Identification, Characterization, and Impact of Pathogenic Fusarium Species on Switchgrass (Panicum virgatum L.)

M.S. Research Proposal Seminar Summary Kristie Mantooth February 2013

Biofuel is a promising source of alternative fuel that is the focus of much current research. Switchgrass (Panicum virgatum L.) is being considered as a cellulosic feedstock for biofuel. This warm-season, perennial grass is native to North America. It is seed propagated and can be managed with conventional farming equipment (Lewandowski 2003, McLaughlin 2002) with low agricultural inputs (Bouton 2008). This species is a relatively new crop that has only recently been grown in large acreage monoculture (Bouton 2008). There is limited knowledge of switchgrass pathogens and it is expected that an increase in disease reports will accompany the increase in land dedicated to this promising perennial grass.

A recent study in our lab (Vu 2011) found more than 2,000 fungal isolates on switchgrass seeds. Species of Fusarium were among the most common pathogens found. The USDA fungal database (Farr and Rossman 2013) includes 146 fungal isolates recovered from switchgrass, including ten Fusarium species. Species of Fusarium are known pathogens of important crops such as corn, rice, and wheat and some produce toxins that may be harmful to animals. Controlling these pathogens should be included in management practices of switchgrass grown for biofuel.

The purpose of this proposed research is to identify and characterize the impacts of Fusarium species on switchgrass. The objectives are 1) identify and characterize Fusarium isolates previously collected from switchgrass seeds produced outside Tennessee 2) determine pathogenicity and virulence of Fusarium species on switchgrass 3) determine impact of selected virulent Fusarium species on stand establishment, plant health and development, and biomass 4) determine pathogenicity and virulence of the most virulent Fusarium species from switchgrass on other hosts and 5) identify seedborne pathogens of switchgrass from fields in the southeast.

References:

Lewandowski, I., et al. (2003). The development and current status of perennial rhizomatous grasses as energy crops in the US and Europe. Biomass and Bioenergy 25 (4): 335–361.

McLaughlin, S. B., et al. (2002). High-value renewable energy from prairie grasses. Environmental Science & Technology 36 (10): 2122–2129.

Bouton, J. (2008). Improvement of switchgrass as a bioenergy crop. Pages 295-308 in: Genetic Improvement of Bioenergy Crops. W. Vermeriss, ed. Springer, New York.

Farr, D.F., & Rossman, A.Y. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved January 30, 2013, from http://nt.ars-grin.gov/fungaldatabases/.

Vu, A. L. (2011). Identifying pathogens of switchgrass and investigating antimicrobial activity of switchgrass-derived extractives. M.S. thesis, The University of Tennessee, Knoxville. 82 pp.