Demystifying The Soybean Aphid, One Gene At A Time
It’s easy to miss the soybean aphid unless you’re really looking — just a single, pepper-sized fleck on the underside of a soybean leaf. But don’t be fooled by the small size.
This invasive insect has been doing large-scale damage across Midwestern farms for almost 20 years now. Farmers and researchers are still trying to understand how best to manage it.
In a quest for answers, entomologist and OSU Associate Professor Andy Michel is “looking under the hood,” so to speak, into the insect’s DNA.
Michel and his colleagues were the first to publish the full 20,000 gene sequence of the soybean aphid last year. It is only the fourth aphid genome sequenced to date and arguably the most important one for Ohio soybean growers.
“Having the genome available makes it easier for us to understand what these genes are and how they’re able to overcome resistance,” said Michel.
He likens the process to creating a reference library. What researchers need to do now is search the “library” for any books – in this case, genes – that might be involved in the aphids’ resistance to insecticides or naturally resistant plants. It won’t be easy, but it’s a huge first step.
“It’s still a lot of work to find that book,” explained Michel. “Just like we have to do library catalogue searches, scientists have to search the genome for a gene of interest. But without that library, finding it would be impossible.”
Once scientists identify a resistance-related gene, they can use it as a molecular diagnostic tool. For example, the OSU team might go out to a grower’s field to sample the aphids and examine their genetic makeup.
“We could determine how likely it is that the population of soybean aphids is resistant to a chemical even before that grower sprays,” said Michel. “It would prevent wasted or ineffective sprays.”
The genome can also help scientists combat the insect adaptation directly by developing a way to shut down the related gene with something like a genetically modified soybean variety.
At the OSU Soybean Center, Michel is able to collaborate with many different kinds of scientists: plant breeders, geneticists, plant pathologists and more. This goes a long way towards helping him understand the complex interactions in various crop systems. Insect pests like the soybean aphid run in tandem with other important crop traits and diseases.
“Soybeans do not grow in a vacuum. I try to work with as many scientists as I can to look at soybean management as a system,” Michel said. Michel is grateful for the funding and support local growers provide to his work. The soybean aphid genome project, in fact, would not have been possible without the Ohio Soybean Council’s funding. Read more about Michel’s work.