Following the Tracks of an Extremely Adaptive Bacterium
Genomic analysis of Pseudomonas syringae uncovers unique natural products with potential applications in agriculture and medicine
A recent interdisciplinary study has uncovered how the plant pathogen Pseudomonas syringae may become a valuable source of bioactive compounds. Through a comprehensive genomic and chemical investigation, researchers have identified two new families of natural products—syrilipamides and secimides—with selective activity against fungi and amoebae, opening new perspectives for biotechnology and pharmaceutical development.
The research, conducted by scientists from the Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute (Leibniz-HKI) and the University of Jena, illustrates how this soil-dwelling bacterium produces a broad range of molecules that likely support its survival and ecological competitiveness. While P. syringae is notorious for its role in plant disease and agricultural loss, it is also a prolific producer of natural products that could be harnessed for beneficial purposes.
Diving into the Pangenome
The team analyzed the genomes of 18 representative P. syringae strains using cutting-edge bioinformatics tools. This pangenome approach revealed an astonishing 231 biosynthetic gene clusters—stretches of DNA encoding the enzymes needed to produce natural products. Notably, many of these clusters encode nonribosomal peptide synthetases (NRPS), a class of enzymes known to synthesize molecules with antibiotic or antimicrobial properties.
By integrating genome mining, chemical structure elucidation, and biological activity assays, the researchers discovered and characterized two novel molecular families: syrilipamides and secimides. Both are small molecules produced by various P. syringae strains and exhibit potent toxicity against amoebae and fungi—microbial predators and competitors in the soil environment.
Chlorination for Complexity
Adding to the significance of this work, the team also discovered a previously unknown enzyme, dubbed SecA, which is capable of chlorinating organic compounds. "SecA adds chlorine atoms to specific molecules, increasing their chemical complexity and enhancing their biological activity," explains Shuaibing Zhang, first author of the study. Project leader Prof. Pierre Stallforth, Principal Investigator in the Cluster of Excellence "Balance of the Microverse", head of department at Leibniz-HKI, and professor at the University of Jena, adds: “Chlorinated natural products are of great interest in drug discovery and could inform the development of new antibiotics or crop protection agents.”
From Soil to Solutions
Although the immediate aim of the study was to better understand the ecological role of these compounds, their selective activity offers promising applications in agriculture and medicine. For P. syringae, these natural products likely serve as weapons against microbial threats and as tools for niche adaptation. The findings shed light on the complex chemical interactions that underpin microbial ecosystems and contribute to the broader mission of the Cluster of Excellence "Balance of the Microverse": understanding how microorganisms shape and respond to their environments.
This research was supported by the Werner Siemens Foundation, the Leibniz Association, and the German Research Foundation (DFG) through the Collaborative Research Center ChemBioSys and the Cluster of Excellence Balance of the Microverse.
Original publication
Zhang S, Huang Y, Nachawati R, Huber P, Walther G, Gregor L, Vilotijević I, Stallforth P (2025) Pangenome Analysis of the Plant Pathogen Pseudomonas syringae Reveals Unique Natural Products for Niche Adaptation. Angew Chem Int Ed 64 (25), e202503679
https://doi.org/10.1002/anie.202503679