Go-Ahead Of Gene-Edited Mushrooms In the US Signals New Phase In The GMO Debate

Elpidio V. Peria
17 April 2016

whitebutton mushrooms

The US Department of Agriculture recently gave a US researcher the go-ahead to commercialize a gene-edited mushroom, in effect letting these types of agricultural produce bypass current US rules on GMO regulation.

This will have an impact in how the Philippines will regulate GMOs given that there is a strong policy push on the part of Philippine government agencies, especially the Department of Agriculture and the Department of Science and Technology, in promoting biotechnology in agriculture, and with greater inter-agency scrutiny on food safety and environmental impacts that is now in place brought about by the recent revision of government rules on GMOs for food, feed and processing including those used in agriculture, which came about due to the Philippine Supreme Court ruling last December 2015, this seemingly innocuous US development will also spur intense debate on GMO regulation not only in the US but also in the Philippines.

As reported in Nature, Yinong Yang, a plant pathologist at Pennsylvania State University, engineered the common white button (Agaricus bisporus) mushroom to resist browning. The effect is achieved by targeting the family of genes that encodes polyphenol oxidase (PPO) — an enzyme that causes browning. By deleting just a handful of base pairs in the mushroom’s genome, Yang knocked out one of six PPO genes — reducing the enzyme’s activity by 30%.

The same report also noted that fruits and vegetables that resist browning are valuable because they keep their color longer when sliced, which lengthens shelf life. In the past 18 months, biotech companies have commercialized genetically engineered non-browning apples and potatoes

White button mushrooms are commonly eaten and used in various dishes; it is usually known by its French moniker, champignon, and it also has a lot of medicinal properties, to protect against breast cancer, liver cirrhosis, etc.

Advocates who worry about GMOs will look at this development with dismay, given that the regulation of these types of agricultural products, from an emerging field called synthetic biology, are still not clear, be it at the international level, where it is currently being discussed by the Convention on Biological Diversity, or here in the Philippines.

These products are the result of a technology called CRISPR-CAS9, where certain genomes of bacteria are used to cut and paste certain parts of a gene, thus enabling that corrected part of the DNA become a normal part of the gene, though with changed characteristics.

From this technology has come hornless cows, midget pigs, colorful zebra fishes, and any other seemingly chimera-type of species.

CRISPR is shorthand for Clustered Regularly InterSpaced Palindromic Repeats, which  are repetitive fragments of DNA scattered inside a bacterial genome. It is these fragments that are targeted by the CAS 9 protein thus enabling that fragment to be snipped and replaced with a similar strand.

By analogy, we can think of the CRISPR technology like what Pinoys usually term as “snowpake”, or liquid eraser which is put in a misspelled word in a sentence in a printed document and that misspelled word is corrected, thus the sentence reads better than if they are left alone.

Both sides of the GMO debate will have a field day discussing the merits and demerits of this technology, but the fact remains that these products will still have to get regulatory approval via the US Food and Drugs Administration if they are to be eaten and with the US Environmental Protection Agency if they are to be eventually propagated in the open fields, which is what will also happen here in the Philippines if Pinoy scientists are already moving also in this field.


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