Genetic analyses of anthocyanin content using polyploid GWAS followed by QTL detection in the sweetpotato (Ipomoea batatas L.) storage root

Abstract

: Genetic studies on the purple-fleshed sweetpotato ( Ipomoea batatas L.), which is rich in anthocyanin (AN) in the storage root, were performed by polyploid GWAS based on the allele dosage probability using 59,675 SNPs obtained from 94 F 1 progenies between the cultivars ‘Konaishin’ (which has a high yield but no AN) and ‘Akemurasaki’ (which has a high AN content but low to moderate yield). The distribution of relative AN content was highly biased, with 60% of clones showing a low to undetectable level (A 530 < 0.5). Fifty-nine SNPs from six signals on homologous groups (HGs) 3, 5 (one major and one smaller sig-nal), 7, 13, and 15 were strongly associated with the relative AN content. Twelve SNPs from the major signal and one from the smaller signal of HG 5 were further detected by QTL analysis. In a database search of the AN biosynthesis gene, transcription factors IbMYB1 and IbWD40 and AN structural genes IbF3H and IbDFR were located on HG 5, suggesting that an SNP marker or markers from HG 5 might be tightly linked to candidate gene(s) homologous to one of these transcription factors and AN structural genes as a major factor in determining AN accumulation in the storage roots. These results would enhance our understanding of the underlying genetic basis of AN accumulation in the storage roots of sweetpotatoes, and the SNP markers found here, especially 13 SNPs from HG 5, would be a potential platform for future marker-assisted selection for breeding high-AN sweetpotato varieties.