Fungi-Savvy Herbs Thrive in Their Own Soil, Study Finds

Beneath every grassland and meadow lies an invisible economy of trade, rivalry and quiet negotiation. Plants do not merely compete for light and water; they also shape, and are shaped by, the microscopic communities living in the soil around their roots. A new study published in the journal Plant and Soil suggests that one particular trait—how strongly a plant responds to mycorrhizal fungi, the symbiotic soil fungi that colonize most land plants—may quietly determine how well a herbaceous species fares when it grows in soil previously occupied by its own kind. The finding offers a fresh explanation for why some plant species dominate patches of ground while others fade, and why diverse herbaceous communities can remain stable over space and time.

The research, led by Stavros D. Veresoglou of the State Key Laboratory of Biocontrol at Sun Yat-sen University’s School of Ecology in Shenzhen, together with David Johnson of the Lancaster Environment Centre at Lancaster University and a large team of coauthors, set out to test a deceptively simple hypothesis: that herbaceous plant species which respond strongly to mycorrhizal fungi experience more favorable plant-soil feedbacks than species that respond weakly. Plant-soil feedback describes the loop by which a plant modifies the chemical and biological properties of its soil, and those modifications in turn affect the growth of the next generation of plants, whether of the same or different species. Negative feedbacks, often driven by species-specific pathogens accumulating in the rhizosphere, tend to prevent any single species from crowding out its neighbors. Positive feedbacks can do the opposite, allowing dominant species to reinforce their own success.

Mycorrhizal fungi, particularly the arbuscular mycorrhizal fungi that partner with the majority of herbaceous plants, sit at the heart of this loop. They extend the effective reach of root systems, extracting phosphorus and other poorly mobile nutrients from soil pores that roots alone cannot exploit. In exchange, the fungi receive carbon from their plant hosts. But the partnership is not uniform across the plant kingdom. Some species, such as many members of the cabbage family, have fine, densely branched roots and root hairs that make them largely self-sufficient, and they gain little from fungal colonization. Others, with coarser root architectures, depend heavily on their fungal partners and show dramatic growth responses when those partners are present. Ecologists refer to this gradient as mycorrhizal responsiveness, and it has long been suspected to influence how plants interact with their soil communities.

To test the hypothesis, the researchers took a synthetic approach rather than growing plants from scratch. They extracted plant-soil feedback information for herbaceous species from a recent meta-analysis of feedback studies, most of which were conducted under controlled greenhouse conditions, and then collated that information with three independent sources of mycorrhizal responsiveness data. These data sources included large compilations of plant growth responses to mycorrhizal inoculation, drawing on datasets such as the global MycoDB database of plant responses to mycorrhizal fungi. By matching species across datasets, the team could ask a question that no single experiment could answer: do species that respond strongly to mycorrhizal fungi systematically differ in how their own soils affect their performance?

The answer, according to the study, is yes. The analysis supported the hypothesis that mycorrhizal responsive plants receive more positive plant-soil feedbacks than their less responsive counterparts. Strikingly, this pattern held regardless of whether the mycorrhizal response itself was positive or negative. In other words, it was not simply that plants that benefit from fungi also benefit from their own soil microbes. Rather, the sheer magnitude of a species’ engagement with the mycorrhizal symbiosis—its responsiveness, whether up or down—predicted the sign and strength of its feedback with the soil it leaves behind. The result was robust to most of the sensitivity tests the authors carried out, including checks designed to account for the phylogenetic relatedness of the species in the dataset, a common confounding factor in comparative plant ecology.

The technical logic behind this pattern likely traces back to root architecture and what ecologists call the Baylis postulate, the classical idea that plants with coarse roots and few root hairs tend to be more dependent on mycorrhizal fungi. Species at the responsive end of this spectrum invest in fungal partnerships and, in doing so, cultivate soil communities that include abundant and diverse arbuscular mycorrhizal fungi. Those fungi can buffer the next generation against soil-borne pathogens, counteracting the negative density-dependent effects—sometimes called Janzen-Connell effects—that would otherwise suppress seedlings growing near conspecific adults. Prior work has shown that arbuscular mycorrhizal fungi can counteract pathogen-driven mortality in grasslands, and that fungal diversity regulates plant-soil feedbacks in temperate grassland systems. The new analysis ties these threads together at the scale of whole species pools.

