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Helping plants fight off pathogens through chemical genomics


Through funding from the NSF-ChemGen Integrative Graduate Education and Research Trainee Program at University of California, Riverside, graduate student Mercedes Schroeder is identifying chemicals that have the potential to 1) reduce crop loss due to disease and 2) to diminish the use of traditional pesticides in agriculture.

Centuries of agricultural crop breeding to increase yield and improve desired traits have led to specialized crop plants. The plants have a minimal array of defense mechanisms needed to fight off the variety of disease-causing pathogens. In fact, 500,000 tons of crops were lost to diseases in the U.S. in 2010 alone (Pimentel, 2005, Development and Sustainability 7, 229). Schroeder’s research investigates the use of small molecule chemicals that can induce innate plant immune responses to pathogen attack. Such chemicals activate plant defense mechanisms at a molecular level. Her work builds on the chemical genomics studies previously performed in the lab of Associate Professor of Plant Cell Biology, Dr. Thomas Eulgem. The Eulgem lab’s screens for novel plant defense elicitors have identified over 100 candidate chemical compounds that induce immune responses in a model plant (Knoth et al., 2009; Plant Physiology, 150: 333). Schroeder tests the most robust of these chemicals to identify those that provide protection against fungal and bacterial attack in cowpea and tomato plants. This research involves the soil borne fungus Fusarium oxysporum and the bacterial pathogen Pseudomonas syringae, both of which are in-force damaging to crops. Cowpea and fungal assays are carried out in collaboration with Nematology Professor, Dr. Philip Roberts.

Chemical pesticides currently in use typically rely on direct antibiotic or biocidal activity to kill the pathogen, which often leads to toxic environmental side effects (Kessmann et al., 1994, Annual Review of Phytopathology 32, 439; Gilliom et al., 2007, Environmental Science & Technology 41, 3407). The goal of Schroeder’s project is to identify non-biocidal chemicals that will induce natural plant immune responses for the purpose of improving crop resistance to pathogens. New strategies of crop protection for tomato and cowpea are economically important for growers in California and around the world and may greatly benefit the health of consumers and the environment.

Address Goals

Through the advancement of chemical genetics compounds can be identified that produce a plant immune response to bolster crops against disease causing pathogens similar to a immunization helps prevent disease in animals. The compound can then be used to increase crop yield to aid in feeding the growing population.