Chemical Elicitors Induce Plant Defense Responses

Leaves normally release low levels of volatile chemicals, however when a plant is damaged by herbivorous insects, many more volatiles are released.  These volatiles attract both parasitic and predatory insects that are natural enemies of herbivores.  Activation of such defense responses by plants can be triggered by non-volatile elicitors that make direct contact with plant tissue or by volatile chemicals that are air-borne in their transmission.  An example of a non-volatile elicitor is volicitin (N-[17-hydroxylinolenoyl]-L glutamine) isolated from the regurgitant of the agricultural pest beet armyworm and activate in triggering the emissions of volatile organic compounds when in contact with damaged corn leaves.   Volatile components such as methyl jasmonate and certain C₆ alcohols can also be released from and trigger defense responses in plants.  We are interested in characterizing the initial biochemical responses that are activated in model plant systems in response to chemical elicitors.                                                                         

Bacterial Volatile Chemicals Trigger Plant Growth Promotion

Plant growth-promoting rhizobacteria are a wide range of root-colonizing bacteria with the capacity to enhance plant growth by increasing seed germination, plant weight, and crop yields.  Little has been reported as to the role of microbial volatiles in regulating plant growth and development, although we have recently observed that certain bacterial volatiles can serve as agents for triggering growth promotion in Arabidopsis.  We are interested in identifying genes that are up or down regulated by exposure to bacterial volatile emissions as a way to probe the signal transduction sequence responsible for enhanced plant growth with exposure to bacterial volatiles and chemical analogues.