff depends heavily on the specific plant and fungus involved—a pattern that likely applies beyond rice, though the evidence here comes from that crop.

There is also a longer-term idea worth flagging as a hypothesis rather than a settled fact. One group of researchers proposes that mycorrhizal associations may persist over evolutionary time as a kind of "bet-hedging": the fungus might help plants survive occasional harsh years, even if it offers little or no benefit in good years [3]. Under this view, short experiments could understate the partnership's value because they miss the rare stressful seasons where it matters most. The authors present this as a possibility to be tested, not a demonstrated function.

If the partnership is so widespread, does the specific partner matter?

Yes—compatibility is not one-size-fits-all. The rice work shows that both the plant variety and the fungal genotype shape the outcome, driving beneficial, neutral, or even negative effects on growth, and in some cases changing how well the plant resists infection [2]. The researchers traced these differences to distinct patterns of gene activity in the leaves, suggesting that molecular markers of compatibility can differ between plant–fungus pairings [2].

This matters for anyone thinking about applying mycorrhizas in agriculture or forestry. Because the symbiosis spans bryophytes through seed plants [4], and because outcomes depend on the specific pairing [1][2], the practical lesson is that "adding mycorrhizal fungi" is not a single lever. Which fungus you pair with which plant—and under what conditions—can change whether the result is helpful, neutral, or harmful.

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