Progress and challenges in sorghum biotechnology, a multipurpose feedstock for the bioeconomy.

Sorghum [Sorghum bicolor (L.) Moench] is the fifth most important cereal crop globally by harvested area and production. Its drought and heat tolerance allow high yields with minimal input. It is a promising biomass crop for the production of biofuels and bioproducts. In addition, as an annual diploid with a relatively small genome compared with other C4 grasses, and excellent germplasm diversity, sorghum is an excellent research species for other C4 crops such as maize. As a result, an increasing number of researchers are looking to test the transferability of findings from other organisms such as Arabidopsis thaliana and Brachypodium distachyon to sorghum, as well as to engineer new biomass sorghum varieties. Here, we provide an overview of sorghum as a multipurpose feedstock crop which can support the growing bioeconomy, and as a monocot research model system. We review what makes sorghum such a successful crop and identify some key traits for future improvement. We assess recent progress in sorghum transformation and highlight how transformation limitations still restrict its widespread adoption. Finally, we summarize available sorghum genetic, genomic, and bioinformatics resources. This review is intended for researchers new to sorghum research, as well as those wishing to include non-food and forage applications in their research.

Nanotechnology to advance CRISPR-Cas genetic engineering of plants.

CRISPR-Cas genetic engineering of plants holds tremendous potential for providing food security, battling biotic and abiotic crop stresses caused by climate change, and for environmental remediation and sustainability. Since the discovery of CRISPR-Cas technology, its usefulness has been demonstrated widely, including for genome editing in plants. Despite the revolutionary nature of genome-editing tools and the notable progress that these tools have enabled in plant genetic engineering, there remain many challenges for CRISPR applications in plant biotechnology. Nanomaterials could address some of the most critical challenges of CRISPR genome editing in plants through improvements in cargo delivery, species independence, germline transformation and gene editing efficiency. This Perspective identifies major barriers preventing CRISPR-mediated plant genetic engineering from reaching its full potential, and discusses ways that nanoparticle technologies can lower or eliminate these barriers. We also describe advances that are needed in nanotechnology to facilitate and accelerate plant genome editing. Timely advancement of the application of CRISPR technologies in plant engineering is crucial for our ability to feed and sustain the growing human population under a changing global climate.