Liyi Zhang, Jianxia Xu, Yanqing Ding, Ning Cao, Xu Gao, Zhou Feng, Kuiying Li, Bing Cheng, Lengbo Zhou, Mingjian Ren, Yuezhi Tao & Guihua Zou

Theoretical and Applied Genetics April 2023; vol. 136, Article number: 77

Published 23 March 2023

Key message

Seventy-three QTL related to grain color and tannin content were identified in Chinese sorghum accessions, and a new recessive allelic variant of TAN2 gene was discovered.

Abstract

Sorghum is mainly used for brewing distilled liquors in China. Since grain tannins play an important role in liquor brewing, accurately understanding the relationship between grain color and tannin content can provide basis for selection standards of tannin sorghum. We resequenced a panel of 242 Chinese sorghum accessions and performed population structure and genome-wide association study (GWAS) to identify quantitative trait locus (QTL) affecting pericarp color, testa pigment, and tannin content. Phylogenetic analysis, principal component analysis (PCA), and admixture model were used to infer population structure. Two distinct genetic sub-populations were identified according to their corresponding northern and southern geographic origin. To investigate the genetic basis of natural variation in sorghum grain color, GWAS with 2,760,264 SNPs was conducted in four environments using multiple models (Blink, FarmCPU, GLM, and MLM). Seventy-three QTL were identified to be associated for the color of exocarp, mesocarp, testa, and tannin content on all chromosomes except chromosome 5, of which 47 might be novel QTL. Some important QTL were found to colocalize with orthologous genes in the flavonoid biosynthetic pathway from other plants, including orthologous of Arabidopsis (Arabidopsis thaliana) TT2, TT7, TT12, TT16 and AT5G41220 (GST), as well as orthologous of rice (Oryza sativa) MYB61 and OsbHLH025. Our investigation of the variation in grain color and tannin content in Chinese sorghum germplasm may help guide future sorghum breeding for liquor brewing.

See https://link.springer.com/article/10.1007/s00122-023-04307-z

Figure 6: Schematic genetic map of important QTL identified for exocarp color (EC), mesocarp color (EC), testa color (TC), and tannin content (TA). Genes detected in 1, 2, 3 and 4 environments are shown in black, blue, green and red colors, respectively, while those identified by more than 2 models (including 2 models) are followed by asterisk (color figure online).