Novel allelic variations in Tannin1 and Tannin2 contribute to tannin absence in sorghum

Authors: ZHANG, WENBIN - Shandong Agricultural University; Benke, Ryan; ZHANG, XIAO - Shandong Agricultural University; ZHANG, HUAWEN - Shandong Agricultural University; ZHAO, CUNYUAN - Shandong Agricultural University; ZHAO, YU - Shandong Agricultural University; XU, YING - Shandong Agricultural University; WANG, HAILIAN - Shandong Agricultural University; LIU, SHUBING - Shandong Agricultural University; Li, Xianran; WU, YUYU - Shandong Agricultural University

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2024
Publication Date: 3/16/2024
Citation: Zhang, W., Benke, R.L., Zhang, X., Zhang, H., Zhao, C., Zhao, Y., Xu, Y., Wang, H., Liu, S., Li, X., Wu, Y. 2024. Novel allelic variations in Tannin1 and Tannin2 contribute to tannin absence in sorghum. Molecular Breeding. 44. Article 24. https://doi.org/10.1007/s11032-024-01463-y.
DOI: https://doi.org/10.1007/s11032-024-01463-y

Interpretive Summary: Sorghum is the only cereal crop has a large proportion of cultivars with condensed tannins in seeds, suggesting both tannin or non-tannin types had are beneficial and were under direct selections. The tannin presence was mainly controlled by two genes (Tannin 1 and Tannin 2). Previous studies identified a total of 6 lost-of-function alleles, three for each, contribute to non-tannin phenotype. By screening a large population mainly collected from Asia, this study further uncovered 3 new lost-of-function alleles. One allele, tan-2d, was predominantly observed in China, suggesting an independent origin in selecting non-tannin phenotype. To facilitate breeding on tannin trait, a set of KASP genotype assay was developed to efficiently screen these nine identified recessive alleles.

Technical Abstract: Sorghum is an important food crop commonly used for brewing, feed stock, and bioenergy. Certain genotypes of sorghum contain high concentration of condensed tannins in seeds, which protects grains from herbivore bird pests but also impair grain quality and digestibility, and limit grain applications. Previously, we identified two genes, Tannin1 and Tannin2, each with three recessive causal alleles regulate tannin absence in sorghum. In this study, via characterizing 421 sorghum accessions, we further identified three novel recessive alleles from these two genes. The tan1-d allele contains a 12-bp deletion at position 659 and the tan1-e allele contains a 10-bp deletion at position 771 in Tannin1. The tan2-d allele contains a C-to-T transition, which results in a premature stop codon before the bHLH domain in Tannin2, was predominantly selected in China. We further developed 9 KASP assays targeted these identified recessive alleles to efficiently genotype large population. These study provided new insights in sorghum domestication and convenient tool for breeding program.