Problem: Corn crop death happening by the European corn borer and other lepidopteran maize pests. GMO that addresses this problem: Bt (Bacillus thuringiensis) maize. The European corn borer and other lepidopteran maize pest feed on corn kernels and tissues of the corn plant, which can destroy the entire maize. To address this problem scientist used Bt protein. Bt protein was sprayed on the fields to block the pest for past decades. However, when the Bt protein couldn’t survive from high UV (ultraviolet) light and it had to be re applicated after getting washed off by the heavy rain. (Federation of American Scientists, 2011) To address this problem scientist added genetic material of Bt that produces the crystal toxin protein to the maize through molecular techniques. By doing this, scientist makes the plant itself poisonous to their pests. (F.B.Peairs, 2019)
How science is applied to address the problem:
- First, Scientist extracts DNA out of its soil bacterium. At this process all the DNA in the soil bacterium is extracted at once, which means that both Bt gene and different genes of the soil bacterium is extracted. To isolate the gene that is desirable for the plant, scientist use restriction enzyme and DNA ligase. Restriction enzyme recognizes the specific sequence of the DNA and it cuts the specific sequence. After the restriction enzyme does its job, DNA ligase joins the parts of DNA fragment together.
- Second, Scientist proliferate the amount of Bt protein by gene cloning, a process that makes thousands of exact copies of the DNA sequence.
- Third, Scientist will design the gene to work inside a various type of organism. They cut the gene and replace certain region with enzymes.
- Forth, it is impossible to insert the transgene every cell of the plant cell because it has millions. The DNA sequence is mostly inserted in its embryo stage so that when it matures the Bt gene is expressed in all cells and it is insecticidal.
So, tissue culture is used to proliferate masses of cells that have not developed in specialized tissue called callus. This new gene is inserted into the plant with different techniques. Common one that is known is Agrobacterium, microfibers and electroporation. Main purpose of this methods is to deliver the new gene to nucleus without getting killed. From here, the new DNA might be successfully inserted to chromosomes. The plants which are totipotent may develop this single cell to the whole plant – Lastly, the transgenic plant is grown in greenhouses and the produced seed, which inherits the transgene, is collected. These seeds are over to a plant breeder for backcross breeding. These transgenic plants are cross breed with elite lines to make high yielding transgenic lines. (Javier Romero, 2008) (National Research Initiative Competitive Grants, 2019 )
When this Bt maize is ingested to the susceptible insect. Within minutes, the Bt protein binds with the specific receptors in the gut wall. The interaction of these protein and receptor weakens the gut wall and eventually form holes. Their digestive system is opened and works not properly, and pest dies from the starvation. (Science, 2017) The limitation and benefits from Bt-maize The economic benefit created from Bt maize is caused by the population suppress of European corn borer, decreased amount of insecticide use, and higher yields. The decrease of corn borer benefits both Bt and non-Bt maize growers because European corn borer is a pest that harms both maize and other plants. Recent research provides an estimation that in 14 years there would be an additional 3.2 billion profit for the maize growers and 2.4 billion for non-Bt maize growers at U.S. (W.D.Hutchison, 2010) Bt corn has innate pest resistance in the plants, so the farmer doesn’t have to spray chemical insecticide as much as the past.
This leads to both health benefit of the farmer and environmental benefit on the farm. Estimated by Brook and Barfoot, the chemical insecticide used on the Bt maize has decreased 35% (29.9 million kg) globally from 1996~2008. (Brookes G, 2010) The controlling the corn borer with insecticide was not effective after larvae have tunneled into the stalk. When entomologist began the experiment with Bt maize at early 1990s, the plant was nearly bulletproof to corn borer injury. European Corn borer was responsible for yearly yields reduction by 5.5%. (The Pennsylvania State University, 2019 ). Since 2002, At South Africa introduction of Bt corn had yield increase by 24.6%. The environmental benefit happening by Bt maize is the protection of honey bee. The disadvantage is occurring by Bt maize’s genetic drift. Bt corn is a plant that is genetically modified for insect resistance. This raises awareness that Bt corns can influence crucial pollinator earth, Honey Bees (Apis mellifera L.).
In the 25 studies that assessed potential implication of Bt corn suggests that Bt corn only affects European Corn Borer and Lepidopteran pests, and do not affect the survival of Honey Bee. This is because Cry protein that is found in Bt is selective and only affects lepidopteran pests. (Jian J. Duan, 2008 ) This is important because the honey bee pollinates over 75% of plants and crops, which produces food for human. (Garnier, 2017) If the Honey Bee is affected by the Bt-corn and the population decreases, the stability of our food chain will diminish. When Bt corn is planted somewhere close to non-GMO farm is highly possible that the corn at the non-GMO farm will be contaminated and become a Bt corn. Corn cross-pollinate by pollen being dispersed in space by wind and gravity (Ohio State University Extension, 2016). Without noticing, a farmer who was growing non-GMO corn would change to GMO crop. (Farm management, 2017 ) The social disadvantage of the bt maize is that we are not sure if Bt-corn is entirely safe or not. Supporters of GMO corn claim that the Bt toxin gets destroyed in the digestive system and it is to humans.
However, a study published in ‘Life Sciences’ at 1999 discovered that when Bt was injected to mice, it caused a significant immune response. Also, when scientists insert genetic material into the DNA of an organism, it is done at random. Each random insertion creates the possibility for a new toxin to be formed, turning a safe food into something hazardous. Unfortunately, there are no long-term studies to either prove or disprove the safety of GMOs. (Hellmich, 2012) Conclusion: Bt Maize, a GMO plant, needs careful examination before use. It is supported by science that the cry protein that is in the Bt gene helps reduce damage done by its pest. For economic purposes, Bt maize is undoubtedly a profitable plant because it minimizes the use of insecticide, yields more products, and the pests do less harm to your plant.
Except when you are in a country that any GMO is restricted. For example, US doesn’t restrict the sale of the GMO product, but Japan has zero tolerance for any food that is unapproved GMO material. (Ohio state university extension, 2016) Many scientists state that GMO is safe, but no long term proves or disproves the safety. So this is another part you will need to consider before using it. Also, the use of GMO is not an individual problem it is a problem that is shared by the whole community. If one farm starts to raise a Bt-corn, it can influence the farm beside you and think of the future. No evidence approves the Bt-corn farmers should have deep consideration of advantages and disadvantages of raising a bt corn.
