Format: ORAL

Javier Puy1, Vit Latzel2, Carlos P. Carmona3, Michael Thieme4, Etienne Bucher5, Lars Gtzenberger2,6, Francesco de Bello6,7

1. Estación Biológica de Doñana, CSIC, Sevilla, Spain. 2. Institute of Botany, Czech Academy of Sciences, Pruhonice, Czech Republic. 3. Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia. 4. Department of Plant and Microbial Biology, University of Zürich, Zürich, Switzerland. 5. Crop Genome Dynamics Group, Nyon, Switzerland. 6. Department of Botany, University of South Bohemia, Ceské Budejovice, Czech Republic. 7. CIDE-UV-CSIC, Centro de Investigaciones sobre Desertificación, Valencia, Spain.

The observed positive effect of diversity on ecosystem functioning, explained by mechanisms of trait diversity, has rarely been assessed within populations. However intraspecific phenotypic variability should theoretically cause similar biodiversity effects. Intraspecific trait variation could stem both from underlying genetic diversity and non-genetic mechanisms such as plasticity in response to environmental cues. This plasticity can potentially last multiple generations and can derive, for example, from epigenetic modifications or mobilization of transposable elements. Using Arabidopsis thaliana as a proof-of-concept model, our work has been on unravelling the effect of phenotypic diversity generated by 1) heritable plasticity and 2) transposable elements on coexistence, population productivity, and resistance to stress, as well as on comparing their magnitude with the effect of genetic diversity. Across two glasshouse experiments, three different types of Arabidopsis thaliana populations were established: one type with differing levels of genetic diversity, another one with a different mixture of individuals that differed in their ONSEN retrotransposon insertions, and a last one, genetically uniform but with varying diversity levels of the parental environments (parents grown in the same or different environments). In all populations, we tested whether the increasing diversity increased the phenotypic diversity of populations and enhanced their functioning under different conditions. As expected, both heritable plasticity and transposable elements created differentiation in ecologically important traits connected to different axes of the plant economics spectrum. Such increased phenotypic diversity ameliorated the negative effect of competition between coexisting individuals and enhanced population productivity and stress resistance; and interestingly, by a similar magnitude as genetic diversity did. Our results highlight the ecological relevance of unexplored sources of phenotypic variability because as other sources of biodiversity, they could similarly affect ecosystem and population functioning.