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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Molecular Plant Pathology Laboratory » Research » Publications at this Location » Publication #321391
Title: Gene expression profiling in viable but not culturable (VBNC) cells of Pseudomonas syringae pv syringae

Author
item POSTNIKOVA, OLGA - Academy Of Science Of Russia
item Shao, Jonathan
item Mock, Norton
item Baker, Con
item Nemchinov, Lev

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2015
Publication Date: 12/18/2015
Citation: Postnikova, O., Shao, J.Y., Mock, N.M., Baker, C.J., Nemchinov, L.G. 2015. Gene expression profiling in viable but not culturable (VBNC) cells of Pseudomonas syringae pv syringae. Frontiers in Microbiology. 6:1419.

Interpretive Summary: Our objective is related to understanding molecular mechanisms of stress tolerance in alfalfa, the most widely grown forage crop in the world. Alfalfa yield losses from bacterial stem blight pathogen Pseudomonas syringae pv. syringae can be as high as 50% of the first harvest. More information on the physiological and molecular events of the host inhibitory environment on the pathogen is needed to develop resistant cultivars. In this work we performed a large scale gene expression analysis of Pseudomonas syringae pv. syringae treated by acetosyringone, a compound that is induced in plants in response to bacteria. The findings offer insight into what might happen in the plant when bacterial pathogens are first encountered and host defense responses are triggered. The acquired knowledge will improve our understanding of the molecular mechanisms of stress tolerance.

Technical Abstract: Gram-negative bacterium Pseudomonas syringae infects diverse crop plants and comprises at least 50 different pathovar strains with different host ranges. One of our objectives is related to understanding molecular mechanisms of stress tolerance in alfalfa, the most widely grown forage crop in the world. It was reported that alfalfa yield losses from the bacterial stem blight pathogen Pseudomonas syringae pv. syringae can be as high as 50% of the first harvest. More information on the physiological and molecular events of the host inhibitory environment on the pathogen is needed to develop resistant cultivars. Recently, we reported an in vitro model system that mimics the redox pulse associated with the oxidative burst in plant cells inoculated with Pseudomonas syringae pv. syringae. Using this system, we demonstrated that oxidation of acetosyringone, a major extracellular phenolic compound induced in some plants in response to bacteria, rendered P.s. pv. syringae to a “viable but non-culturable” (VBNC) state. Since production of reactive oxygen species often plays a key role in triggering a hypersensitive response in the resistant host plants, identifying the bacterial genes affected by these conditions dox and involved in bacterial survival strategy may shed light on the ability of the pathogen to cause disease. Here we performed a large scale transcriptome profiling of P.s.pv. syringae in the VBNC state induced by acetosyringone treatment and identified bacterial genes and pathways presumably associated with this condition. The findings offer insight into what events occur when bacterial pathogens are first encountered and host defense responses are triggered. The acquired knowledge will improve our understanding of the molecular mechanisms of stress tolerance. We believe that this is the first work on global gene expression profiling of VBNC cells in plant bacteria.