Gene editing will revolutionize crop breeding in Africa, new paper predicts

by Joseph Opoku Gakpo

April 21, 2020

Genome editing technology has the potential to revolutionize crop development on the African continent, especially in sub-Sahara Africa, according to a new scientific paper.

The paper, published in the Frontiers in Plant Science Journal by John Komen and five other scientists working in Africa, noted that CRISPR-Cas9 is already being used to improve major staple foods in Africa, such as wheat, cassava and banana, among others, and the research results are looking promising. International agricultural research centers, in collaboration with national research organizations in Africa, also are adopting genome editing in their research and development programs, the paper said.

Komen urged African governments and research organizations to “act now to ensure they can access and apply these new technologies to the most pressing needs in their own countries.”

Research is already under way in a number of African countries.  The Kenya Agriculture and Livestock Research Organization (KALRO) and two other international organizations are using CRISPR-Cas9 technology to improve maize germplasm so it becomes resistant to maize lethal necrosis (MLN), a devastating viral disease in plants.

MLN first appeared in Kenya in 2011 and has since spread to several countries in East Africa. In 2013, the disease reduced maize yields in Kenya by an average of 22 percent and forced many farmers to abandon planting the staple crop. The situation cost the country’s agricultural sector a whopping US$180 million.

The International Maize and Wheat Improvement Center and partners have developed MLN-tolerant hybrids through conventional breeding. But the process is resource-intensive and takes about four-to-five years. The MLN Gene Editing Project is accelerating the process, helping to reduce breeding time to two-to-three years so farmers can get improved planting materials faster. Similar work is ongoing on wheat germplasm.

In banana, a team of scientists from the International Institute of Tropical Agriculture (IITA) has used CRISPR/Cas9-based genome editing to inactivate the endogenous banana streak virus (eBSV) integrated in the host genome of infected plants. This made the resulting plant highly resistant to the virus.

“This strategy can be applied to improve breeding lines, which can then be used to develop plantain hybrids with no risk of activation of functional virus,” explained Leena Tripathi, a banana transformation specialist leading the project, in an interview with IITA news.

Banana streak virus was first detected in Cote D’Ivoire about 50 years ago and has since spread to tens of tropical countries. It causes streaks to form on the leaves before destroying the stem and eventually killing the plant. Scientists hope to stem its spread using gene editing technology.

The IITA is also developing banana varieties resistant to the bacterial wilt and fusarium wilt diseases using CRISPR/Cas9. The technology is also being used to develop cassava varieties with enhanced resistance to the cassava brown streak disease (CBSD), a viral disease that has caused extensive crop failures in Africa.

“The greatest potential advantages of new breeding technologies, including genome editing in agriculture, are their relative ease, precision, speed and low cost, allowing plant breeders to focus more on the local growing conditions and to react more quickly to the changing needs and wants of growers and consumers,” lead author Komen told the Alliance for Science in an interview.

He noted that “the current global research and development pipeline for genome edited crops, for example, shows a much wider range of relevant crops and traits being targeted” than those developed through earlier genetic modification techniques.

Policy discussions on genome editing are only just starting in Africa, but rapidly gaining traction across the continent, he said.

“Ongoing discussions under the Convention on Biological Diversity (CBD)’s Cartagena Protocol on Biosafety and within the African Union are contributing to the conversation,” Komen noted. “A growing body of literature shows the importance of adding genome editing to the research toolbox, particularly for enhancing resilience and productivity in African agriculture in the face of a growing population.”

Komen noted that African nations are preparing to introduce genome editing techniques and some countries, like Nigeria, have already amended their biosafety laws to incorporate these new breeding techniques. Additionally, African countries without specific gene editing provisions in their laws have functional regulatory frameworks, supported by clear guidelines, that can cover applications of genome editing that result in products with a “novel combination of genetic material.”

Meanwhile, global expertise regarding genome editing and science-based approaches to its regulation are developing rapidly, which will benefit regulators in Africa as well, he added.