The objectives of this research are to characterize Phymatotrichopsis root rot in alfalfa at the biological, chemical and genetic levels, with the long-term goal of developing resistant alfalfa varieties. We will approach the problem from the joint perspectives of the plant and the pathogen. Sequencing the genome of the pathogen (OU Advanced Genome Center) will provide access to the genetic blueprint that determines how this fungus causes disease and evades resistance mechanisms in so many plant species, as well as suggest molecular targets for disease control mechanisms. Developing a transformation system and other genetic resources for the fungus (OSU, Department of Plant Pathology) will enable us to delete specific fungal genes to test their involvement in causing disease. Breeding, selection and mutant screening strategies will identify lines of alfalfa and the closely related model legume Medicago truncatula with varying degrees of tolerance or susceptibility to the fungus (Noble Foundation Forage Improvement and Plant Biology Divisions). Application of genomic technology, metabolite profiling and antifungal screens (Noble Foundation Plant Biology and Forage Improvement Divisions) will determine how infected plants respond at the molecular level, and define chemical pathways and gene regulatory regions that can be used for engineering novel resistance mechanisms against the fungus.

The development of a cotton root rot resistant variety of alfalfa will greatly expand the alfalfa growing region of Oklahoma. This will allow Oklahoma farmers to produce a valuable crop which can be sold at a profit to a growing dairy industry in both western Oklahoma and Texas, as opposed to the present practice of importing alfalfa from other states.