Abstract
Background: Local adaptation, the differential success of genotypes in their native versus foreign environment,
arises from various evolutionary processes, but the importance of concurrent abiotic and biotic factors as drivers of
local adaptation has only recently been investigated. Local adaptation to biotic interactions may be particularly
important for plants, as they associate with microbial symbionts that can significantly affect their fitness and may
enable rapid evolution. The arbuscular mycorrhizal (AM) symbiosis is ideal for investigations of local adaptation
because it is globally widespread among most plant taxa and can significantly affect plant growth and fitness.
Using meta-analysis on 1170 studies (from 139 papers), we investigated the potential for local adaptation to shape
plant growth responses to arbuscular mycorrhizal inoculation.
Results: The magnitude and direction for mean effect size of mycorrhizal inoculation on host biomass depended
on the geographic origin of the soil and symbiotic partners. Sympatric combinations of plants, AM fungi, and soil
yielded large increases in host biomass compared to when all three components were allopatric. The origin of
either the fungi or the plant relative to the soil was important for explaining the effect of AM inoculation on plant
biomass. If plant and soil were sympatric but allopatric to the fungus, the positive effect of AM inoculation was
much greater than when all three components were allopatric, suggesting potential local adaptation of the plant to
the soil; however, if fungus and soil were sympatric (but allopatric to the plant) the effect of AM inoculation was
indistinct from that of any allopatric combinations, indicating maladaptation of the fungus to the soil.
Conclusions: This study underscores the potential to detect local adaptation for mycorrhizal relationships across a
broad swath of the literature. Geographic origin of plants relative to the origin of AM fungal communities and soil
is important for describing the effect of mycorrhizal inoculation on plant biomass, suggesting that local adaptation
represents a powerful factor for the establishment of novel combinations of fungi, plants, and soils. These results
highlight the need for subsequent investigations of local adaptation in the mycorrhizal symbiosis and emphasize
the importance of routinely considering the origin of plant, soil, and fungal components.
Citation
Rúa, M. A., Antoninka, A., Antunes, P. M., Chaudhary, V. B., Gehring, C., Lamit, L. J., . . . Hoeksema, J. D. (2016). Home-field advantage? evidence of local adaptation among plants, soil, and arbuscular mycorrhizal fungi through meta-analysis. BMC Evolutionary Biology, 16(1). doi:10.1186/s12862-016-0698-9