A large sequenced mutant library – valuable reverse genetic resource that covers 98% of sorghum genes.

Jiao Y, Nigam D, Barry K, Daum C, Yoshinaga Y, Lipzen A, Khan A, Parasa SP, Wei S, Lu Z, Tello-Ruiz MK, Dhiman P, Burow G, Hayes C, Chen J, Brandizzi F, Mortimer J, Ware D, Xin Z

Published: 15 December 2023 in The Plant journal : for cell and molecular biology
Keywords: ethyl methyl sulfone mutants, resequencing, sorghum
Pubmed ID: 38100514
DOI: 10.1111/tpj.16582

Mutant populations are crucial for functional genomics and discovering novel traits for crop breeding. Sorghum, a drought and heat-tolerant C4 species, requires a vast, large-scale, annotated, and sequenced mutant resource to enhance crop improvement through functional genomics research. Here, we report a sorghum large-scale sequenced mutant population with 9.5 million ethyl methane sulfonate (EMS)-induced mutations that covered 98% of sorghum's annotated genes using inbred line BTx623. Remarkably, a total of 610 320 mutations within the promoter and enhancer regions of 18 000 and 11 790 genes, respectively, can be leveraged for novel research of cis-regulatory elements. A comparison of the distribution of mutations in the large-scale mutant library and sorghum association panel (SAP) provides insights into the influence of selection. EMS-induced mutations appeared to be random across different regions of the genome without significant enrichment in different sections of a gene, including the 5' UTR, gene body, and 3'-UTR. In contrast, there were low variation density in the coding and UTR regions in the SAP. Based on the Ka /Ks value, the mutant library (~1) experienced little selection, unlike the SAP (0.40), which has been strongly selected through breeding. All mutation data are publicly searchable through SorbMutDB (https://www.depts.ttu.edu/igcast/sorbmutdb.php) and SorghumBase (https://sorghumbase.org/). This current large-scale sequence-indexed sorghum mutant population is a crucial resource that enriched the sorghum gene pool with novel diversity and a highly valuable tool for the Poaceae family, that will advance plant biology research and crop breeding.