Rhizospheric life of Salmonella requires flagella-driven motility and EPS-mediated attachment to organic matter and enables cross-kingdom invasion

Abstract

Salmonella is an established pathogen of the members of the kingdom Animalia. Reports indicate that the association of Salmonella with fresh, edible plant products occurs at the pre-harvest state, i.e. in the field. In this study, we follow the interaction of Salmonella Typhimurium with the model plant Arabidopsis thaliana to understand the process of migration in soil. Plant factors like root exudates serve as chemo-attractants. Our ex situ experiments allowed us to track Salmonella from its free-living state to the endophytic state. We found that genes encoding two-component systems and proteins producing extracellular polymeric substances are essential for Salmonella to adhere to the soil and roots. To understand the trans-kingdom flow of Salmonella, we fed the contaminated plants to mice and observed that it invades and colonizes liver and spleen. To complete the disease cycle, we re-established the infection in plant by mixing the potting mixture with the fecal matter collected from the diseased animals. Our experiments revealed a cross-kingdom invasion by the pathogen via passage through a murine intermediate, a mechanism for its persistence in the soil and invasion in a non-canonical host. These results form a basis to break the life-cycle of Salmonella before it reaches its animal host and thus reduce Salmonella contamination of food products.

Effect of Environmental Temperatures on Proteome Composition of Salmonella enterica Serovar Typhimurium

“…In addition to temperature-dependent changes in metabolism and stress response, the proteomic analyses in this study indicate the temperature-dependent synthesis of flagellar and chemotaxis proteins enabling a directed motility and is of crucial importance for Salmonella virulence. Several studies revealed the involvement of flagella-mediated motility in Salmonella infection of mammalian and plant hosts ( 59 , 60 ).…”

Lysinibacillus macroides‐mediated control of cellulose‐producing morphotype of Salmonella

“…Swim agar plates were prepared with 0.3% (w/v) agar. Overnight cultures grown in LB were spotted on the swim agar plates and incubated at 26 °C for different time points 5 . The images of the plates were taken with an Olympus STYLUS VH520 camera.…”

“…Overnight cultures grown in LB were spotted on the swim agar plates and incubated at 26 °C for different time points. 5 The images of the plates were taken with an Olympus STYLUS VH520 camera. Strain ΔfliC/fljB was used as negative control (without flagella) and the strains ΔcsgD and ΔbcsA were used as positive controls (hypermotile).…”

“…Salmonella enters the field via the use of contaminated irrigation water 2 and forms a stable niche on the soil inorganic and organic matter in the form of biofilm. 5 Crops raised in such contaminated soil are known to be colonized by Salmonella irrespective of the species of the plant. 6 The presence of Salmonella in different plant organs like root, 7 leaves 8 and fruit 9 decipher its natural ability to invade and colonize the host.…”

“…This pre‐harvest contamination of food products is one of the greatest concerns in food safety. Salmonella enters the field via the use of contaminated irrigation water 2 and forms a stable niche on the soil inorganic and organic matter in the form of biofilm 5 . Crops raised in such contaminated soil are known to be colonized by Salmonella irrespective of the species of the plant 6 .…”