Fig. 6: Integrated model of root–microbiome–metabolite interactions associated with maize heterosis.
From: Rhizosheath inhabiting Massilia are linked to heterosis in roots of maize
In nitrogen-poor soil, hybrids typically develop larger rhizosheaths that provide a hub for microbial colonization, including enrichment of Massilia. Massilia is associated with increased lateral root density, which in turn enhances root–soil contact and nitrogen uptake. Flavonoid secretion, such as apigenin, attract Massilia to the rhizosphere, while Massilia inoculation can in turn influence flavonoid profiles, suggesting a reciprocal feedback loop. Together, rhizosheath size, root traits, and microbial associations correlate with improved growth and reduced N₂O emissions under stress. This model highlights rhizosheath formation as an integrative trait linking root development, exudation, and microbiome composition. Arrows indicate potential directions of interaction and feedback, but do not imply any established causality.
