Physiological Integration of Nutrient Exchange, Hormone Signaling and Multi-Stress Crosstalk in Plant-Rhizobacteria Symbiosis

Plant growth-promoting rhizobacteria (PGPR) establish intricate symbiotic associations with host plants, fundamentally influencing nutrient acquisition, hormonal balance, and stress resilience. Unlike mycorrhizal symbioses, which operate through fungal hyphal networks extending the root system, PGPR act at the root surface and rhizosphere interface, where root-derived exudates shape bacterial colonization while bacterial signals reprogram plant developmental and defensive pathways. Key processes include the modulation of root architecture by bacterially produced phytohormones, the enhancement of nitrogen and phosphorus uptake through bacterium-specific exchange mechanisms (e.g., siderophore-mediated iron delivery, ACC deaminase activity), and the priming of systemic tolerance against abiotic and biotic challenges. Despite significant progress, these physiological phenomena are frequently studied in isolation, limiting a holistic understanding of how nutrient exchange, hormone crosstalk, and multi-stress responses are coordinated at the whole-plant level during rhizobacterial symbiosis specifically.A major gap remains in our integrated understanding of how PGPR, as distinct from mycorrhizal fungi, simultaneously influence nutrient dynamics, hormonal networks, and stress physiology within the host plant. Individual mechanisms, such as auxin-mediated root remodeling or phosphate solubilization by rhizobacteria, are well catalogued, yet their interplay under fluctuating environmental conditions is poorly resolved. This Research Topic aims to bridge that gap by bringing together mechanistic studies that examine the physiological intersections among nutrient exchange, hormone modulation, and multi-stress crosstalk specifically in plant-PGPR symbioses. We encourage contributions that address how a single rhizobacterial strain or consortium can coordinate these processes, how plant hormonal status feeds back onto nutrient transporter activity and stress responses in a bacterial (non-mycorrhizal) symbiotic context, and how the rhizosphere chemical environment integrates these signals. By focusing strictly on the physiological and mechanistic level of bacterial symbiosis, we seek to construct a more unified framework that explains how PGPR confer systemic benefits, ultimately providing a solid foundation for sustainable crop management.This Research Topic will concentrate exclusively on the physiological mechanisms underpinning plant-PGPR (rhizobacterial) interactions; studies centered on arbuscular mycorrhizal or other fungal symbioses fall outside its scope. We welcome submissions addressing, but not limited to:• Mechanistic dissection of nutrient exchange (nitrogen, phosphorus, iron) mediated by PGPR at the root-rhizosphere interface.• PGPR-driven hormonal modulation of root development and symbiotic efficiency (auxins, cytokinins, gibberellins, strigolactones, ACC deaminase activity).• Physiological crosstalk among abiotic stress responses, biotic defense, and nutrient signaling during rhizobacterial colonization.• Root exudate chemistry and its role in shaping specific PGPR-host physiological dialogues.• Multi-stress physiological integration: how plants prioritize or balance nutrient acquisition, growth, and defense under combined stresses in the presence of PGPR. Topic editors: Zhen Wang, Anjali Chandrol Solanki, Lv Su Source: https://www.frontiersin.org/research-topics/84890/physiological-integration-of-nutrient-exchange-hormone-signaling-and-multi-stress-crosstalk-in-plant-rhizobacteria-symbiosis