CRISPR/Cas Systems for Enhancing Photosynthesis: Climate Resilience and Food Production

To achieve the Sustainable Development Goal 2 (SDG 2) established by the UN, there is a need to produce 15–20% more food from recent trends of production. Biotechnological advances in the late twentieth century paved the path for the creation of genetically engineered crop species to enhance agricultural production. Recently programmable gene editing tools such as zinc-finger nucleases (ZFN), transcription activator-like effector (TALE) nucleases, clustered regularly interspaced short palindromic repeat (CRISPR) systems, and base editors have been developed to edit any genome for desirable traits. Furthermore, plant organelle genomes are distinct, encoding numerous genes crucial for photosynthesis and respiration. Any alteration in photosynthetic functionality can directly impact crop production. Photosynthesis enzymes are evolutionarily conserved in green plants. There is huge scope for CRISPR in plant genomics to transform routine crops into superfoods. Chloroplast-targeting editing with a magic cut of CRISPR allows the engineering of food crops with higher expression of useful traits such as increased traits of specific types of oil content in seeds or inclusion of all essential vitamins in plant-based diets. Knock-out or knock-in genes, especially those related to photosystem or engineering of small subunits of the key CO2-fixing enzyme Rubisco (SSU-encoded by rbcS) or plant disease—resistance or genes of any other intermediate metabolites in plants can facilitate high productivity even under climate change scenario. CRISPR-Cas9 enables the editing of multiple genes in polyploid species which have remained challenging for a long time. Supercharging C3 plants with advancement in the photosynthesis process allows more production of calories in limited land area and fertilizer. In this review, we address the advances in CRISPR-Cas9-based editing uses, challenges and scope to improve photosynthesis and related targeted genes to enhance the efficiency of crop plants.