Genetic discovery for oil production and quality in sesame.

Oilseed crops are used to produce vegetable oil. Sesame (Sesamum indicum), an oilseed crop grown worldwide, has high oil content and a small diploid genome, but the genetic basis of oil production and quality is unclear. Here we sequence 705 diverse sesame varieties to construct a haplotype map of the sesame genome and de novo assemble two representative varieties to identify sequence variations. We investigate 56 agronomic traits in four environments and identify 549 associated loci. Examination of the major loci identifies 46 candidate causative genes, including genes related to oil content, fatty acid biosynthesis and yield. Several of the candidate genes for oil content encode enzymes involved in oil metabolism. Two major genes associated with lignification and black pigmentation in the seed coat are also associated with large variation in oil content. These findings may inform breeding and improvement strategies for a broad range of oilseed crops.

The draft genome of the grass carp (Ctenopharyngodon idellus) provides insights into its evolution and vegetarian adaptation.

The grass carp is an important farmed fish, accounting for ∼16% of global freshwater aquaculture, and has a vegetarian diet. Here we report a 0.9-Gb draft genome of a gynogenetic female adult and a 1.07-Gb genome of a wild male adult. Genome annotation identified 27,263 protein-coding gene models in the female genome. A total of 114 scaffolds consisting of 573 Mb are anchored on 24 linkage groups. Divergence between grass carp and zebrafish is estimated to have occurred 49-54 million years ago. We identify a chromosome fusion in grass carp relative to zebrafish and report frequent crossovers between the grass carp X and Y chromosomes. We find that transcriptional activation of the mevalonate pathway and steroid biosynthesis in liver is associated with the grass carp's adaptation from a carnivorous to an herbivorous diet. We believe that the grass carp genome could serve as an initial platform for breeding better-quality fish using a genomic approach.