Seedling pathogen research is just the beginning
“Using bioinformatics, the computer can match the identified sequence from the sample with an organism in the database,” explained Bond. “While not everything is in the database, we can find out a lot of what is going on in the soil that has been sampled.”
Although some of the tools being used, like genetic sequencing, have been available, they were limited and expensive. “If you would have said three or four years ago that you wanted to sequence everything found around these plants, you would have been laughed out of the room,” said Bond.
The tools themselves have expanded the horizons and accuracy of the evaluative process. Classical techniques like microscopic analysis required growing an isolate in a pure culture. That limited the technique to those organisms that can be cultured in the laboratory. Molecular probing is not limited that way.
Once sampled, examined and identified, the next step is to develop marker probes that will aid in rapid diagnostics in the lab, if not yet in the field itself. These probes could speed up and expand the results from a process that currently can take weeks.
“When you get a disease in the field, you don’t want to wait around,” noted Bond.
DEVELOPING NEW DISEASE MANAGEMENT TACTICS
Knowing what is actually in the seedling complex of pathogens and other organisms found with them opens the door to refine appropriate disease management scenarios.
This involves identifying baseline sensitivity of the organism to seed treatments, a process that will identify those most effective to given pathogens and more.
“As we collect cultures and isolates, we can compare them to the isolates that have not been exposed to seed treatments. These samples exist in collections like those at Iowa State, the University of Illinois and the University of Minnesota,” said Bond. “Over time, we can evaluate if given Rhizoctonia or Fusarium isolates are becoming less sensitive or developing resistance to certain seed treatments.”
Another aspect being addressed is the impact of crop rotations on Pythium and Fusarium. “We do know that the simple fact of planting a crop can affect the biological life in the soil,” noted Bond. “While we don’t have a focus on cover crops as part of the study, we know they can have an impact from other research done.”
As an example, Bond cited a field trial with rapeseed and canola at Southern Illinois University. When those crops were turned under in the spring, less sudden death syndrome (SDS) was recorded in the soybean crop. “The SDS pathogen isn’t the most aggressive at causing seedling death in our area, not like Pythium or Rhizoctonia,” he said. “However, we were amazed at the impact these cover crops had.”