Genome Engineering

Abstract

Root and tuber crops consist of starchy staples from botanically diverse groups critically contributing to food security and income generation. More than 30 species of root and tuber crops are cultivated worldwide with cassava (Manihot esculanta Crantz), sweet potato (Ipomoea batatas L.), yam (Dioscorea spp.), potato (Solanum tuberosum L.), taro (Colocosia esculenta) and cocoyam (Xanthosoma sagittifolium) being predominant species with respect to cultivation and utilization. They constitute major staples in most countries providing more edible energy per hectare per day compared to other crops as well as contributing towards food security and adaptation to climate change. Like most other crops, production and utilization of root and tuber crops are impacted by various factors including diseases, pests, post-harvest deterioration, deficiencies in one or more essential nutrients and yield. Robust and resilient varieties of some of these crops such as cassava, yam and sweet potato have been bred conventionally, while crops like cocoyam and potato have received very little attention from the scientific world, partly due to low genetic base and parents for breeding programmes. Genetic engineering has also contributed immensely to the development of new varieties of root and tuber crops, even though there are limitations particularly as it relates to complexity associated with manipulation of large and complicated genomes found in higher plants. Recently, tools that enable targeted transgene integration or precise genome editing are available to mitigate the challenges associated with genetic engineering of most plant species and thus provide a new frontier for root and tuber crops improvement. Recent trends have shown tremendous generation of genomic resources including annotated genomic sequences, transcriptomic data and genetic map of most plant species and crops. This is essential for the deployment of genome engineering for improvement of root and tuber crops. This chapter aims at evaluating the genomic resources and plant transformation technologies available for improvement of root and tuber crops, the regulatory machineries associated with genome editing and the way forward.