Genome editing in maize: Toward improving complex traits in a global crop

Abstract

Recent advances in genome editing have enormously enhanced the effort to develop biotechnology crops for more sustainable food production. CRISPR/Cas, the most versatile genome-editing tool, has shown the potential to create genome modifications that range from gene knockout and gene expression pattern modulations to allele-specific changes in order to design superior genotypes harboring multiple improved agronomic traits. However, a frequent bottleneck is the delivery of CRISPR/Cas to crops that are less amenable to transformation and regeneration. Several technologies have recently been proposed to overcome transformation recalcitrance, including HI-Edit/IMGE and ectopic/transient expression of genes encoding morphogenic regulators. These technologies allow the eroding of the barriers that make crops inaccessible for genome editing. In this review, we discuss the advances in genome editing in crops with a particular focus on the use of technologies to improve complex traits such as water use efficiency, drought stress, and yield in maize.

Viral delivery of CRISPR/Cas9 genome editing for rapid crop improvement: A promising approach to enhance crop resilience against biotic and abiotic stresses

“…For instance, researchers have successfully utilized viral delivery of CRISPR/Cas9 to create maize plants with stacked traits of disease resistance, insect tolerance, and improved drought tolerance. By editing specific genes associated with each trait, they generated ~ 786 ~ transgenic maize varieties capable of withstanding insect attacks, resisting common diseases, and maintaining productivity under limited water availability (Hernandes-Lopes et al, 2023) [48] Moreover, viral delivery of CRISPR/Cas9 has shown the potential to target multiple genes involved in different metabolic pathways. This capability has been exemplified in the development of biofortified crops with enhanced nutritional value.…”

Enabling genome editing in tropical maize lines through an improved, morphogenic regulator-assisted transformation protocol

“…CRISPR/Cas9-based targeted mutagenesis has been shown to be a promising tool for GE in maize, allowing manipulation of genes underlying agronomic traits, including complex traits controlled by multiple genes ( Hernandes-Lopes et al, 2023 ). However, bringing such approaches to a commercial scale is difficult.…”

“…Transformation recalcitrance of most maize genotypes, from temperate and tropical origins, is the main bottleneck for applying biotechnological solutions to this crop. In addition, most GE studies in maize are limited to temperate genotypes suitable for Agrobacterium tumefaciens -mediated transformation, such as the public inbred line B104 ( Kausch et al, 2021 ; Yassitepe et al, 2021 ; Hernandes-Lopes et al, 2023 ). Therefore, the lack of genotypes both adapted to different agroecological zones and amenable to GE technologies is a significant limitation to maize improvement efforts in tropical and subtropical regions, which encompass developing countries most impacted by global climate change ( Anderson et al, 2020 and references therein).…”

“…Despite the growing number of publications on improved maize transformation and GE technologies, successful reports on tropical maize lines have been less numerous than those on their temperate counterparts ( Rangari et al, 2023 ; Souza et al, 2017 ; reviewed by Hernandes-Lopes et al, 2023 ; Yadava et al, 2017 ). Thus, in the present study, we applied the MR-based approach previously used by Aesaert et al (2022) for optimized B104 transformation and GE to different tropical maize lines.…”