Effect of different root endophytic fungi on plant community structure in experimental microcosms

Abstract

Understanding the effects of root‐associated microbes in explaining plant community patterns represents a challenge in community ecology. Although typically overlooked, several lines of evidence point out that nonmycorrhizal, root endophytic fungi in the Ascomycota may have the potential to drive changes in plant community ecology given their ubiquitous presence, wide host ranges, and plant species‐specific fitness effects. Thus, we experimentally manipulated the presence of root endophytic fungal species in microcosms and measured its effects on plant communities. Specifically, we tested whether (1) three different root endophyte species can modify plant community structure; (2) those changes can also modified the way plant respond to different soil types; and (3) the effects are modified when all the fungi are present. As a model system, we used plant and fungal species that naturally co‐occur in a temperate grassland. Further, the soil types used in our experiment reflected a strong gradient in soil texture that has been shown to drive changes in plant and fungal community structure in the field. Results showed that each plant species responded differently to infection, resulting in distinct patterns of plant community structure depending on the identity of the fungus present. Those effects depended on the soil type. For example, large positive effects due to presence of the fungi were able to compensate for less nutrients levels in one soil type. Further, host responses when all three fungi were present were different from the ones observed in single fungal inoculations, suggesting that endophyte–endophyte interactions may be important in structuring plant communities. Overall, these results indicate that plant responses to changes in the species identity of nonmycorrhizal fungal community species and their interactions can modify plant community structure.

A novel experimental system using the liverwort Marchantia polymorpha and its fungal endophytes reveals diverse and context‐dependent effects

“…The many impacts of fungal endophytes on their hosts make these microbes critical in structuring plant communities and the terrestrial ecosystems they sustain (Rudgers et al, 2004;Afkhami & Strauss, 2016;Aguilar-Trigueros & Rillig, 2016). The study of plants as holobionts composed of host and complex microbiome is still in the early stages (Vandenkoornhuyse et al, 2015) and many studies only investigate the effects of a few individual fungi on their hosts.…”

“…The study of plants as holobionts composed of host and complex microbiome is still in the early stages (Vandenkoornhuyse et al, 2015) and many studies only investigate the effects of a few individual fungi on their hosts. Experiments that have tested the effects of many strains or combinations of multiple fungi have revealed that endophyte effects can differ between closely related fungi and that interactions between microbiome members matter for plant host outcomes (Violi et al, 2007;Mandyam et al, 2012Mandyam et al, , 2013Reininger et al, 2012;Aguilar-Trigueros & Rillig, 2016).…”

Invisible but consequential: root endophytic fungi have variable effects on belowground plant–insect interactions

“…However, since plant roots are consistently exposed to and colonized by diverse fungal species (Wearn et al. ), it will be critical that future studies investigate whether different combinations of endophytic and mycorrhizal fungi interact synergistically or antagonistically in plant tissues and how their overall effects on plant defense change with environmental conditions (Partida‐Martínez and Heil , Aguilar‐Trigueros and Rillig ).…”

“…While the root endophytic fungus P. indica has attracted increasing attention for its potential to enhance growth and performance of a wide range of crop plants (Weiß et al. ), the ecological significance of other endophyte species remains poorly characterized (Aguilar‐Trigueros and Rillig ).…”

Effect of the anther‐smut fungus Microbotryum on the juvenile growth of its host Silene latifolia

“…Plants are host to a wide variety of microbes that do not appear to cause obvious disease, and there is growing realization that many of these endophytes can have cryptic effects on plant growth, physiology, and fitness (Rodriguez et al., ; Aguilar‐Trigueros and Rillig, ). Microbes are considered to be pathogens if they cause obvious disease symptoms, and generally these symptoms become evident after the pathogen has successfully established itself within the host.…”