A rare dominant allele <i>DYSOC1</i> determines seed coat color and improves seed oil content in <i>Brassica napus</i>.

Abstract

Yellow seed coat color (SCC) is a valuable trait in <i>Brassica napus</i>, which is significantly correlated to high seed oil content (SOC) and low seed lignocellulose content (SLC). However, no dominant yellow SCC genes were identified in <i>B. napus</i>. In this study, a dominant yellow SCC <i>B. napus</i> N53-2 was verified, and then 58,981 eQTLs and 25 trans-eQTL hotspots were identified in a double haploid population derived from N53-2 and black SCC material Ken-C8. A rare dominant allele <i>DYSOC1</i> (<i>dominant gene of yellow seed coat color and improved seed oil content 1</i>) was subsequently cloned in a trans-eQTL hotspot that colocated with SCC, SOC, and SLC QTL hotspot on ChrA09 through QTL fine mapping and multi-omics analysis. Transgenic experiments revealed that the expression of <i>DYSOC1</i> produced yellow SCC seeds with significantly increased SOC and decreased SLC. Our result provides a rare dominant yellow SCC allele in <i>B. napus</i>, which has excellent potential for yellow SCC and high SOC rapeseed breeding.