Rapeseed research and production in China

Rapeseed(Brassica napus L.) is the largest oilseed crop in China and accounts for about 20% of world production.For the last 10 years,the production,planting area,and yield of rapeseed have been stable,with improvement of seed quality and especially seed oil content.China is among the leading countries in rapeseed genomic research internationally,having jointly with other countries accomplished the whole genome sequencing of rapeseed and its two parental species,Brassica oleracea and Brassica rapa.Progress on functional genomics including the identification of QTL governing important agronomic traits such as yield,seed oil content,fertility regulation,disease and insect resistance,abiotic stress,nutrition use efficiency,and pod shattering resistance has been achieved.As a consequence,molecular markers have been developed and used in breeding programs.During 2005–2014,215 rapeseed varieties were registered nationally,including 210 winter-and 5 spring-type varieties.Mechanization across the whole process of rapeseed production was investigated and operating instructions for all relevant techniques were published.Modern techniques for rapeseed field management such as high-density planting,controlled-release fertilizer,and biocontrol of disease and pests combined with precision tools such as drones have been developed and are being adopted in China.With the application of advanced breeding and production technologies,in the near future,the oil yield and quality of rapeseed varieties will be greatly increased,and more varieties with desirable traits,especially early maturation,high yield,high resistance to biotic and abiotic stress,and suitability for mechanized harvesting will be developed.Application of modern technologies on the mechanized management of rapeseed will greatly increase grower profit.

Mutation of the PHYTOENE DESATURASE 3 gene causes yellowish-white petals in Brassica napus

Oilseed rape (Brassica napus) with yellow flowers is an attractive ornamental landscape plant during the flowering period,and the development of different petal colors has become a breeding objective.Although yellowish flower color is a common variant observed in field-grown oilseed rape,the genetics behind this variation remains unclear.We obtained a yellowish-white flower (ywf) mutant from Zhongshuang 9 (ZS9) by ethyl methanesulfonate mutagenesis (EMS) treatment.Compared with ZS9,ywf exhibited a lower carotenoid content with a reduced and defective chromoplast ultrastructure in the petals.Genetic analysis revealed that the yellowish-white trait was controlled by a single recessive gene.Using bulked-segregant analysis sequencing (BSA-seq) and kompetitive allele-specific PCR(KASP),we performed map-based cloning of the ywf locus on chromosome A08 and found that ywf harbored a C-to-T substitution in the coding region,resulting in a premature translation termination.YWF,encoding phytoene desaturase 3 (PDS3),was highly expressed in oilseed rape petals and involved in carotenoid biosynthesis.Pathway enrichment analysis of the transcriptome profiles from ZS9 and ywf indicated the carotenoid biosynthesis pathway to be highly enriched.Further analyses of differentially expressed genes and carotenoid components revealed that the truncated Bna A08.PDS3 resulted in decreased carotenoid biosynthesis in the mutant.These results contribute to an understanding of the carotenoid biosynthesis pathway and manipulation of flower-color variation in B.napus.

Chromosome-scale genome assembly-assisted identification of Brassica napus BnDCPA1 for improvement of plant architecture and yield heterosis

Plant architecture can act as a pivotal determinant of crop yield by maximizing photosynthate accumulation in grains,but no B.napus rapeseed ideotype has yet been defined.However,semi-dwarf and compact(SDC)rapeseed plant types with the capacity to maximize silique number per hectare and seed weight per silique are expected to optimize plant architecture for groundbreaking seed yield,avoiding lodging and promoting mechanical harvest(Liu et al.,2022).In this study,we report the mutant dc1,which exhibits DC plant architecture with significantly increased silique number in the main inflorescence compared with currently cultivated high and loose(HL)plant types like those of elite cultivars(Figure 1A and Supplemental Figure 1).

BnaOmics:A comprehensive platform combining pan-genome and multi-omics data from Brassica napus

Dear Editor,Brassica napus was originally formed7500 years ago by the interspecific hybridization of B.rapa and B.oleracea(Chalhoub et al.,2014).It accounts for approximately 13%–16%of global vegetable oil production and provides an excellent model for polyploid genomics and evolutionary research in plants.Currently,the Brassicaceae Database(BRAD V3.0;Chen et al.,2022),Genoscope(https://www.genoscope.cns.fr/brassicanapus/),and Ensembl Plants(https://plants.ensembl.org)are used for genomic research pertaining to B.napus.However,they only provide genome browsers for research into the B.napus cultivar Darmorbzh.The B.napus pan-genome information resource(BnPIR)also provides eight B.napus reference genomes(Song et al.,2021),gene information,and resequencing data.The B.napus variation information resource(BnVIR)provides information on genetic variation,including single-nucleotide polymorphisms(SNPs),insertions or deletions(INDELs),and structural variations(SVs)(Yang et al.,2022).