Can CRISPR help ease climate change food insecurity in Africa?

The Takeaway: Food insecurity is a staggering problem in Africa, where small farms struggle to adapt and climate change is making seasonal rains less and less predictable. Climate change exacerbates biotic and abiotic stresses such as alkaline soil, nutrient deficiency, pests, weeds, and pathogens. A new study shows how CRISPR-Cas9 is being used to help smallholder farms improve crop breeding to produce food that is resilient to the challenges of climate change. Let’s investigate.

How is food insecurity a problem in Africa?

Food insecurity in Africa is a complex issue with multiple causes, including environmental, social, political, and economic factors. Food insecurity can come and go as countries face hardships and then recover; currently, hunger is acute in Kenya, Nigeria, Ethiopia, and Somalia. Here are some key reasons why food insecurity persists in many parts of Africa:

Climate change and environmental degradation: Africa is particularly vulnerable to the impacts of climate change, including droughts, floods, and unpredictable weather patterns. These events can devastate agricultural production, leading to crop failures and food shortages.

Poor agricultural infrastructure: Many African countries lack the necessary infrastructure for efficient and sustainable agricultural production. This includes inadequate irrigation systems, limited access to modern farming techniques and technologies, and a lack of storage and transportation facilities. As a result, farmers struggle to maximize yields and mitigate the effects of environmental challenges.

Conflict and instability: Conflict and political instability are major drivers of food insecurity in several African regions. Armed conflicts disrupt agricultural activities, displace populations, and undermine food distribution networks. Additionally, displaced people often lose access to their land and livelihoods, exacerbating their vulnerability to food insecurity.

Poverty and inequality: High levels of poverty and income inequality contribute to food insecurity in Africa. Many people lack the financial resources to purchase an adequate and nutritious diet, while disparities in wealth distribution limit access to food among vulnerable populations.

Population growth: Rapid population growth in Africa puts pressure on food production and distribution systems. As the population continues to increase, the demand for food rises, placing additional strain on already limited resources.

Limited access to markets: In remote rural areas, limited access to markets and poor transportation infrastructure make it difficult for farmers to sell their produce and for consumers to access affordable food. This isolation exacerbates food insecurity in these regions. Instead of selling thousands of pounds of tomatoes in one exchange, farmers often sell a literal handful of tomatoes at a time at roadside stalls.

Health challenges: Health issues such as HIV/AIDS, malaria, and other infectious diseases can undermine food security by reducing agricultural productivity, increasing healthcare costs, and weakening household resilience.

Addressing food insecurity in Africa requires a comprehensive approach that addresses these underlying causes. This may include investments in agricultural development, infrastructure improvement, conflict resolution and peacebuilding efforts, poverty reduction strategies, and policies that promote sustainable and equitable access to food resources.

How does climate change worsen food insecurity in Africa?

Climate change exacerbates food insecurity in Africa in myriad ways, including:

Erratic weather: Climate change leads to increased frequency and severity of extreme weather events, such as droughts, floods, and storms. These events disrupt agricultural production, destroy crops, and damage infrastructure, leading to reduced yields and food shortages.

Decreased agricultural productivity: Rising temperatures, changes in precipitation patterns, and increased frequency of pests and diseases can reduce agricultural productivity. Crops may fail to mature or suffer from heat stress, leading to diminished yields and income for farmers.

Water scarcity: Climate change exacerbates water scarcity in many parts of Africa, particularly in arid and semi-arid regions. Droughts reduce water availability for irrigation, livestock, and domestic use, further compromising agricultural production and food security.

Shifts in crop suitability: Changes in temperature and rainfall patterns can alter the suitability of certain crops for specific regions. Traditional crops may become less viable, while new pests and diseases may emerge, affecting crop yields and food availability.

Loss of livelihoods: Climate-related disasters such as floods and droughts can result in loss of livelihoods for farmers and rural communities. Crop failures and livestock losses may force people to migrate in search of alternative sources of income, exacerbating food insecurity and placing additional pressure on urban areas.

Impact on fisheries and livestock: Climate change affects not only crop production but also fisheries and livestock farming. Rising sea temperatures and ocean acidification can disrupt marine ecosystems, reducing fish stocks and threatening the livelihoods of coastal communities. Similarly, changes in temperature and precipitation patterns can affect the availability and quality of pastureland for livestock grazing.

Increased vulnerability of marginalized communities: Marginalized and vulnerable populations, such as smallholder farmers, women, and indigenous communities, are disproportionately affected by climate change due to limited resources, lack of access to information and technology, and social inequalities. These communities often have fewer options to cope with climate-related shocks, further exacerbating food insecurity.

The small size of most African farms exacerbates these problems

The majority of farms in Africa are smallholder farms. Smallholder farms are typically characterized by their relatively small size, limited resources, and reliance on family labor. These farms often operate on a subsistence basis, meaning they primarily grow crops for their own consumption and may sell surplus produce locally. Forget industrial ag operations: in Africa, most farms are a few acres.

