Researchers analyzed sorghum grain development across genotypes and growing seasons, highlighting differences in grain filling, phenolic compound synthesis, and antioxidant capacity, with phenolic accumulation shifting from early-stage phenolic acids to flavonoid dominance in mature grains.

Keywords: Sorghum bicolor, UHPLC-MSE, antioxidant compounds, polyphenols

Sorghum grain development follows a distinct four-stage process, with rapid grain filling occurring between 10 and 25 days after flowering (DAF) and stabilization by 40DAF. Research by scientists from Federal University of the State of Rio de Janeiro and University Montpellier revealed that the Macia genotype maintained a consistent grain mass across different growing seasons (GS), while IS15752 exhibited variations, particularly a delayed but ultimately greater grain dry mass at 33DAF. This suggests differences in starch and protein accumulation timing between genotypes. Phenolic compound (PC) synthesis was tracked throughout grain development, with total PC content (TPC) increasing significantly from 10DAF to 25DAF and stabilizing thereafter. IS15752 consistently showed higher PC content than Macia, likely due to tannin presence. Additionally, bound phenolic compounds (BPC) contributed most to TPC increases, particularly in Macia GS1, aligning with prior findings in maize but differing from wheat, where free phenolics (FPC) dominate.

Comprehensive PC profiling using UHPLC-MSE identified 97 compounds, predominantly flavonoids (54%) and phenolic acids (32%), with a higher prevalence in free extracts, contrary to previous findings in cereals. The phenolic profile evolved over time, with phenolic acids dominating early (10–17DAF), followed by flavonoid predominance at maturity (33–40DAF). PCA and hierarchical clustering confirmed clear separations between developmental stages, supporting shifts in the phenylpropanoid biosynthetic pathway. High-tannin IS15752 had distinct phenolic accumulation patterns, reinforcing the influence of genotype on sorghum’s antioxidant properties. These findings underscore the importance of developmental timing in optimizing sorghum’s nutritional and functional benefits, particularly for food and health applications.

SorghumBase example: 

Figure 1: Homology analysis of Sorghum bicolor associated with tannin, a class of flavonoids. The identified genes, including SORBI_3002G186600, SORBI_3002G186700, SORBI_3002G168800, SORBI_3003G094350, SORBI_3003G094500, SORBI_3004G162700, and SORBI_3004G162800, show sequence similarity with homologs in other species. The closest annotated homologs from Oryza sativa, Arabidopsis thaliana, and other plants are displayed with percentage similarity values.
Figure 2: Quantitative Trait Loci (QTL) mapping of Loci associated with Tannin content. Each row represents a QTL with its genomic location, annotation source, and external references. The listed loci include Q7ANN1.1, Q7ANN1.4, Q7ANN1.6, and others, highlighting the genetic regions associated with important agronomic traits in sorghum in regard to phenolic content.

Reference:

D’almeida CTDS, Morel MH, Terrier N, Mameri H, Simões Larraz Ferreira M. Dynamic Metabolomic Changes in the Phenolic Compound Profile and Antioxidant Activity in Developmental Sorghum Grains. J Agric Food Chem. 2025 Jan 15;73(2):1725-1738. PMID: 39811928. doi: 10.1021/acs.jafc.4c08975. Read more

Related Project Websites: 

Developmental Dynamics of Phenolic Compounds and Antioxidant Capacity in Sorghum Grain Across Genotypes and Seasons

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