Gary Yuen


Gary Yuen
Professor

  • PH.D., University of California - Berkeley, 1984

Being a staunch supporter of “green” technology, one of my dreams is to see the day when biological control becomes a mainstream strategy for managing pests and plant diseases. I have been working towards that dream in my own research, pitting biocontrol agent against a wide range of foliar-infecting and soilborne fungal pathogens and plant parasitic nematodes. Most of the research in my lab has focused on the bacterial species Lysobacter enzymogenes as the biocontrol agent, but other bacterial groups, such Bacillus and its relatives, and fungi, e.g., Trichoderma, also have been used. My lab has investigated biological control in greenhouse and field settings against a number of disease systems including Fusarium head blight (Fusarium graminearum) in wheat, white mold (Sclerotinia sclerotiorum) and rust (Uromyces appendiculatus) in dry bean, brown patch (Rhizoctonia solani) in turfgrass, and cyst nematode (Heterodera glycines) in soybean. Understanding how biocontrol agents inhibit pathogens is a major objective in my research. My lab has demonstrated that production of lytic enzymes (chitinases and glucanases) and a secondary metabolite (dihydromaltophilin, aka HSAF), as well as induction of host resistance, play important roles in biological control of fungal pathogens and plant parasitic nematodes  by L. enzymogenes. Current efforts in this research area are directed to elucidating environmental factors and genetic regulatory systems that influence the expression of biological control mechanisms.

Another reflection of my “green” bent is my research project on pathogens and diseases of switchgrass being developed as a biofuel crop. My lab has shown the rust species (Puccinia emaculata and Uromyces graminicola) and the virus combination of Panicum mosaic virus (PMV) and the satellite virus SPMV to be major pathogens of switchgrass in the North Central region. We also identified switchgrass populations having resistance to rust and the viral pathogens. These disease-resistant populations might be deployed as biofuel crops or be the bases for future improvement of biofuel switchgrasses.