Why does this matter for understanding plant communities? Ecologists have long noted that the processes structuring plant communities are understood far better in forests than in herbaceous systems such as grasslands, prairies and meadows. In forests, mycorrhizal type—whether trees partner with arbuscular or ectomycorrhizal fungi—has been shown to shape population dynamics through plant-soil feedbacks. Herbaceous communities, however, are dominated almost entirely by arbuscular mycorrhizal plants, so the coarse binary classification used in forests loses its explanatory power. Mycorrhizal responsiveness, a continuous trait that varies even among closely related herbs, offers a finer-grained alternative. The new study suggests that this trait may be an underappreciated mechanism conferring spatiotemporal stability across herbaceous plant communities, helping to explain how so many species can coexist on seemingly homogeneous ground.

The authors also point to a subtle ecological trade-off embedded in their findings. Mycorrhizal responsive plant species may receive less negative plant-soil feedback, but they most likely experience higher interspecific competition. This makes intuitive sense: a species that performs well in its own soil and can re-establish successfully where it has grown before will also be a strong competitor in mixtures, drawing intense pressure from neighbors that are similarly capable. Less responsive species, by contrast, may suffer harsher feedbacks from their own soils but face weaker competitive suppression. The interplay between these two forces could promote a balance of mycorrhizal responsive and less-mycorrhizal responsive species within herbaceous systems, a dynamic equilibrium in which neither group wins outright. This echoes earlier theoretical work proposing that plant responsiveness to mycorrhiza regulates coexistence, and recent findings that mycorrhizal fungi reduce fitness differences between plants even as intrinsic responsiveness differences determine coexistence outcomes.

The study also carries practical implications. Restoration ecologists and land managers increasingly manipulate soil communities, whether through inoculation with native mycorrhizal fungi or through cover crop choices that shape the soil microbiome. If a species’ mycorrhizal responsiveness predicts how it will fare in soil it has itself conditioned, then responsiveness could serve as a screening trait for restoration projects, helping practitioners predict which species will establish persistently in a given soil and which will struggle. The trait may likewise help explain invasion success: previous research has asked whether responsiveness to arbuscular mycorrhizal fungi depends on plant invasive status, and the new framework provides a mechanism by which responsive invaders could gain a foothold through favorable soil legacies.

Caveats remain. The feedback data underpinning the analysis derive largely from greenhouse experiments, where soil biota are concentrated in small pots and conditions are far more uniform than in the field; the authors themselves frame their conclusion around greenhouse settings. Field validation will be needed to confirm that the same relationship between responsiveness and feedback holds under natural variation in climate, grazing, nutrient deposition and land use, particularly as climate change is known to shift plant-soil feedbacks. Nonetheless, the study opens a compelling new window onto the hidden architecture of grassland diversity. It suggests that the fate of a herbaceous plant may be written not only in its genes or its competitive prowess, but in the fungal partnerships it cultivates and the microbial legacy it leaves in the soil beneath it—a legacy that will greet its own offspring, for better or worse, when they next take root.

Subject of Research: The relationship between mycorrhizal responsiveness and plant-soil feedbacks in herbaceous plant species

Article Title: Under greenhouse settings, mycorrhizal responsive herbs establish better in their own soil compared to less responsive counterparts

Article References: Under greenhouse settings, mycorrhizal responsive herbs establish better in their own soil compared to less responsive counterparts. (n.d.). https://doi.org/10.1007/s11104-026-09048-8

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09048-8

Keywords: mycorrhizal fungi, plant-soil feedback, herbaceous plants, arbuscular mycorrhiza, root architecture, plant ecology, grassland diversity, soil microbiome, coexistence, Baylis postulate, plant communities, ecology