Can plants build their niche through modulation of soil microbial activities linked with nitrogen cycling? A test with Arabidopsis thaliana.

In natural systems, different plant species have been shown to modulate specific nitrogen (N) cycling processes so as to meet their N demand, thereby potentially influencing their own niche. This phenomenon might go beyond plant interactions with symbiotic microorganisms and affect the much less explored plant interactions with free-living microorganisms involved in soil N cycling, such as nitrifiers and denitrifiers. Here, we investigated variability in the modulation of soil nitrifying and denitrifying enzyme activities (NEA and DEA, respectively), and their ratio (NEA : DEA), across 193 Arabidopsis thaliana accessions. We studied the genetic and environmental determinants of such plant-soil interactions, and effects on plant biomass production in the next generation. We found that NEA, DEA, and NEA : DEA varied c. 30-, 15- and 60-fold, respectively, among A. thaliana genotypes and were related to genes linked with stress response, flowering, and nitrate nutrition, as well as to soil parameters at the geographic origin of the analysed genotypes. Moreover, plant-mediated N cycling activities correlated with the aboveground biomass of next-generation plants in home vs away nonautoclaved soil, suggesting a transgenerational impact of soil biotic conditioning on plant performance. Altogether, these findings suggest that nutrient-based plant niche construction may be much more widespread than previously thought.

AraDiv: a dataset of functional traits and leaf hyperspectral reflectance of Arabidopsis thaliana.

Data from functional trait databases have been increasingly used to address questions related to plant diversity and trait-environment relationships. However, such databases provide intraspecific data that combine individual records obtained from distinct populations at different sites and, hence, environmental conditions. This prevents distinguishing sources of variation (e.g., genetic-based variation vs. phenotypic plasticity), a necessary condition to test for adaptive processes and other determinants of plant phenotypic diversity. Consequently, individual traits measured under common growing conditions and encompassing within-species variation across the occupied geographic range have the potential to leverage trait databases with valuable data for functional and evolutionary ecology. Here, we recorded 16 functional traits and leaf hyperspectral reflectance (NIRS) data for 721 widely distributed Arabidopsis thaliana natural accessions grown in a common garden experiment. These data records, together with meteorological variables obtained during the experiment, were assembled to create the AraDiv dataset. AraDiv is a comprehensive dataset of A. thaliana's intraspecific variability that can be explored to address questions at the interface of genetics and ecology.

Ecological insights from assessments of phenotypic plasticity in a Neotropical species of Drosophila.

Several authors have called attention to the evolutionary importance of phenotypic plasticity and niche construction, because such phenomena require a new status and a new perspective. Drosophila species are traditionally used as models in investigations of phenotypic plasticity, although the majority of such research has been conducted with species of the subgenus Sophophora, primarily Drosophila melanogaster. In this study, we investigated the phenotypic plasticity of Drosophila cardini, a Neotropical species of the subgenus Drosophila, and focused on the wing size, wing shape, thorax length and wing: thorax ratio of lines that were collected in the Brazilian savanna and exposed to different temperatures during growth. All of the analyzed traits presented plasticity to temperature, and the reaction norms were similar to those previously found in other drosophilid species; in addition, the maximum values were consistent with the temperature variations at the collection sites. The specimens that emerged at low temperatures were larger and had more rounded wings compared with those that emerged at high temperatures, which were smaller and had narrower wings. We hypothesized that the differences observed in the shape of the wings might be associated with flight performance. Nevertheless, further investigation of the relationships among wing shape, wing loading and flight performance is required. Investigations on phenotypic plasticity using species with diverse ecologies should help us to better understand how this phenomenon operates in nature, and studies of this type must be encouraged.