Developing durable resistance to root-knot nematode

The latest Potato Progress XVII(3) report has been released by the Northwest Potato Consortium, and features an article titled “New approaches to root-knot nematode resistance,” authored by Cynthia Gleason with the department of plant pathology, Washington State University. This article outlines current research to develop potato varieties resistant to Columbia root-knot nematodes (CRKN), so the potato industry can one day reduce its reliance on fumigants and pesticides to manage nematodes in the field.

As explained in this article, producing cultivars with durable resistance to CRKN is not as simple as successfully introducing natural resistance found in wild potato varieties into new cultivars. Nematode populations can change to overcome plant resistance. To take the efforts a step further, Gleason’s lab is studying what happens in the plant when nematodes become successfully established, a process called the susceptible response. Gleason is finding out what the nematode needs from the plant for a successful susceptible response.

In her report, Gleason describes what the nematode needs to survive from the plant and new efforts to disrupt the nematode’s feeding process in the plant by creating a resistant response. As she explains in the article: “My lab’s long term goal is to develop resistant potatoes that will reduce reliance on soil fumigants and nematicides. To achieve this goal, we want to exploit plant susceptibility genes that encode plant proteins. We want to target genes for modification so that genes that are critical to the success of the pathogen are now absent. To overcome this, the nematode would need to gain new gene activity. This unlikely event means that modified disease susceptibility genes are more likely to provide durable, broad-spectrum resistance.”

Gleason continues by describing how the use of genome editing technology known as CRISPR-Cas9 can be used to mutate “susceptibility genes” in the plants that nematodes would rely on. This would effectively “turn off” their ability to establish feeding sites. This technology can potentially be used to develop plant resistance in many plants in a wide array of crops.