A comprehensive omics resource and genetic tools for functional genomics research and genetic improvement of sorghum

Sorghum, the fifth most important food crop globally, is a source of silage forage, fiber, syrup, and biofuel. Moreover, it is widely recognized as an ideal model crop for studying stress biology becaused of its ability to tolerate multiple abiotic stresses, including high salt-alkali conditions, drought, and heat. However, functional genomics studies on sorghum have been challenging, primarily due to the limited availability of genetic resources and effective genetic transformation techniques. In this study, we developed the Sorghum Genomics and Mutation Database (SGMD), aiming to advance the genetic understanding of sorghum. Our effort encompassed a telomere-to-telomere genome assembly of an inbred sorghum line, E048, yielding 729.46 Mb of sequence data representing the complete genome. Alongside the high-quality sequence data, a gene expression atlas covering 13 distinct tissues was developed. We constructed a saturated ethyl methane sulfonate mutant library comprising 13,226 independent mutants. Causal genes in chlorosis and leafy mutants from the library were easily identified by leveraging the MutMap and MutMap+ methodologies, demonstrating the powerful application of this library for identifying functional genes. To facilitate sorghum research, we performed whole-genome sequencing of 179 M₂ mutant lines, resulting in 2,291,074 mutations that covered 97.54% of all genes. In addition, an Agrobacterium-mediated sorghum transformation platform was established for gene function studies. In summary, this work establishes a comprehensive platform and provides valuable resources for functional genomics investigations and genetic improvement of sorghum.