Pantoea and Plants: Friends, Foes, and Everything in Between

The genus Pantoea includes species that occupy diverse ecological niches and exhibit significant functional versatility. Historically associated with taxonomic ambiguity within the Enterobacter agglomerans/Erwinia herbicola complex, the advent of genome-based approaches has substantially refined species delineation and evolutionary relationships within the genus. Pantoea species are ubiquitous, occupying environmental, plant, insect, and clinical habitats, where they function as mutualists, commensals, or opportunistic pathogens. In plant-associated interactions, they contribute to growth promotion, stress tolerance, and biocontrol while also emerging as significant phytopathogens with expanding host ranges and geographical distributions. Their pathogenicity involves multiple mechanisms, including secretion systems, quorum sensing, exopolysaccharide production, and toxin synthesis. Strains within the same species may exhibit different lifestyles, complicating efforts to predict ecological function or assess biosafety. This review synthesizes current knowledge on the taxonomy, ecology, and functional roles of Pantoea, with an emphasis on insights gained from taxogenomics. Unlike previous reviews, this synthesis integrates taxogenomic advances with ecological and functional data to critically examine lifestyle plasticity within Pantoea and its implications for biosafety and application. It highlights the challenges associated with distinguishing beneficial from pathogenic strains and emphasizes the need for integrative approaches combining genomics, functional assays, and host interaction studies. Understanding the ecological and genetic determinants causing lifestyle plasticity in Pantoea is essential for exploiting its beneficial potential while reducing risks to agriculture and human health.