<b>Volatile Signaling Positively Integrates Bulk Soil with Rhizosphere-Plant Nexus</b>

Plant‒microbiome interactions can extend over longer distances in the soil matrix via VOCs, which could potentially link topologically disconnected microbes with plants and their associated rhizobiomes. Here, we show that the plant, rhizobiome, and bulk soil microbiome are interconnected and affected by VOC-mediated long-distance signaling, forming a cohesive underground ecosystem with an extended spatial range of plant‒microbe interactions. The reciprocal VOC signaling between the rhizosphere and bulk soil significantly but differentially modulates their microbiome composition, functions, and VOC profiles, fortifies the plant-microbe partnership, and ultimately improves nutrient acquisition efficiency and plant growth. These effects were reduced and varied when VOC signaling from the bulk soil or the rhizosphere was reduced, resulting in distinct microbiome and VOC profiles.