Pests are "indigestible," but safe for humans? Gene editing paves the way for next-generation agriculture

A Feast for Pests, a Staple for Humans—The New Phase of the "Starch War"

Corn, wheat, beans, coffee cultivated worldwide.
For these grains, starch is an energy savings bank. Meanwhile, for pests like weevils, rice weevils, and boll weevils (not the cotton aphid but the boll weevil that eats cotton buds), which love starch, it becomes an "all-you-can-eat buffet."Phys.org

A new study featured on Phys.org is attempting to bring the weapon of gene editing into this "starch war." An international team, including the Brazilian Agricultural Research Corporation (EMBRAPA) and the Climate Change Genomics Research Center (GCCRC), published a paper in the Biotechnology Journal discussing a concept to enhance plants' inherent "starch protection defense system" through gene editing to create seeds that are "unpalatable and indigestible" to pests.Phys.org

What is the Invisible Shield "α-Amylase Inhibitor"?

To digest starch, pests need an enzyme called "α (alpha) amylase." This enzyme acts like "scissors" that cut starch chains into sugars.

Seeds of wild legumes and other plants contain "α-amylase inhibitor proteins" that interfere with these scissors. With these inhibitors, pests cannot sufficiently absorb nutrients even if they eat the seeds, hindering their growth and reproduction. In other words,plants coat their seeds with a "non-toxic but hard-to-digest layer."Phys.org

However, over the years, we have bred beans and grains to be "easier to digest and tastier for humans." The research team points out that in this process, many of these inhibitor proteins may have been reduced.Phys.org

Steady Exploration Since the 2000s

The review paper organizes research accumulated in this field over the past 20 years. Specifically,

• exploring genes that produce α-amylase inhibitor proteins from various plants

• evaluating how effective these inhibitors are for each pest and animal species

• developing transgenic (GMO) plants genetically modified to produce more inhibitors

• and obtaining related patents

are the steps involved.Phys.org

The primary targets have been bruchids and rice weevils that ravage long-stored grains. They develop inside pods and continue to reproduce within the stored grains, often leaving farmers worldwide with bags full of powder when discovered.Phys.org

Why "Classical GMOs" Aren't Enough

Then why not create more GMOs by introducing inhibitor protein genes from outside? There is a significant barrier to this.

Traditional transgenic cropsincorporate genes from other species into the crop's genome. Even if scientifically consistent, there remains a strong resistance to "foods containing genes from other species." Additionally, GMOs require rigorous reviews in many countries, inflating development costs and time.Phys.org

Brazil's CTNBio (National Technical Biosafety Commission), which oversees biosafety policy, sometimes does not treat "those modified only with the crop's own genes without introducing genes from other species" as GMOs, depending on conditions.Phys.org

This is crucial for companies.If the same pest resistance can be achieved, gene-edited crops treated as "non-GMO" with lighter regulatory burdens are more attractive for investment.

Boosting "Existing Defense Mechanisms" with CRISPR

This is where CRISPR, a gene-editing technology, comes in. It involves inserting "molecular scissors" at targeted locations on DNA to alter base sequences, without necessarily introducing genes from other species.

The research team's scenario is simple.

1. Identify the genes or regulatory regions that produce α-amylase inhibitor proteins from the crop's genome

2. Use CRISPR to enhance the gene's "switch" or slightly alter the amino acid sequence to increase protein activity

3. As a result, a "targeted inhibitor" that strongly affects pest digestive enzymes but not human or livestock amylase is produced in abundance in the crop's seeds or leaves

The resulting crops become "food that doesn't fatten" for pests, significantly reducing damage while remaining safe and digestible for humans and livestock.Phys.org

The Targeted Pests

The review specifically mentions the following pests as examples.Phys.org

• Bruchids and Rice Weevils: Storage pests that eat beans inside pods and hollow out stored beans from the inside.

