A new genetically modified mushroom has evaded the US Department of Agriculture (USDA) regulations on genetically modified organisms (GMOs) due to a loophole in their policy. The USDA posted an online letter in the form of a PDF document on 13th April, detailing why the new White Button Mushroom (Agaricus Bisporus) won’t have to face compulsory restriction imposed on other GMO foods fated for consumption. The seemingly harmless button mushroom has once again fired up the debate on the use and safety of GMO foods in the US.

About 90% of the mushrooms consumed in the US are the Agaricus white button mushrooms. In 2015, it was found mushrooms are grown commercially in almost every state with 354 registered growers, and currently the revenue value of the white button mushrooms in America is an estimated $1.23 billion.

Yinong Yang, PhD and an Associate Professor at the Pennsylvania State University, developed the button mushroom using an innovative genetic engineering technology called CRISPR, which stands for ‘Clustered regularly interspaced short palindromic repeats’.

Yang used CRISPR to alter 2 bp i.e., base pairs from the specific polyphenol oxidase gene in the organism. The deleted regions in the gen were only 1-14 bp long. The modification resulted in the formation of the variant called the CRISPR/Cas9-edited white button mushroom, which is 30% more resistant to browning than the natural form. Yang submitted the letter to the USDA last October in 2015 to ask whether or not his newly designed mushroom will be scrutinized as a mushroom.

“Anything for food or feed consumption, usually the company submits the data to FDA for approval,” said Yang as quoted by the National Public Radio (NPR). Yang also noted “this process is voluntary, not mandatory”.

Browning in mushrooms occurs when the pigment ‘Melanin’ forms in the mushrooms as a result of oxidization reactions. The new anti-browning traits in the mushroom variant will lead to a greater shelf life and enhanced appearance of the mushrooms packaged as edible products. CRISPR allows greater precision in splicing — cutting/modifying — genes than ever.

In the letter the Animal and Plant Health Inspection Service (APHIS) Division of the USDA passed the verdict, stating the mushroom will not be subjected to the GMO regulatory system because it does not contain any foreign particles i.e., DNA. The mushroom had only been genetically altered by the deletion of its own genes. Usually the foreign particles used in GMOs are of either bacterial or viral origin and added to certain crops so they have greater resistance to pests.

“APHIS does not consider CRISPR/Cas9-edited white button mushrooms as described in your October 30, 2015, letter to be regulated pursuant to 7 CFR part 340,” stated the USDA in reply to the letter.

The mushroom is the first food product produced by using CRISPR which has sidestepped USDA regulations for GMOs. Previously 30 new crop variants had used the same excuse to get out of the USDA regulation examination, in the last five years.

In the same way, numerous other biotechnology companies and scientists are using CRISPR to design new food variants. The technology company DuPont is working on developing wheat and corn alternatives, which are drought-resistant using CRISPR, while Korean scientists are developing a fungus resistant banana with the help of CRISPR.

Even though the new mushroom strain has by-passed protocols, it will not be readily sold in the grocery store isle anytime soon. The mushrooms will still have to be passed by other rules such as the APHIS’s Plant Protection and Quarantine (PPQ) permit, to ensure food safety. Following the online uproar by the American public, the US National Academy of Sciences held a meeting to reanalyze their policies in light of new and emerging technologies on 18th April.