Since it was first recognized in bacteria and archaea as a mechanism for innate viral immunity in the early 2010s, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) has rapidly been developed into a robust, multifunctional genome editing tool with many uses. Following the discovery of the initial CRISPR/Cas-based system, the technology has been advanced to facilitate a multitude of different functions. These include development as a base editor, prime editor, epigenetic editor, and CRISPR interference (CRISPRi) and CRISPR activator (CRISPRa) gene regulators. It can also be used for chromatin and RNA targeting and imaging. Its applications have proved revolutionary across numerous biological fields, especially in biomedical and agricultural improvement. As a diagnostic tool, CRISPR has been developed to aid the detection and screening of both human and plant diseases, and has even been applied during the current coronavirus disease 2019 (COVID-19) pandemic. CRISPR/Cas is also being trialed as a new form of gene therapy for treating various human diseases, including cancers, and has aided drug development. In terms of agricultural breeding, precise targeting of biological pathways via CRISPR/Cas has been key to regulating molecular biosynthesis and allowing modification of proteins, starch, oil, and other functional components for crop improvement. Adding to this, CRISPR/Cas has been shown capable of significantly enhancing both plant tolerance to environmental stresses and overall crop yield via the targeting of various agronomically important gene regulators. Looking to the future, increasing the efficiency and precision of CRISPR/Cas delivery systems and limiting off-target activity are two major challenges for wider application of the technology. This review provides an in-depth overview of current CRISPR development, including the advantages and disadvantages of the technology, recent applications, and future considerations.

Non-coding RNAs (ncRNAs) have emerged as critical components of gene regulatory networks across a plethora of plant species. In particular, the 20–30 nucleotide small ncRNAs (sRNAs) play important roles in mediating both developmental processes and responses to biotic stresses. Based on variation in their biogenesis pathways, a number of different sRNA classes have been identified, and their specific functions have begun to be characterized. Here, we review the current knowledge of the biogenesis of the primary sRNA classes, microRNA (miRNA) and small nuclear RNA (snRNA), and their respective secondary classes, and discuss the roles of sRNAs in plant–pathogen interactions. sRNA mobility between species is also discussed along with potential applications of sRNA–plant–pathogen interactions in crop improvement technologies.

Sorghum (Sorghum bicolor L. Moench) is one of the world's most cultivated cereal crops. Biotechnology approaches have great potential to complement traditional crop improvement. Earlier studies in rice and maize revealed that LIGULELESS‐1 (LG1) is responsible for formation of the ligule and auricle, which determine the leaf inclination angle. However, generation and analysis of lg1 mutants in sorghum has so far not been described. Here, we describe CRISPR/Cas9 mediated targeted mutagenesis of LG1 in sorghum and phenotypic changes in mono‐ and bi‐allelic lg1 mutants. Genome editing reagents were co‐delivered to sorghum (var. Tx430) with the nptII selectable marker via particle bombardment of immature embryos followed by regeneration of transgenic plants. Sanger sequencing confirmed a single nucleotide insertion in the sgRNA LG1 target site. Monoallelic edited plantlets displayed more upright leaves in tissue culture and after transfer to soil when compared to wild type. T1 progeny plants with biallelic lg1 mutation lacked ligules entirely and displayed a more severe reduction in leaf inclination angle than monoallelic mutants. Transgene‐free lg1 mutants devoid of the genome editing vector were also recovered in the segregating T1 generation. Targeted mutagenesis of LG1 provides a rapidly scorable phenotype in tissue culture and will facilitate optimization of genome editing protocols. Altering leaf inclination angle also has the potential to elevate yield in high‐density plantings.

No abstract

Sorghum is a versatile crop with great potential as a sustainable food, feed, and bioenergy source. To mitigate the severely negative impact of climate change and population growth on food and energy security, further elevation of the crops stress tolerance is urgently needed. Genome editing technologies such as CRISPR/Cas have great potential to accelerate functional genomics and crop improvement by supporting targeted modification of almost any crop gene sequence. We describe the recent progress in genome editing of sorghum. In addition, we review remaining challenges and prospects of emerging gene editing technologies for rapid precision breeding of this crop.