Single-gene resolution of diversity-driven community overyielding

Abstract

In plant communities, diversity often increases community productivity and functioning, but the specific underlying drivers are difficult to identify. Most ecological theories attribute the positive diversity effects to complementary niches occupied by different species or genotypes. However, the type of niche complementarity often remains unclear, including how complementarity is expressed in terms of trait differences between plants. Here, we use a gene-centred approach to identify differences associated with positive diversity effects in mixtures of natural Arabidopsis thaliana genotypes. Using two orthogonal genetic mapping approaches, we found that between-plant allelic differences at the AtSUC8 locus contribute strongly to mixture overyielding. The corresponding gene encodes a proton-sucrose symporter and is expressed in root tissues. Genetic variation in AtSUC8 affected the biochemical activities of protein variants and resulted in different sensitivities of root growth to changes in substrate pH. We thus speculate that - in the particular case studied here - evolutionary divergence along an edaphic gradient resulted in the niche complementarity between genotypes that now drives overyielding in mixtures. Identifying such genes important for ecosystem functioning may ultimately allow the linking of ecological processes to evolutionary drivers, help to identify the traits underlying positive diversity effects, and facilitate the development of high-performing crop variety mixtures in agriculture.

Coadaptation of coexisting plants enhances productivity in an agricultural system

“…In the last years, breeding for more diverse crop systems (i.e. mixtures) has gained more attention (Bourke et al, 2021; Haug et al, 2021; Moore et al, 2022) and genes were identified which might be relevant for breeding in more diverse crop systems (Wuest et al, 2022; Wuest and Niklaus, 2018). Furthermore, a recent study found evidence for genetic and epigenetic evolution of monoculture and mixture ecotypes in grassland species (van Moorsel et al, 2019).…”