Genetics Comprehensive Exam Seminar of Mitchell Roth

"Investigating Mechanisms of Root Infection and Sudden Death Syndrome Development in Glycine max Caused by Fusarium virguliforme" by Mitchell Roth

162 Food Safety & Toxicology Building; 2:00-3:00 PM
Committee Members:

Dr. Martin Chilvers, Dr. Frances Trail; Dr. Jonathon Walton; Dr. Brad Day; Dr. Maren Friesen

Abstract:

One of the top emerging threats to soybean production in the U.S. is sudden death syndrome (SDS) caused by the fungal pathogen, Fusarium virguliforme.  The soil-borne pathogen infects roots causing initial root rot symptoms, later followed by foliar symptoms marked by interveinal chlorosis and necrosis.  These foliar symptoms are caused by toxins and effector proteins that enter xylem during the root infection, since F. virguliforme remains in the roots throughout disease development.  These foliar symptoms can cause premature defoliation, pod drop, and up to 100% yield loss.  Two proteins, FvTox1 and FvNIS1, have been identified as important factors in foliar SDS development, but their modes of action remain unknown.  

Another common pest in soybean fields is the soybean cyst nematode (SCN).  Many studies indicate that SCN makes SDS symptoms occur sooner and become more severe than F. virguliforme can achieve alone.  A direct interaction has not been investigated, but may allow SCN to vector F. virguliforme into soybean roots via mechanical wounds.  Initially, F. virguliforme was thought to have a narrow host range, but it has recently shown the ability to colonize other common field crops and weeds, though development of classic SDS symptoms are inconsistent.  This proposal aims to elucidate the mechanisms by which F. virguliforme can enter soybean roots and identify the targets of FvTox1 and FvNIS1.  In addition, I will investigate alternate plant hosts for potential resistance to root infection and to foliar symptom development caused by these proteins.