The United States is weighing whether to allow a genetically engineered (GE) version of the American chestnut tree to spread in the wild, which became functionally extinct around the beginning of the 20th century.
Key points
- The exotic fungus Cryphonectria parasitica, nearly drove the tree out of existence.
- Ever since, millions of American chestnut stumps have continued to sprout every year, but only a handful of them survive long enough to produce nuts.
- Most of them get re-infected with the blight and die, restarting the cycle again.
- The US scientists have already developed and field tested the GE version, known as Darling 58, and is now awaiting clearances from government agencies to grow them in the wild.
- Researchers added an enzyme from wheat that breaks down the toxin produced by the blight to develop the Darling 58 line of blight-tolerant trees.
- Half of the nuts produced with the genetically engineered pollen will carry DNA meant to fight the blight.
- The researchers are now ready to sow the seeds in the wild, pushing to become the first in the United States to use genetic engineering to bring a forest tree back to its former glory.
Concerns
- The debate has started over the promises and perils of genetic engineering trees. If they are successful, it will be the first GE forest tree species planted specifically to spread freely through forests.
- Once released, there will be little potential to track or reverse its spread.
- Critics say releasing the transgenic tree is akin to running a massive and irreversible experiment in the wild.
- GE trees pose a particularly high risk of contaminating other trees, along with the animal and insect species that rely on them.
- There are also concerns over the lack of information on how a GE tree will behave as it ages. A chestnut tree survives for over 200 years and throughout its life faces many environmental conditions: drought, flood, heat, pest attacks and others. The impact of GE trees on indigenous communities is another concern put forward by experts.
GE tree varieties in other countries
- While the US is the only country that is considering the introduction of GE tree varieties in the wild, many others have been experimenting with GE tree varieties for commercial plantations.
- In 2002, China allowed the commercial plantations of two varieties of GE insect-resistant poplar trees.
- According to Malaysia-based non-profit World Rainforest Movement, the country has planted about 1.4 million GE poplar trees on 300-500 hectares.
- While China is the only country where commercial plantations of GE trees has started, the US, Germany and Canada are also conducting field tests for GE poplar varieties.
- In 2015, the US and Brazil gave the go-ahead for commercial plantations of GE versions of loblolly pine and eucalyptus trees, but the plantations did not take off for various reasons.
- India has been experimenting with a GE variety of rubber tree for the past two decades. The Rubber Research Institute of India received clearance for field trials in 2010, but had to abort its plans after the Kerala government did not allow the trials. In June 2021, the research institute under the Rubber Board got the nod from the Assam government to carry out the field trials.
- The GE variety has been modified by inserting additional copies of the gene MnSOD (manganese-containing superoxide dismutase) which enables the plant to tolerate extreme climatic stress, says James Jacob, former director of the Rubber Board.
Genetically engineered species
- An organism is considered genetically engineered if it was modified using techniques that permit the direct transfer or removal of genes in that organism.
- Such techniques are also called recombinant DNA or rDNA techniques.
- With genetic engineering, scientists can change the traits of plants and animals by inserting DNA pieces, whole genes, or long stretches of DNA segments from many different organisms. These genetic sequences can also be taken from the same species or be newly made up.
