Wei Xu 1 , Di Wu 1 , Tianquan Yang 1 , Chao Sun 1 , Zaiqing Wang 1 , Bing Han 1 , Shibo Wu 1 , Anmin Yu 2 , Mark A. Chapman 3 , Sammy Muraguri 1 , Qing Tan 1 , Wenbo Wang 1 , Zhigui Bao 4 , Aizhong Liu , 2 , De-Zhu Li , 5
20 April 2021
Castor bean ( Ricinus communis L.) is an important oil crop, which belongs to the Euphorbiaceae family. The seed oil of castor bean is currently the only commercial source of ricinoleic acid that can be used for producing about 2000 industrial products. However, it remains largely unknown regarding the origin, domestication, and the genetic basis of key traits of castor bean.
Here we perform a de novo chromosome-level genome assembly of the wild progenitor of castor bean. By resequencing and analyzing 505 worldwide accessions, we reveal that the accessions from East Africa are the extant wild progenitors of castor bean, and the domestication occurs ~ 3200 years ago. We demonstrate that significant genetic differentiation between wild populations in Kenya and Ethiopia is associated with past climate fluctuation in the Turkana depression ~ 7000 years ago. This dramatic change in climate may have caused the genetic bottleneck in wild castor bean populations. By a genome-wide association study, combined with quantitative trait locus analysis, we identify important candidate genes associated with plant architecture and seed size.