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ARS Home » Pacific West Area » Albany, California » Plant Gene Expression Center » Research » Publications at this Location » Publication #354174

Research Project: Molecular Mechanisms of Plant Defense Signaling

Location: Plant Gene Expression Center

Title: Soil mixture composition alters Arabidopsis susceptibility to Pseudomonas syringae infection

item HASSAN, JANA - University Of California
item DE LA TORRE-ROCHE, ROBERTO - Connecticut Agricultural Experiment Station
item WHITE, JASON - Connecticut Agricultural Experiment Station
item Lewis, Jennifer

Submitted to: Plant Direct
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2018
Publication Date: 2/19/2018
Citation: Hassan, J.A., De La Torre-Roche, R., White, J., Lewis, J.D. 2018. Soil mixture composition alters Arabidopsis susceptibility to Pseudomonas syringae infection. Plant Direct. 2:1-13.

Interpretive Summary: Successful infection of a plant by a pathogen requires a suitable environment. Pseudomonas syringae is a bacterial pathogen that infects a wide range of plant species. We investigated the role of the soil environment in influencing the ability of the plant to protect itself from disease. Although P. syringae infects above-ground parts of the plant, we found that the soil environment in which the plants were grown affected the resistance of the plants. Arabidopsis plants grown in commercial soil enriched with silicon were more resistant to bacterial infection than plants grown in commercial soil lacking silicon. However silicon did not appear to directly cause enhanced resistance. Instead the silicon-enriched soil appears to have other characteristics that enhance plant resistance to infection. This work points to the importance of soil composition in helping to promote plant resistance to infection.

Technical Abstract: Pseudomonas syringae is a Gram-negative bacterial pathogen that causes disease on more than 100 different plant species, including the model plant Arabidopsis thaliana. Dissection of the Arabidopsis thaliana-Pseudomonas syringae pathosystem has identified many factors that contribute to successful infection or immunity, including the genetics of the host, the genetics of the pathogen, and the environment. Environmental factors that contribute to a successful interaction can include temperature, light and the circadian clock, as well as the soil environment. Since silicon-amended Resilience soil is advertised to enhance plant health, we sought to examine the extent to which this soil might affect the behavior of the A. thaliana-P. syringae model pathosystem, and to characterize the mechanisms through which these effects may occur. We found that plants grown in Si-amended Resilience soil displayed enhanced resistance to bacteria compared to plants grown in non-Si-amended Sunshine soil, and salicylic acid biosynthesis and signaling were not required for resistance. Although silicon has been shown to contribute to broad spectrum resistance, our data indicate that silicon is not the direct cause of enhanced resistance, and that the Si-amended Resilience soil has additional properties that modulate plant resistance. Our work demonstrates the importance of environmental factors such as soil in modulating interactions between the plant and foliar pathogens, and highlights the significance of careful annotation of the environmental conditions under which plant-pathogen interactions are studied.