• Cotton Boll Weevil (Anthonomus grandis): Lays eggs inside cotton buds, significantly reducing fiber quality and yield.

• Coffee Berry Borer (Hypothenemus hampei): Larvae eat seeds inside coffee cherries, a pest troubling coffee-producing regions worldwide.

These insects target seeds, buds, and fruits rich in starch and sugars. Increasing inhibitor proteins effective against their α-amylase could sustainably reduce damage without relying on pesticides.

How Will a "GMO-Averse" World Perceive It?

How will this concept be received by the public?
As soon as the news was introduced on social media, various reactions emerged (the following illustrates the trends in the discussion).

1. Positive Voices from Environmental and Sustainability Advocates

On X (formerly Twitter), accounts interested in environmental issues and sustainable agriculture prominently post in this tone.

"If pests can be controlled without relying on pesticides, it's welcome. I also appreciate the careful design to avoid affecting human amylase."
"Amid predictions of increased pest damage due to climate change, enhancing crops' 'self-defense' seems reasonable."

Pesticide spraying is not only a cost issue but also affects surrounding ecosystems and the health of agricultural workers. Therefore,the realistic eco-view that "gene editing is an option if it can reduce pesticides"gains certain support.

2. Cautious Opinions from Those Sensitive to Food Safety

Meanwhile, communities sensitive to food safety and health information repeatedly express concerns like the following.

"Does α-amylase inhibitor really not affect human digestion? What about long-term consumption data?"
"Isn't it too favorable for companies to relax regulations by treating it as non-GMO? What about labeling?"

For those who have experienced past GMO controversies, the logic of "it's okay because it doesn't contain genes from other species" and "therefore, it's not GMO" itself feels uncomfortable.It seems necessary to separate "labeling issues" from "substantial safety issues" in discussions.

3. Opinions Viewing It as "Ultimately for Corporate Profit?"

Particularly from some users in Europe and Japan, there is a hint of distrust towards global companies.

"Isn't it more about companies holding patents wanting to monopolize the seed business than pest control?"
"Instead of enclosing with patents, it should be open as a technology freely usable by small farmers in Africa and South America."

Indeed, the paper mentions that many patents related to α-amylase inhibitors have been filed.Phys.org
The issue of "ownership of technology," regarding who holds the rights and who can access itis an unavoidable theme in this research.

4. Realistic Perspectives from Farmers and Agricultural Stakeholders

Comments weighing costs and risks appear from accounts believed to be farmers or agricultural researchers.

"If the risk of stored beans going bad can be reduced, it's quite attractive for farmers. But the key is how much seed prices will rise."
"Regulations in each country and the acceptance of export partners are also important. When using gene-edited varieties for export coffee or cotton, how buyers will judge is crucial."

In other words,even if technically possible, whether it can be "used" from a trade or brand strategy perspective is a separate issue, revealing realistic concerns.

How Much Can We Trust "No Impact on Humans"?

α-Amylase is an essential enzyme for human and livestock digestion.
Researchers aim for selectivity where inhibitor proteins "bind to pest enzymes but hardly to human or livestock enzymes" by designing protein structures.Phys.org

However, the world of protein structure and function can sometimes be unpredictable.
It is necessary to carefully verify possibilities such as being effective against a pest species but also affecting other beneficial insects, or having unexpected impacts on gut microbiota.

On social media,

"Has the impact on pollinators like bees been investigated?"

Such questions are prominent. At present, the paper mainly focuses on the mechanisms and possibilities,and it is reasonable to see that actual field trials are about to begin in earnest.Phys.org

Gene Editing as "Food Security" from the Global South's Perspective

It is symbolic that EMBRAPA, a Brazilian public research institution, is at the center of this research team. Brazil, while being an agricultural powerhouse supporting the world's food supply with soybeans, corn, coffee, etc., is exposed to the impacts of climate change and the expansion of pests and diseases.

For Global South countries, technologies to "ensure yield while reducing pesticide dependence" are urgent issues. This is