Connecting Grain Flavonoid Composition to Human Health Effects.

Characterizing the genetic basis of natural variation of health-promoting compounds in staple crops and identifying their anti-inflammatory properties can help improve human nutrition through marker-assisted breeding. Dietary flavonoids act as anti-inflammatory compounds, and are correlated with lower incidence of cardiovascular disease, cancer, type II diabetes, and other chronic inflammatory diseases. Sorghum [Sorghum bicolor (L.) Moench], one of the world's major cereal crops, is a valuable resource for flavonoid diversity compared to most cereal crops. The goals of this study were to use quantitative natural variation of sorghum grain flavonoids to (1) identify single-nucleotide polymorphisms (SNPs) associated with high or low flavonoid concentrations using a genome-wide association study (GWAS) with 404,628 SNP markers, and (2) identify varieties with high anti-inflammatory properties using mouse macrophage cells. GWAS identified novel quantitative trait loci for sorghum flavonoids, some of which colocalized with homologs of flavonoid pathway genes from other crops.  Cell culture experiments identified sorghum varieties that attenuated inflammation, and found a potential mechanism responsible for its anti-inflammatory actions. This catalog of flavonoid pathway loci and survey of natural variation in sorghum anti-inflammatory properties may be useful to guide future enhancement of cereal polyphenols.