Plants producing DHA

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February 2013

Plants producing DHA

CSIRO researchers published results in November 2012 showing that the long-chain n-3 fatty acid docosahexaenoic acid (DHA) can be produced in land plants in commercially valuable quantities (PLoS ONE 7(11):e49165. doi:10.1371/journal.pone.0049165).

James Petrie and Surinder Singh, along with six other CSIRO associates, genetically engineered Arabidopsis thaliana, a well-studied plant that is related to rapeseed (Brassica napus), to produce DHA at levels of 15%. This is the first time a level of 12% has been exceeded, the level at which DHA is generally found in commodity bulk fish oil.

The authors suggest that the technology should be applicable in oilseed crops. They point out, “One hectare of a Brassica napus crop containing 12% DHA in seed oil would produce as much DHA as approximately 10,000 fish.” (This calculation is based on 10,000 kg fish = 1,000 kg oil = 120 kg DHA. The following assumptions were incorporated: Average fish = 1 kg; fish oil yield = 10% by mass; average DHA content = 12%. Calculations would change for smaller fish and for less oily fish. Assumptions in developing the comparison were that 1 hectare yields 2.5 metric tons of B. napus, which corresponds to 1,000 kg oil or 120 kg DHA, if the seed contains 40% oil by weight.)

Furthermore, the authors reported the plant produced oil with a high n-3/n-6 ratio (>10), a ratio that is similar to what occurs in many marine oils.

The key to the CSIRO discovery was the use of a transgenic pathway to increase the content of C18 α-linolenic acid, which was then converted to DHA via a microalgal Δ6-desaturase pathway.

What happens when GE patents expire?

The US agricultural industry will be discovering the answer to that question over the next few years. In 2014, the patent on the first genetically engineered (GE) trait, Roundup Ready soybeans, will expire, and the first cotton trait will expire in 2016. The industry is exploring the idea of what a potential generic trait market will look like. Another important issue will be how, or whether, international regulatory approvals presently in place will be maintained. If they are not, trade could be disrupted.

In light of these questions, the Biotechnology Industry Organization (BIO) and the American Seed Trade Association (ASTA) announced a framework, referred to as The Accord, to develop answers. Their Generic Event Marketability and Access Agreement (GEMAA) took effect on November 15, 2012. Signatories to the agreement include BASF Plant Science, Bayer Crop Science, Dow Agro Sciences, DuPont Pioneer, and Monsanto Company. The agreement addresses the transition of commercial biotechnology events as they go off patent.

According to Andrew LaVigne, president and chief executive officer of ASTA, “The expiration of patents for biotechnology events not only creates opportunities for growers and the seed industry but also creates challenges that must be addressed.” He added, “The most pressing challenge presented by patent expirations of biotechnology events is the maintenance of global regulatory authorizations for these events as well as associated stewardship obligations so that farmers can continue to cultivate their crops grown from seed varieties containing off-patent events without jeopardizing US export markets” (

According to a statement from BIO, signatories to GEMAA that have developed proprietary regulatory information to support the authorizations for events globally would be required to provide notice of patent expiration three years before the last patent on the biotechnology event expires and provide access to the generic event at patent expiration. Furthermore, the owner of the regulatory data must decide whether to main regulatory responsibility on its own for the whole marketplace for at least four years after the last sale of the product, or to share or make arrangements to transfer this responsibility to others. If none of the other signatories express interest, the owner could discontinue the event.

For more information see