by Dr. Emil Javier
April 9, 2016
There are those who look at things the way they are, and ask why… I dream
of things that never were, and ask why not?’
– Robert Kennedy
Since we do not grow apples and not much potatoes and both are minor items in our diets, what are our interests in non-browning genetically modified (GMO) apples and potatoes?
Not much really, directly, except for the implications of their commercial release with the debate on the relevance of genetically modified crops to our economy. Recall that last year the Supreme Court (SC) banned further field trials of GMO Bacillus thuringiensis (Bt) eggplant and required government to craft clearer regulations to guarantee the Filipinos’ right to healthful and balance ecology under the Writ of Kalikasan.
The five departments (Agriculture, Environment and Natural Resources, Health, Science and Technology, and Interior and Local Governments) have complied with the SC directive and have issued a new Joint Department Circular to replace the maligned DA Administrative Order No. 8. And so far now, at least for the time being, the executive branch is proceeding with its stated policy of safe and responsible of modern biotechnology.
The approval for commercial propagation by responsible authorities in Canada and United States of apples and potatoes that have been purposely bred through genetic engineering techniques not to be discolored after the fruit is sliced and exposed to the air is noteworthy for three reasons: The world of agricultural biotechnology is moving on, whether we are part of it or not, and the objectives of improvement are necessarily those of economic interest to the countries developing them.
Conversely, if we want to see technological progress on the crops and traits of interest to our farmers and consumers, we can rely on the efforts of advanced countries, only to the extent that their economic interests coincide with ours. Otherwise we are on our own!
The second noteworthy consideration is the less threatening kind of genetic technology applied to produce the desired outcome. The first generation GMOs are transgenics, i.e. alien genes were transferred from unrelated species like the Bt gene for insect resistance from bacteria. This “unnatural” transfer of genes has raised concern on unanticipated consequences.
However, these new non-browning apples and potatoes are cisgenic — no alien genes were transferred but the expression of some native genes have been modified through a technique called gene silencing.
The third difference is while the first generation GMOs were helpful to the farmers to grow and protect their crops, this time the benefits accrue to consumers with better quality and more healthful products.
Gene Silencing – A Less Threatening Kind of Genetic Engineering
Many fruits including apples, pears, avocadoes, melons and bananas turn brown after they are sliced open and exposed to the air. The fruits are not rendered inedible nor spoiled but they do not look presentable especially when they are prepared into fresh fruit salads.
The usual kitchen remedy is to squeeze lime juice which has anti-oxidant properties on the newly sliced fruit to prevent browning.
However, as far as the biotech developers were concerned, the immediate target of the technology is not the kitchen but the rapidly expanding and very profitable fruit fresh cut business in groceries and supermarkets in the developed countries. On the other hand, for potatoes the target are the food processors of French fries and potato chips who want to keep their potatoes spotlessly golden yellow, not brown.
The phenomenon of browning is based on the action of the enzyme polyphenol oxidase on phenols, the family of organic aromatic compounds technically described as having at least one hydroxyl group attached to the benzene ring. The phenols are oxidized into reactive chemicals called quinones which together polymerize to form the unsightly brown pigments.
Both the enzyme and the phenols naturally occur in fruits but they are physically separated in the cell. The polyphenol oxidase enzyme is confined in cell organelles called plastids while the phenols are in the vacuole. When the fruit is sliced, the integrity of the plastids is broken and the enzyme gets in contract with the phenols which result into the brown reaction which is visible in a few minutes.
By a new technique called RNA interference, the native genes responsible for producing the polyphenols oxidase enzyme are silenced and thus unable to produce the enzyme. This technology had been incorporated into the “Arctic” varieties of apple by Okayama Fruits a small company in Canada and in “Innate” varieties of potato by Simplot, a huge potato producer in the United States.
Additional Desirable Traits in “Innate” Potatoes
However the second generation Innate potatoes developed by Simplot added three more GMO traits apart from the non- browning property. They have built in resistance to potato late blight, the destructive pathogen which caused the Irish potato farming in 1846 and which till today is the most devastating disease of potato. They accomplished this by transferring a resistance gene into cultivated potato from Solanum venturii, a wild potato species in the Andes Mountains of South America.
The new Innate potato likewise offers a unique consumer benefit by reducing the presence of acrylamide, a suspected human carcirogen, which is found in potatoes cooked at high temperature like potato chips and French fries.
Acrylamide is the product of the reaction of asparagine, a non-essential amino acid, with reducing sugars. By silencing the genes that produce asparagine they reduced the potential of the new potato to produce acrylamide.
The third beneficial trait of the second generation Innate potato is lower reducing sugars in the tubers which enable the tubers to be safety stored in cold storage at 38oF for more than six months without impairing quality.
The world of agricultural biotechnology is moving on whether we are a part of it or not. The non-browning apples and potatoes described above are indicators of what the new products look like. In both cases, they are of marginal interest to us for the obvious reason that we are not the intended market. It goes without saying that we can rely on global innovations only to the extent that the economic interests of the technology developers coincide with ours.
And so for the crops and traits of specific interest to Filipino farmers and consumers we are very much on our own!
It is therefore foolhardy and against our self-interest to deprive ourselves of the means to advance our national interest. We should persevere in mastering biotechnology ourselves and in investing in our people and research institutions. The controversial Bt eggplant developed by our plant breeders in UP Los Baños is evidence we can hold our own.
Dr. Emil Q. Javier is a Member of the National Academy of Science and Technology (NAST) and also Chair of the Coalition for Agriculture Modernization in the Philippines (CAMP) For any feedback , email email@example.com