Restrictions on GM potatoes have been lifted in the US

A new genetically engineered potato developed by Michigan State University potato breeder Dave Douches has been granted exemption from the biotechnology regulations placed on genetically modified products by the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA APHIS).

The Kal91.3 potato is bred from an MSU potato variety named Kalkaska. The newly developed potato can be stored in cool temperatures for long periods of time without sucrose, the compound that sugar is typically stored in potatoes as, converting into reducing sugars such as fructose and glucose. Without as many reducing sugars, off-color browning and caramelization can be minimized in the Kal91.3 potato, leading to healthier and higher-quality products, including potato chips. The Kal91.3 potato can also reduce the environmental impact of the growing process without as many fertilizers and pesticides needed to maintain the potato during storage.

Sucrose is broken down in potatoes by vacuolar acid invertase, an enzyme reactive to the external environment of plants — such as temperature. Roughly 10 years ago, Jiming Jiang, an MSU Foundation Professor in the departments of Horticulture and Plant Biology, published findings on how to silence, or suppress, the gene that produces vacuolar acid invertase in potatoes.

“Breeding potatoes is quite challenging because we need so many important traits to line up, but in this case, we just needed one trait to correct the problem. Using this biotech strategy, we succeeded in making a potato that was giving us problems into one that’s now commercially valuable.”

After multiple experiments Douches developed an RNA interference (RNAi) construct that silenced vacuolar acid invertase in Kalkaska potatoes. From 2016-2023, Douches tested the agronomic characteristics of the Kal91.3 potato and found it had a good shape, size and specific gravity — the measurement of starch content compared to water in the potato.

In January, Douches received notice from USDA APHIS that the Kal91.3 potato proved not to pose an increased plant pest risk relative to its conventionally bred counterpart, thus making it exempt from the biotech regulations USDA APHIS imposes on other genetically modified products.

The Kal91.3 potato isn’t the first genetically engineered potato with invertase silencing to be exempt from regulation by USDA APHIS. However, it’s the first genetically engineered vegetable developed by a land-grant university to be exempt from regulation, according to the USDA APHIS website.

Douches and his team are now working with Michigan potato industry leaders to evaluate the potential impact the Kal91.3 potato might have on the state’s industry, specifically with chipping. Michigan is the eighth-largest producer of potatoes in the U.S., with 70% used for chips.

Kelly Turner, executive director of the Michigan Potato Industry Commission, said the storage capacity of the Kal91.3 potato has a chance to further stabilize Michigan’s potato industry with a steady supply of potatoes throughout the year, even when fresh harvests aren’t available.

Tags: USA, potato