Genome editing in Sub-Saharan Africa: a game-changing strategy for climate change mitigation and sustainable agriculture

Abstract

Sub-Saharan Africa's agricultural sector faces a multifaceted challenge due to climate change consisting of high temperatures, changing precipitation trends, alongside intensified pest and disease outbreaks. Conventional plant breeding methods have historically contributed to yield gains in Africa, and the intensifying demand for food security outpaces these improvements due to a confluence of factors, including rising urbanization, improved living standards, and population growth. To address escalating food demands amidst urbanization, rising living standards, and population growth, a paradigm shift toward more sustainable and innovative crop improvement strategies is imperative. Genome editing technologies offer a promising avenue for achieving sustained yield increases while bolstering resilience against escalating biotic and abiotic stresses associated with climate change. Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein (CRISPR/Cas) is unique due to its ubiquity, efficacy, alongside precision, making it a pivotal tool for Sub-Saharan African crop improvement. This review highlights the challenges and explores the prospect of gene editing to secure the region's future foods.

Keywords: CRISPR/Cas9; Climate resilience; crop Improvement; food security; gene editing; plant breeding; sustainable agriculture.

Figure 1.

The general workflow for gene editing technologies to engineer disease resistance in crops, (a) general structure of the viral genome; target single-strand RNAs (sgRNAs) containing putative sequences are displayed in red for the replication-associated protein (Rep), intergenic region (IR), and viral capsid protein (CP) regions of the viral genome. CRISPR/Cas9 can be used to execute a multiplex genome editing technique based on multiplex sgRNA targeting IR, CP, and Rep of several viruses. (b) A diagram illustrating three methods for modifying the genome that give plants immunity against genomic alterations at specific sites. Bacterial or viral genomes undergo induced mutagenesis, which makes them ineffective. (c) Agrobacterium tumefaciens T-DNA producing reporter gene (GFP) under CaMV promoter, Cas9 protein under CaMV promoter, and sgRNA under CaMV promoter. (d) Plant cell agroinfiltration, which involves injecting an Agrobacterium bearing an engineered virus into a Cas9-expressing plant to express the target virus’s sgRNA. (e) Editing the genome of genes or transcription factors to adversely regulate a plant’s resistance to bacterial, viral, or fungal infections by deleting certain base pairs, followed by the cultivation of a resistant plant by tissue culture methods.

Figure 2.

Diagram illustrating how zinc finger nucleases (ZFNs) are used to alter the plant genome: target specificity is achieved by zinc finger arrays connected to FoKI endonuclease.

Figure 3.

Diagram illustrating how the transcription activator-like effector nucleases (TALENs) are used to modify the plant genome. There are 13–28 transcriptional activator like effector repeats (TALE repeats) in the DNA binding domain of TALENs. Sticky DSBs are produced by TALENs.

Figure 4.

Diagram illustrating how the CRISPR/Cas9 is utilized to alter the plant genome. Leveraging on HNH and RuvC domains, the Cas9 nuclease aims at the complementary and non-complementary DNA to create a blunt end DSB.