It is possible that PAMPs from B. pseudomallei and B. thailandensis are able to trigger an effective basal defence from rice to halt bacterial colonization, a common means of plant resistance against non-adapted microorganisms [24–26]. Another
intriguing possibility is that compounds secreted by rice plants may inhibit the growth of B. thailandensis and B. pseudomallei. The presence of secondary metabolites induced by B. pseudomallei infection in plants with differential susceptibility to disease could reveal novel anti-infective compounds against melioidosis to counter the problem of extensive antibiotic resistance in this bacterium. Thus, B. pseudomallei joins a growing list of human pathogens which have been found to be able to infect plants , the first of which to be described was P. aeruginosa . The plant host model has been used to perform large BI 2536 clinical trial scale screening of a library of P. aeruginosa mutants to identify novel virulence factors  as some virulence factors encoded by genes such as toxA, plcS and gacA were shown to be important for bacterial pathogenesis in EX 527 order both plants and animals . Given the evidence that B. pseudomallei T3SS3 may be capable of interacting with both mammalian and plant hosts, and the ability of B. pseudomallei to infect
tomato, one could develop susceptible plants as alternative host models for large scale Interleukin-2 receptor screening of B. pseudomallei mutants to aid in novel virulence factor discovery, similar to what had been done for P. aeruginosa. Previously, B. pseudomallei has been shown to infect C. elegans  and Acanthamoeba species  and C. elegans could be used as an alternative host model for large
scale screening and identification of B. pseudomallei virulence factors . Our current finding reveals the additional versatility of B. pseudomallei as a pathogen and further research would likely uncover novel bacterial mechanisms capable of interacting with its varied hosts. Much more work is needed to define the susceptibility of various plant species to B. pseudomallei to find a suitable plant host for virulence factor discovery. It remains to be seen if B. pseudomallei is a natural pathogen for crops such as tomatoes. Conclusions In summary, we identified B. pseudomallei as a plant pathogen capable of causing disease in tomato but not rice plants. B. pseudomallei T3SS1 and T3SS2 contribute significantly to disease whereas T3SS3 plays a more minor role. Although the significance of B. pseudomallei as a natural plant pathogen in the environment is unknown, one could postulate that certain plants may serve as a reservoir for the bacteria. Since B. pseudomallei is classified as a bioterrorism agent by the US Centers for Disease Control and Prevention http://www.cdc.gov/od/sap, our findings indicate that it may be necessary to re-evaluate Selleckchem MK5108 whether B.