Genome sequencing of the important oilseed crop Sesamum indicum L

Sesame (Sesamum indicum L., 2n = 26), which belongs to the Sesamum genus of the Pedaliaceae family, is one of the oldest oilseed crops and is cultivated in tropical and subtropical regions of Asia, Africa and South America [1,2]. Its cultivation history can be traced back to between 5,000 and 5,500 years ago in the Harappa Valley of the Indian subcontinent [3]. The total area of sesame harvested in the world is currently 7.8 million hectares, and annual production is 3.84 million tons (2010, UN Food and Agriculture Organization data). Being one of the four main sesame-producing countries, China has contributed 15.2 to 32.5% of the total world sesame production over the past 10 years (2001 to 2010, UN Food and Agriculture Organization data). Sesame has one of the highest oil contents: decorticated seeds contain 45 to 63% oil [2]. The seed is also rich in protein, vitamins, including niacin, minerals and lignans, such as sesamolin and sesamin [4-7], and it is a popular food and medicine [8-13]. Sequencing and analysis of the sesame genome is essential if we are to elucidate the evolutionary origins and characteristics of the sesame species.Sesamum is the main genus in the family Pedaliaceae, which contains 17 genera and 80 species of annual and perennial herbs that are distributed in the Old World tropics and subtropics [14]. The taxonomy and cytogenetics of the Sesamum genus has been reviewed and debated for a long time [1,14-17], and many heterogeneous landraces present in various growing areas still need to be distinguished [1,18]. S. indicum is the sole cultivar in the Sesamum genus and evolved from wild populations [14,19]. However, the origin and evolution of cultivated sesame is still unclear and requires more detailed investigation [1,15]. Evidence suggests that sesame may have originated in either India or Africa [3,20-26]. Bedigian reported that sesame was derived from the Indian subcontinent (the western Indian peninsula and parts of Pakistan) thousands of