Microbial Regulation of Plant Stress Signaling: From Ethylene and Hormonal Control to Field-Resilient Crops

Microbial regulation of plant stress signaling is emerging as a decisive lever in how crops withstand a changing climate. As drought, salinity, flooding, heat, and metal contamination become more frequent and more likely to occur together, plants respond through hormonal networks in which ethylene has a central role. The hormone governs germination, root development, nodulation, and senescence, yet its sustained accumulation under stress restricts root elongation, limits water and nutrient acquisition, and constrains yield. Plant-associated microorganisms intervene directly at this point: rhizobacteria and endophytes producing 1-aminocyclopropane-1-carboxylate (ACC) deaminase cleave the immediate precursor of ethylene and lower its stress-induced accumulation, while phytohormone production, osmolyte and exopolysaccharide synthesis, antioxidant activity, volatile signaling, and nutrient solubilization act on the same physiological outcome through complementary routes.Considerable progress has been made in isolating and characterizing such microorganisms, and controlled experiments consistently report improved growth and stress tolerance across cereals, legumes, and horticultural crops. However, the translation of these results into agriculture remains inconsistent. Effects that are robust under greenhouse conditions frequently diminish in the field, and the reasons are rarely resolved: soil properties, resident microbial communities, cultivar genotype, inoculum formulation, and colonization dynamics all modulate the outcome, and relatively few studies test the proposed mechanism rather than inferring it from a growth response. Research on plant hormonal signaling and on the microbial ecology of the rhizosphere has also advanced largely in parallel, which limits the ability to explain when and why microbial intervention succeeds.This Research Topic aims to establish a systems-level understanding of how plant-associated microorganisms regulate hormonal and physiological stress responses in crops, and how that regulation determines performance under realistic growing conditions. The objective is to connect microbial genetic and functional traits with plant signaling and physiology, community behavior in the rhizosphere and endosphere, and agronomic outcomes across soils, cultivars, and climates. By bringing together mechanistic, ecological, and applied perspectives, the collection seeks to identify the conditions under which microbial intervention delivers reliable gains in crop performance. The ultimate goal is to support the design, validation, and deployment of microbial solutions for climate-resilient and sustainable crop production.The boundaries of this Research Topic extend from the biochemistry of ACC deaminase and hormonal cross-talk to the formulation, delivery, and field evaluation of microbial inoculants in stress-prone production systems. Submissions are especially encouraged if they combine mechanistic validation with ecological or agronomic evidence. To gather further insights, we welcome articles addressing, but not limited to, the following themes:• ACC deaminase, ethylene modulation, and microbial mechanisms that regulate plant hormone balance under stress• Microbial modulation of plant physiological responses to drought, salinity, flooding, heat, and metal stress• Cross-talk between ethylene, auxin, abscisic acid, reactive oxygen species, and nutrient signaling• Trait-based selection, screening, and functional validation of stress-tolerant plant-beneficial bacteria and fungi• Endophytes, rhizobacteria, and mycorrhizal partners in crop stress adaptation• Design and functional validation of microbial consortia for stress-resilient crops• Biocontrol and induced systemic resistance under combined abiotic and biotic stress• Multi-omics, transcriptomic, and physiological approaches to plant–microbe stress mechanisms• Greenhouse, field, and multi-location assessment of microbial performance across soils, cultivars, and seasons• Bioformulation, delivery, colonization, and persistence of stress-tolerant inoculants• Links between microbial stress regulation, soil health, and greenhouse gas emissions in agroecosystemsWe welcome Original Research, Review, Mini Review, Methods, Perspective, Hypothesis and Theory, and Technology and Code articles. Topic editors: Gustavo Santoyo, Ma. del Carmen Orozco-Mosqueda Source: https://www.frontiersin.org/research-topics/84871/microbial-regulation-of-plant-stress-signaling-from-ethylene-and-hormonal-control-to-field-resilient-crops