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CRISPR-Cas9 technology to boost the consumption of functional foods 06 Feb 2024

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and their associated protein (Cas-9) can make a significant difference to how people consume functional foods. Functional foods are dietary items that beneficially enhance certain physiological responses in the body by reducing the risk of diseases in addition to providing nutrients. Some of these food items naturally possess unpleasant attributes together with their nutritional and health-promoting properties.

I enjoy adding a lot of onion to season my meat and fish, and as a condiment to my soup, stew, egg sauce, and others to enhance flavour and for its numerous nutritive effects. Onions can also be added as toppers to salads and barbecue for consumption without cooking. Apart from helping to tenderise meat and improve taste, onions are rich in vitamins and minerals such as vitamin C, vitamin B6, manganese, potassium, and copper, among others.

Onions are also one of the greatest sources of quercetin – a flavonoid that acts as an antioxidant, helping to mop up free radicals whose accumulation has been linked to the aetiology of several disease conditions like cancers, diabetes, heart diseases and others. But onions have a pungent and teary sensation that quenches my desire to slice as much as I require for consumption. The tears that accompany each slice is certainly a common deterrent for the use of onions. And that brings the thought of having onions that do not release the volatile liquid called propanethial-S-oxide, which irritates the eyes and causes the release of tears when the plant cell wall is damaged after onion is cut.

A similar effect is observed with very hot peppers, especially locally grown scotch bonnet pepper, popularly called ‘ata rodo’ in Yoruba. When grinding, heating, or cooking, scotch bonnet pepper produces intense spicy fumes causing nasal irritation, sneezing and coughing. The irritation can be a deterrent to its use. We want to have the spicy attribute of scotch bonnet pepper without its accompanied irritations.

In order to satisfy consumers and make food preparation and consumption more enjoyable, scientists have developed a number of approaches and continue to improve on them to alter natural components in food crops for the benefit of humans and our planet. Aside ensuring consumer satisfaction, such modifying approaches in crops have become necessary to tackle phenomena that limit our ability to produce enough food including functional foods for the world’s growing population.

These phenomena include climate change, which is charaterised by increases in temperature, changes in precipitation patterns, and extreme weather events that hinder agricultural productivity. Other conditions that such modifications seek to address include the excessive reliance on pesticides due to increased attack of pests and diseases on crops and abiotic stress conditions such as drought, salinity stress, and heavy metal stress as well as the need to increase yield using limited resources.

Some decades back, genetically modified (GM) foods were introduced through genetic engineering to fast-track the traditional selective and cross-breeding methods used to produce plants and animals with desirable traits. Both methods that have been conventionally used for hundreds of years bring about changes to the genetic makeup of target plants and animals. The major disadvantages of the traditional or conventional method of modifying crops by cross breeding, where pollen grains from one plant are collected and transferred to the pistil of another plant showing desirable characters, is that it is tedious and time consuming. It can take several years to successfully cross-plants and select improved varieties. Many times, undesirable traits are also transferred in the process.

Although the aim has basically been to improve crop yield generally, one aspect of genetic engineering for crop modification that has stirred disapproval is the idea of always having to introduce a foreign DNA from another organism, whether plant, animal, or microbe into the genome of the plant to be modified as we had in the modification of sweet corn with a bacteria called Bacillus thuringiensis. It was incorporated genetically into sweet corn in order to transfer the insecticidal properties of the protein crystal produced by B. thuringiensis to sweet corn. Up to 90 per cent reduction in pesticide use is possible because of this intervention. Similar procedure is carried out to improve other crops.

Since 1996, when the planting of insect resistant GM maize  was commercialised in South Africa, several GM crops have been grown such as GM rice, soybeans, cotton, pod borer-resistant GM cowpea for varying desirable traits. But apart from improving yield and making the process of producing food crops easier and cheaper, we must also make modifications to increase the intake of functional foods.

Another functional food ingredient is garlic. Garlic is used as a spice and flavouring ingredient. It has nutritional components – carbohydrates, protein, fat, minerals, water and vitamins as well as medicinal potentials due to the presence of allicin and its derivatives. It possesses wound healing activities, antioxidant, anti-inflammatory, ulcer inhibiting, rheumatological, analgesic, antimicrobial, antidiabetes, anticancer, liver protection activities and has also been reported to help with asthma, arthritis, chronic fever, runny nose, malaria, indigestion, enlarged spleen anemia, cataract and so on. As a biochemist, I am very much aware of the numerous health benefits of garlic, but I cannot stand its irritating smell. This is a setback to the use of some functional foods that needs to be addressed.

Moving forward, more interesting improvements have been developed in the quest to produce more food and make them more acceptable to consumers while retaining their health benefits. Scientists have been able to eliminate the need to always infuse a foreign DNA by introducing a process called gene editing. Technically, this modification does not involve the introduction of a new DNA/gene but re-arranging the plant’s own genes. One of the tools developed to successfully edit the gene of organisms which has also recently been applied to crops is CRISPR-Cas9.

CRISPR based genome editing can improve crop nutrients for food security. The Cas9 protein, which is a large multi-domain DNA endonuclease, recognises and cuts the target DNA (which produces the undesirable character in the plant) acting like a scissors. After cutting the DNA, researchers use the DNA repair mechanism of the plant itself to delete gene sequence responsible for production of proteins which gives certain undesirable characters to add pieces of genetic material to incorporate a desired attribute. Using the CRISPR editing tool, mustard greens, for example, have been engineered to be less bitter and more appetising to consumers without altering the nutritional benefits of the vegetable, in the United States of America.

Conducting field trials, ensuring safety for consumers, and eventually commercialising research innovations of this kind in Africa is certainly not a smooth ride despite their many benefits. For many reasons, including inadequate funding for research and development to localise such interventions, delays in passing biosafety rules and regulatory requirements, lack of political will to prioritise research for food security, poor advocacy and communication with stakeholders, Africa has a record of delayed adoption of new technologies and approaches already in use in other parts of the world that can help feed and nourish our teeming population.

For example, after 15 years of commencing field trials, Uganda is yet to bring a single modified crop to market. The same for Cameroon with 11 years of field trials, Ghana with 10 years of field trials, Tanzania and Mozambique with seven and six years respectively. The testing and adoption of CRISPR-Cas9 technology for editing plant genome should not take longer than necessary as we are having with GMOs.

As one of the continents contributing generously to global population, Africa should make more effort to be at the forefront of research endeavours that can help the continent feed itself sufficiently or at least have dedicated mechanisms to make adoption of safe and promising technologies hitch free. If this happens, we might be able to benefit more from the consumption of onions without tearing up, cooking with scotch bonnet without irritation, and even consuming bitter leaves that are less bitter. The genome of many other nutritious and health promoting spices and fruits can as well be edited for maximum satisfaction and improved outcome in challenging conditions.  

Mojisola Karigidi, PhD, a Financial Nigeria Columnist, is a Nigerian biochemist and the founder and product developer at Moepelorse Bio Resources. She is also a Global Innovation Through Science and Technology (GIST) awardee, and an Aspen New Voices fellow.