Mitigation of antagonistic effects on plant growth due to root co‐colonization by dark septate endophytes and ectomycorrhiza

Abstract

Dark septate endophytes (DSE) are very common root colonizers of woody plant species. Ascomycetes of the Phialocephala fortinii s.l.-Acephala applanata species complex (PAC) are the main representatives of DSE fungi in forest ecosystems. PAC and mycorrhizal fungi share the same habitat, but interactions among PAC, mycorrhizal fungi and plants are poorly understood. We compared the effects of single and dual inoculation of Norway spruce seedlings with PAC and the ectomycorrhizal (ECM) fungus Hebeloma crustuliniforme on host growth, degree of mycorrhization and density of endophytic PAC biomass. Single colonization by H. crustuliniforme or PAC significantly reduced plant biomass. Dual colonization reduced or neutralized plant growth depression caused by single fungal colonization. The degree of mycorrhization was independent on PAC colonization, and mycorrhization significantly reduced endophytic PAC biomass. Plant biomass of dually colonized plants positively correlated with PAC biomass. These results demonstrate the ability of dual inoculation of PAC and H. crustuliniforme to neutralize plant growth depression caused by single fungal inoculation. Our explanations of enhanced plant growth in dually inoculated plants are the inhibition of PAC during root colonization by the ECM mantle and ECM-mediated access to plant growth-promoting nutrients resulting from the mineralization of the potting medium by PAC.

Ericoid plant species and Pinus sylvestris shape fungal communities in their roots and surrounding soil

“…Species of the PAC aggregate are reported to have different ecological roles, varying from mutualistic, plant nutrient uptake assisting (Haselwandter & Read, ; Jumpponen et al ., ; Jumpponen, ) to weak saprotrophic or pathogenic (Menkis et al ., ; Addy et al ., ; Lukešová et al ., ). Coexistence of endophytic PAC and mycorrhizal fungi in the plant roots is observed to enhance plant growth probably due to the release of nutrients from the soil by the PAC members (Reininger & Sieber, , ). In our study, members of PAC aggregate were detected from the roots and soils of all the plants studied while being generally more abundant in the P. sylvestris roots than in the soils or ericoid roots.…”

Early rhizosphere microbiome composition is related to the growth and Zn uptake of willows introduced to a former landfill

“…Although the diversity of mycorrhizal fungi has been touted as critical to plant productivity (van der Heijden et al ., ; Hiiesalu et al ., ), this is likely to be most important in mixed plant communities, in which different species associate preferentially with specific mycorrhizal fungi. Reininger and Sieber () showed that co‐inoculation of plants with dark septate endophyte fungi limited reductions in plant growth caused by single inoculants, although an increased number of EM species has been shown to decrease plant biomass (Kennedy et al ., ). In the case of plant growth, the presence of multiple fungi could allow plants to invest only in productive associations, reducing the amount of cheating fungi in the rhizosphere, as has been shown for AM fungi (Kiers et al ., ; Wyatt et al ., ).…”

Consequences of antagonistic interactions between endophytic fungus and bacterium on plant growth and defense responses in Atractylodes lancea

“…A few studies have considered the link between antagonisms between symbionts and their combined effects on host growth [6]. Reininger et al [10] reported that dual inoculation of AMF and dark septate endophytes neutralized plant growth depression caused by endophyte colonization and that this might be attributed to a reduction of endophyte concentration by AMF colonization. This is consistent with the synergistic promotion of plant biomass caused by dual colonization of rhizospheric Pseudomonas spp.…”