A species of genetically engineered mushroom has been freed of regulation by the U.S. Department of Agriculture (USDA). This means that it can be cultivated and sold without being overseen by the USDA, according to a news report published online in Nature recently. Though about 30 genetically modified organisms have been similarly freed by the USDA, the special thing about this mushroom species is that this is the first organism to have been edited using the tool CRISPR-Cas9, which has been making waves in the field of genome editing, lately.
Known as the common white button mushroom, this fungus species ( Agaricus bisporus ) was genetically engineered by Yinong Yang of Pennsylvania State University using CRISPR-Cas9. The engineered mushrooms do not brown easily when sliced. This can improve their shelf-life, thereby rendering them valuable commercially.
The browning of the mushroom is caused by the enzyme polyphenol oxidase (PPO) and the above effect may be got by removing the genes that code for this enzyme. By removing some base pairs from the mushroom’s genome, Dr Yang succeeded in getting rid of one of the six PPO genes which reduced the enzyme’s activity by 30 per cent.
This process did not introduce foreign DNA from other viruses and bacteria. This is perhaps the reason why the modified mushroom was given the green signal. Among the 30 plant species that have escaped the regulatory framework is a rose-coloured pineapple variety.
Cultivating genetically modified crops is a huge industry which may be undergoing a massive rethink involving a three-pronged argument, with the industry on side, the biologists on another and activists opposing it from the third. The U.S. National Academy of Sciences, Engineering and Medicine will meet on April 18 to discuss this issue and, among other things, bring out a report that will predict what kind of advances will be made in biotechnology products over the coming years. The report will also comment on regulatory processes.
There is a whole spectrum of rules and regulations in countries around the world when it comes to research in genetic engineering and implementation of the results of research outside the lab. A case in point is that of germline editing using CRISPR, in which area many countries have even banned research. With regard to genetically modified crops, the U.S. has been quite liberal and it is likely to become more so.
The organisms that have currently been given the green signal involve somewhat simple steps of editing such as knocking off a set of genes to create a desired effect. As the technology advances, more complex procedures will be initiated and so the whole process of regulating these products will need to be reviewed as and when that happens.