Esther Chen

Assistant Professor of Biology

Department of Biological Science

Ph.D., Massachusetts Institute of Technology, 2003

• Teaches: Microbiology
• Office: MH- 207C
• Telephone: (714) 278-2543
• Laboratory: DBH-121
• Lab Telephone: (714) 278-5268
• Fax: (714) 278-3426
• echen@fullerton.edu
• http://biology.fullerton.edu/echen/
• Personal Pages [not yet]

Research Interests

I am interested in the molecular biology of an agriculturally important symbiosis between the bacterium Sinorhizobium meliloti and its plant host alfalfa. In this mutualistic symbiosis, the bacteria supply usable, "fixed" nitrogen to the plant, while the plant supplies carbon sources to the bacteria. The plant and the bacteria communicate by means of chemical signals: flavonoids from the plant and Nod factor from the bacteria. Nod factor induces localized cell proliferation in the root, forming a new organ called the root nodule. The S. meliloti bacteria then invade plant cells in the root nodule. Because the establishment of this symbiosis requires the bacteria to invade and survive inside eukaryotic cells, this symbiosis is also an excellent model for the pathogenic microbe-host interactions exhibited by Brucella bacteria during Brucellosis, a serious human and animal disease commonly found in developing countries. At present, my research focus is the S. meliloti ExoS-ChvI two-component signaling pathway required for symbiosis. Study of the upstream and downstream effectors of ExoS-ChvI will provide insight into the underlying mechanisms important for both symbiotic and pathogenic microbe-host interactions.