Co-Adaptation of Plants and Communities of Arbuscular Mycorrhizal Fungi to Their Soil Conditions

Abstract

The co-adaptation model formulated on the basis of the reciprocal interaction among plants, arbuscular mycorrhizal fungi (AMF) and soil hypothesizes that plants are adapted to their native AMF. Studies focused on this adaptation bring inconsistent results, however. Previously, we showed that different genotypes of Aster amellus exhibit different percentages of root colonization and that the species is adapted to the abiotic-soil environment combined with its native AMF isolate, but not to a specific AMF isolate alone. Here we asked whether plant populations of A. amellus are adapted to the whole native AMF community and whether there is co-adaptation between plants growing in their native soil and the native AMF community. In the first experiment, we used plants of one population of A. amellus from a marl region and plants of one population from a limestone region and planted them in non-sterile soil from both regions in a full factorial design. In the second experiment, plants from both regions were grown in their native sterilized soil and inoculated with their native AMF community or with the AMF community from the second region. Plants from each region established a specific level of root colonization, and AMF from each region formed a specific abundance of particular morphological structures in A. amellus roots. While we did not find any evidence that the plants are adapted to their whole-soil environment in terms of their growth, we did find evidence that adaptation of plants to native soil conditions could occur via adaptation of AMF to their native soil and plants and association of plants with specific type of AMF colonization. This type of adaptation could lead to the absence of adaptation in terms of plant growth.