Several factors contribute to the prevalence of smallholder farms in Africa including historical contexts, land distribution and access, limited resources, subsistence agriculture, and market access challenges. Despite their prevalence, smallholder farms play a crucial role in African agriculture and food security.

How can CRISPR improve crop yields and crop resilience?

CRISPR, which stands for clustered regularly interspaced short palindromic repeats, is a revolutionary gene-editing technology that allows scientists to make precise changes to an organism's DNA. It's derived from the natural defense mechanisms of bacteria against viruses. CRISPR uses Cas9, often referred to as CRISPR-associated protein 9, an enzyme that plays a central role in the CRISPR-Cas9 gene-editing system. It's a type of nuclease with the ability to cut DNA strands at specific locations. Cas9 is derived from bacteria and archaea, where it acts as part of the natural defense mechanism against viruses.

In the CRISPR-Cas9 system, Cas9 works in conjunction with guide RNA to locate and cut specific sequences of DNA. The gRNA is designed to complement the target DNA sequence, guiding Cas9 to the precise location for gene editing.

CRISPR also uses Cas12a ultra, a high purity, recombinant Lachnospiraceae bacterium ND2006 nuclease purified from an E. coli strain. It can be used to express Cas12a to improve both on-target performance and temperature tolerance.

CRISPR technology holds promise for improving crop yields by enabling precise genetic modifications that can enhance desirable traits in plants. Here are several ways CRISPR can contribute to improving crop yields:

Disease resistance: CRISPR can be used to introduce genetic changes that confer resistance to plant diseases caused by viruses, bacteria, fungi, and other pathogens. By targeting genes involved in disease susceptibility, researchers can develop crops that are more resilient to pests and diseases, leading to higher yields.

Pest resistance: Similarly, CRISPR can be employed to create crops with enhanced resistance to insect pests. By modifying genes associated with pest susceptibility or introducing genes from naturally pest-resistant species, scientists can develop crops that require fewer chemical pesticides and suffer less damage from pests, resulting in increased yields.

Abiotic stress tolerance: CRISPR can help develop crops that are more resilient to abiotic stresses such as drought, heat, salinity, and cold. By editing genes involved in stress response pathways or introducing genes from stress-tolerant species, researchers can enhance the ability of crops to withstand challenging environmental conditions, thereby improving yields in adverse growing conditions.

Improved nutritional content: CRISPR can be utilized to enhance the nutritional content of crops, making them more nutritious and potentially improving human health outcomes. For example, researchers can use CRISPR to increase the levels of vitamins, minerals, antioxidants, or other beneficial nutrients in staple crops, leading to improved nutritional quality and potentially higher yields due to improved crop performance.

Optimized growth and development: CRISPR can facilitate the modification of genes involved in plant growth, development, and physiology, allowing researchers to optimize crop traits such as yield potential, flowering time, fruit size, and overall plant architecture. By fine-tuning these traits, scientists can develop crops that are more productive and efficient in utilizing available resources, leading to increased yields.

Reduction of yield-limiting factors: CRISPR can target genes responsible for factors that limit crop yields, such as plant height, branching patterns, or seed shattering. By modifying these genes, researchers can develop crops with improved agronomic traits that minimize yield losses during cultivation and harvesting.

CRISPR crop-editing successes

CRISPR has already made big strides in helping to alleviate many of these problems, according to a recent article in Nature. The article, by a team of researchers from Zimbabwe and Kenya, noted many of these gains:

• Genome editing of three cereal crops—wheat, maize, and rice—to increase production in light of heat stress and water limitations
• Genome editing of legumes such as cowpea and soybean to withstand extreme drought and high temperatures
• Use of CRISPR-Cas9 to engineer banana varieties that resist a bacterial disease prevalent in east Africa
• Use of CRISPR-Cas9 to create sorghum that resists a parasitic weed
• Development of a maize breed that resists maize lethal necrosis without altering desirable traits
• Gene editing of cassava to significantly reduce the presence of naturally occurring cyanide
• Use of CRISPR to reduce the level of erucic acid in Ethiopian mustard oil

“Smallholder agricultural systems will be dramatically and unpredictably impacted by climate change,” the authors wrote. “By breeding varieties that increase the resilience of smallholder farms to climate change, plant improvement is upheld as a key element of adapting agricultural systems to it.”

Download our CRISPR Basics Handbook

CRISPR is rapidly changing the worlds of medicine, agriculture, and more. It’s a complicated, evolving technology, but we’ve worked hard to making understanding it easier with our CRISPR Basics Handbook. This free comprehensive guide includes a brief history of CRISPR, an overview of common applications, instructions for how to get started, design and enzyme guidelines and considerations, and more.

Download the handbook here.