A highly conserved ABCG transporter mediates root-soil cohesion in Arabidopsis

Identifying plant molecular mechanisms that mediate root-substrate interactions might offer potential solutions to soil erosion, especially in crop fields, where agricultural practices lead to soil loss. Mutants of the Arabidopsis (Arabidopsis thaliana) ATP-Binding Cassette G 43 (ABCG43) transporter gene show enhanced root-substrate cohesion, even though their root micro- and macro-structures are similar to those of wild-type Arabidopsis. We used genetic, biochemical, and functional methods to characterize the substrate-binding effects of changes in ABCG43 expression, including differences in exudate composition, and phylogenetic analyses to explore the evolutionary history of ABCG43 in land plants. Exudates from roots of the abcg43 mutant bound more soil and growing medium, and there were significant differences in abcg43 root exudate composition compared with the wild type. These results suggest that ABCG43 normally functions to mediate root exudates that affect root-substrate cohesion. Phylogenetic analysis showed that ABCG43 is highly conserved in plants, including in agriculturally important crop species. These results provide evidence that ABCG43 is a promising molecular target for developing crop plants with enhanced root-soil cohesion.