Prevailing Negative Soil Biota Effect and No Evidence for Local Adaptation in a Widespread Eurasian Grass

Abstract

BackgroundSoil biota effects are increasingly accepted as an important driver of the abundance and distribution of plants. While biogeographical studies on alien invasive plant species have indicated coevolution with soil biota in their native distribution range, it is unknown whether adaptation to soil biota varies among populations within the native distribution range. The question of local adaptation between plants and their soil biota has important implications for conservation of biodiversity and may justify the use of seed material from local provenances in restoration campaigns.Methodology/Principal FindingsWe studied soil biota effects in ten populations of the steppe grass Stipa capillata from two distinct regions, Europe and Asia. We tested for local adaptation at two different scales, both within (ca. 10–80 km) and between (ca. 3300 km) regions, using a reciprocal inoculation experiment in the greenhouse for nine months. Generally, negative soil biota effects were consistent. However, we did not find evidence for local adaptation: both within and between regions, growth of plants in their ‘home soil’ was not significantly larger relative to that in soil from other, more distant, populations.Conclusions/SignificanceOur study suggests that negative soil biota effects can prevail in different parts of a plant species' range. Absence of local adaptation points to the possibility of similar rhizosphere biota composition across populations and regions, sufficient gene flow to prevent coevolution, selection in favor of plasticity, or functional redundancy among different soil biota. From the point of view of plant - soil biota interactions, our findings indicate that the current practice of using seeds exclusively from local provenances in ecosystem restoration campaigns may not be justified.

Mycorrhizal Symbiosis and Local Adaptation in Aster amellus: A Field Transplant Experiment

“…The absence of local adaptation has also been reported in other plant species, such as Carlina vulgaris [32], Crotalaria pallida [33], Stipa capillata [34] and Helleborus foetidus [35]. Each of these studies provided different explanations for the lack of local adaptation.…”

Evolutionary ecology of plant–microbe interactions: soil microbial structure alters selection on plant traits

“…(2010) observed plant local adaptation to soils that differed in microbial structure and soil effects on the heritability of plant traits. By contrast, Wagner et al. (2011) found no evidence that plant populations were locally adapted to soil biota.…”

“…Although few studies have investigated evolutionary interactions between plants and their total below-ground community, Pregitzer et al (2010) observed plant local adaptation to soils that differed in microbial structure and soil effects on the heritability of plant traits. By contrast, Wagner et al (2011) found no evidence that plant populations were locally adapted to soil biota. In more tightly linked, pairwise symbiotic relationships, microbially mediated adaptive changes 222 Research New Phytologist have been documented for a wide variety of systems from aphids and their Buchnera endosymbionts (Zilber-Rosenberg & Rosenberg, 2008) to plants and their mycorrhiza mutualists (Johnson et al, 2010).…”

Does responsiveness to arbuscular mycorrhizal fungi depend on plant invasive status?

“…For instance, other plant-AMF interactions are conceivable with other pairings of AMF communities (species and genotypes), plant genotypes (e.g., Klironomos, 2003;Stahl & Smith, 1984), and growth conditions. Additional experiments that incorporate population and genotypic variability are necessary to quantify general effects of soil microbes across a plant's range (Callaway, Bedmar, Reinhart, Silvan, & Klironomos, 2011;Reinhart, Royo, van der Putten, & Clay, 2005;Wagner, Antunes, Ristow, Lechner, & Hensen, 2011).…”