Taxonomic and Phylogenomic Assessment Identifies Phytopathogenicity Potential of Stenotrophomonas maltophilia Complex

Stenotrophomonas maltophilia is a versatile bacterium found in plants, water, air, and even hospital settings. Deep taxono phylogenomics studies have revealed that S. maltophilia is a complex of several hidden species that are not differentiated using conventional approaches. In the last two decades, there have been increasing reports of S. maltophilia as a pathogen of diverse plants. Hence, proper taxonogenomic assessment of plant-pathogenic strains and species within the S. maltophilia complex (Smc) is required. In the present study, we formally propose a taxonomic amendment of Pseudomonas hibiscicola and P. beteli, reported as pathogens of Hibiscus rosa-sinensis and Betelvine (Piper betle) plants, respectively, as a misclassified member species of the Smc. Recently, a novel species of the genus, S. cyclobalanopsidis, was reported as a leaf spot pathogen of the oak tree genus Cyclobalanopsis. Interestingly, our investigation also revealed S. cyclobalanopsidis as another plant-pathogenic member species of the Smc lineage. In addition, we provide deep phylo-taxonogenomic evidence that S. maltophilia strain JZL8, reported as a plant pathogen, is a misclassified strain of S. geniculata, making it the fourth member species of the Smc harboring plant-pathogenic strains. Therefore, a proper taxonomic assessment of plant-pathogenic strains and species from the Smc is required for further systematic studies and management.