Abstract:[Background] Pseudomonas donghuensis HYS is a high-siderophore-yielding strain isolated and identified by our laboratory from the Wuhan East Lake. HYS has strong toxicity to Caenorhabditis elegans. Previous studies have found that insertions in the argS gene in HYS can significantly reduce its toxicity to C. elegans. [Objective] To explore the function of argS gene and how it affects bacterial toxicity, and to provide a theoretical basis for further study on the mechanism of HYS toxicity. [Methods] The biological function of argS gene and the relationship between the arginine succinyltransferase (AST) pathway and bacterial toxicity were investigated with bioinformatics comparison, genetic analysis, physiological assays, and biochemical experiments. [Results] The argS gene in HYS encodes a protein that shares 88% similarity to the arginine succinyltransferase β subunit in Pseudomonas aeruginosa. The deletion of argS prevented the HYS strain from using arginine as the sole carbon source for growth. Deletion strains of key genes in arginine decarboxylase (ADC) pathway, arginine dehydrogenase (ADH) pathway and arginine deiminase (ADI) pathway could normally use arginine as the sole carbon source and had no significantly attenuated effect on the toxicity to C. elegans. Added arginine to these strains significantly attenuates the toxicity, and decreases their ability in producing siderophores. [Conclusion] AST pathway in Pseudomonas donghuensis HYS can affect the toxicity to C. elegans by affecting the synthesis of the siderophores. This study lays the foundation for further studies into the mechanism of arginine metabolism and pathogenicity in Pseudomonas.
