Hidden host associations for the soil-borne fungal pathogen, Verticillium dahliae

Glenna Malcolm, Penn State

October 24, 2011 @ 04:00 pm to 05:00 pm

105 Forest Resources Building

Event Website

Verticillium dahliae is a soil-borne pathogen that causes Verticillium wilt in hundreds of dicotyledonous crop plants. Control of Verticillium wilt is difficult because after colonizing the roots of plants, invading the vascular tissue, and causing subsequent death, the pathogen forms microsclerotia in the dying plant tissue. Microsclerotia act as the fungal inoculum that can persist in the soil for up to ten years. Farmers have attempted, with varying rates of success, to mitigate wilt symptoms by rotating cereal crops with host crops to reduce fungal inoculum in fields. Cereal crops, along with other monocotyledons, have been considered as non-hosts, but evidence suggests that they may be asymptomatic hosts._ The fact that V. dahliae likely colonizes these and other asymptomatic hosts suggests that the host range for the pathogen may be much larger than originally thought._ The potential also exists for this fungal species to have multiple functional roles: pathogen and endophyte._ Further, by focusing only on fungal pathogen-plant interactions with V. dahliae, we ignore aspects of the ecology, spread, and persistence of this pathogen in ecosystems._ For example, I compared the genetic diversity of V. dahliae populations colonizing an asymptomatic host plant and symptomatic host plants of varying susceptibility to the disease to determine if different portions of the fungal population might be interacting with different host plants._ I will discuss these results and others, plus implications for farmers with Verticillium wilt problems and for the wider scientific community.

Contact

Jason Hill
ecologyservice@psu.edu