Sequenced Sorghum Mutant Library As a Genomic Resource for Rapid Discovery of Causal SNPs for Agronomic Traits.

As the filth largest grain crop in the world, sorghum is well adapted to high temperature, drought, and low fertilizer input conditions. It can also be used as a fodder and bioenergy crop. Given the trend of global warming, depletion of refresh water resources, reduction in arable land due to soil degradation and urban development, and the increasing demand for food, feed, and bioenergy, sorghum is likely to become an increasingly important crop for meeting the future demand for agricultural products while preserving the sustainability of the essential agricultural resources. To accelerate the genetic improvement of sorghum for multiple end-uses, we have developed a pedigreed mutant library consisting of 6,400 M4 seed pools, each derived from an independently mutagenized seed from the inbred line BTx623. The mutant library displays a wide range of phenotypical variations, including many traits that can be directly used for breeding. To link the EMS-induced mutations and the phenotypes, we conducted whole genome sequencing of 256 M3 generation mutants at approximately 15x coverage. From the 3Tb of sequencing data, we identified 1.5 million high confidence GCàAT SNPs, about 1 change every 475 bases. A total of 16.24% of the SNPs are located in 30,690 genes, which is about 92.91% of Sorghum genes. Among these genes, we found 23,329 (70.63%) with missense or stop-gained SNPs in the population, which have the potential to cause large phenotypic changes. This large-scale sequenced mutant library will be a useful forward and reverse genetic resource for in sillico identification and genes underlying important traits and mutant series for interesting genes to elucidate their function in sorghum plants.