Deleterious mutation burden and its association with complex traits in sorghum (sorghum bicolor)

Authors: VALLURU, RAVI - Cornell University; GAZAVE, ELODIE - Cornell University; FERNANDES, SAMUEL - University Of Illinois; FERGUSON, JOHN - University Of Illinois; LAZANO, ROBERTO - Cornell University; HIRANNAIAH, PRADEEP - University Of Illinois; ZUO, TAO - Cornell University; BROWN, PATRICK - University Of California, Davis; LEAKEY, ANDREW - University Of Illinois; GORE, MICHAEL - Cornell University; Buckler, Edward - Ed; BANDILLO, NONOY - Cornell University

Submitted to: Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2018
Publication Date: 3/1/2019
Citation: Valluru, R., Gazave, E., Fernandes, S., Ferguson, J., Lazano, R., Hirannaiah, P., Zuo, T., Brown, P., Leakey, A., Gore, M., Buckler IV, E.S., Bandillo, N. 2019. Deleterious mutation burden and its association with complex traits in sorghum (sorghum bicolor). Genetics. 211(3):1075-1087. https://doi.org/10.25386/genetics.7638122.
DOI: https://doi.org/10.25386/genetics.7638122

Interpretive Summary: Sorghum (Sorghum bicolor L.) is a major food cereal for millions of people worldwide. The sorghum genome, like other species, accumulates deleterious mutations, likely impacting its fitness. The lack of recombination, drift, and the coupling with favorable loci impede the removal of deleterious mutations from the genome by selection. To study how deleterious variants impact phenotypes, we identified putative deleterious mutations among ~5.5 M segregating variants of 229 diverse biomass sorghum lines.

Technical Abstract: We used phenotypic and genomic data from different racial groups of sorghum to show that sorghum accumulates an appreciable number of deleterious mutations in the genome. Mutation burden differs substantially among racial groups that negatively correlate with phenotypes. GS models encompassing deleterious mutations show variable predictive ability across traits and, given the relatively high level of population structure in sorghum, disentangling deleterious effects at the single-variant level would take a tremendous amount of effort and recombination. Deleterious variants could be prioritized through work with intermediate phenotypes or with more extensive evolutionary analysis among closely related species. Both of these avenues, if combined with high-throughput genome editing and conventional breeding approaches involving parental lines with fewer deleterious variants, could be used to systematically start removing deleterious variants from elite sorghum lines.