Abstract
Plants are daily challenged by multiple abiotic and biotic stresses. A major biotic constraint corresponds to competition with other plant species. Although plants simultaneously interact with multiple neighboring species throughout their life cycle, there is still very limited information about the genetics of the competitive response in the context of plurispecific interactions. Using a local mapping population of Arabidopsis thaliana, we set up a genome wide association study (GWAS) to estimate the extent of genetic variation of competitive response in 12 plant species assemblages, based on three competitor species (Poa annua, Stellaria media, and Veronica arvensis). Based on five phenotypic traits, we detected strong crossing reaction norms not only between the three bispecific neighborhoods but also among the plurispecific neighborhoods. The genetic architecture of competitive response was highly dependent on the identity and the relative abundance of the neighboring species. In addition, most of the enriched biological processes underlying competitive responses largely differ among neighborhoods. While the RNA related processes might confer a broad range response toolkit for multiple traits in diverse neighborhoods, some processes, such as signaling and transport, might play a specific role in particular assemblages. Altogether, our results suggest that plants can integrate and respond to different species assemblages depending on the identity and number of each neighboring species, through a large range of candidate genes associated with diverse and unexpected processes leading to developmental and stress responses.
Highlights
Plant-plant interactions are recognized as a major factor mediating the plant community structure, diversity, and dynamics (Tilman, 1985; Goldberg and Barton, 1992; Chesson, 2000; Martorell and Freckleton, 2014)
We extended the study from Baron et al (2015) by setting up a genome wide association study (GWAS) to compare the genetic architecture of competitive response of A. thaliana between bispecific and plurispecific neighborhoods
Significant genetic variation was found across the 12 treatments (Figure 1) for the five phenotypic traits scored on the focal A. thaliana plants (Table 1 and Supplementary Table 1)
Summary
Plant-plant interactions are recognized as a major factor mediating the plant community structure, diversity, and dynamics (Tilman, 1985; Goldberg and Barton, 1992; Chesson, 2000; Martorell and Freckleton, 2014). Deciphering the genetic and molecular bases of plant-plant interactions appears fundamental to predicting the evolutionary dynamics of plant communities in. The Genetics of Plurispecific Interactions ecological time (Pierik et al, 2013; Frachon et al, 2017). This is especially relevant in the context of current anthropogenic modifications of plant assemblages, which may in part result from the intertwined effect of increased plant biomass and reduced plant diversity under climate warming (Baldwin et al, 2014) or from the native species having different geographical range shifts under climate change (Bachelet et al, 2001; Gilman et al, 2010; Singer et al, 2013). In the context of complementarity in using resources, optimizing species assemblages in the crops may be facilitated by the understanding of the genetics underlying overyielding (Litrico and Violle, 2015; Pakeman et al, 2015; Weiner et al, 2017)
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