Genome-Wide Association Mapping Identifies an SNF4 Ortholog that Impacts Biomass, Plant Height, SSC and Juice Yield in Sorghum and Sugarcane

Sorghum is feed/industrial crop in the developed countries and a staple food in the rest of the world. In this study, we evaluated the sorghum mini core (MC) collection for days to 50% flowering (DF), biomass (BM), plant height (PH), soluble solid content (SSC) and juice weight (JW) and the sorghum reference set (RS) for DF and PH in 7-12 testing environments and performed association mapping with 6,094,317 SNP markers in the MC and 265,500 SNPs for the RS. We identified in the MC panel three QTLs for DF, one for PH, one for BM, and two for JW. In the RS panel we identified another PH QTL on chromosome 6 also associated with DF, BM, JW, and SSC in the MC panel. Transgenic studies of three genes selected from the locus revealed that Sobic.006G061100 (SbSNF4-2) increased BM, SSC, JW, and PH when overexpressed in both sorghum and sugarcane and delayed flowering in transgenic sorghum. SbSNF4-2 encodes a gamma subunit of the evolutionarily conserved AMPK/SNF1/SnRK1 heterotrimeric complexes and overexpression of human or mouse gamma 2 in heart or the whole body also increases heart or body biomass. SbSNF4-2 and its orthologs will be valuable in genetic enhancement of biomass and sugar yield in plants.

Automated summary

This study evaluated the sorghum mini core collection and performed association mapping, identifying QTLs associated with flowering time, biomass, plant height, and other traits. Transgenic studies revealed a gene that, when overexpressed, increased biomass and sugar yield in sorghum and delayed flowering. These findings have important implications for genetic enhancement of plants.