By Erin Hodgson Associate Professor
Many of you know about naturally-occurring entomopathogens in the soil that can kill or suppress insects. Bacillus thuringiensis (Bt) is a well-known example of a bacteria that kills insects, and was eventually included in plants as a transgenic protein. My Ph.D. student, Eric Clifton, spent his whole master's degree finding entomopathogenic fungi (EPF) in Iowa. Not surprisingly, he found lots of different EPFs in corn and soybean fields. You can read about his thesis results here.
Today, I followed Eric around the lab while he is starting a new research project. He is interested in learning about how EPFs can help induce plant defenses. This is a relatively hot topic, as you can imagine giving plants a "vaccine" of sorts to help fight off pests like insects and nematodes sounds too good to be true. A good, but technical, paper that reviews induced plant defenses can be found here. Eric is looking at two common EPFs for this study, Metarhizium anisopliae and Beauveria bassiana.
Eric's plant inoculation is a multi-step process, but basically he creates a fungal slurry and coats soybean seeds. It kind of reminds me of a seed treatment. He is measuring how many soybean aphids are produced on EPF-coated seeds versus untreated seeds. So far, the results are showing some induced plant defenses from this EPF seed treatment. We have so much to learn, but thought you might find this idea interesting.
Dry spores of Metarhizium anisopliae (top) and Beauveria bassiana (bottom).
Sterilized soybean seeds (top) are soaked in a fungal slurry (bottom) for 24 hours before planting.