Petal size in rapeseed: novel QTL and candidate genes detected through genome-wide association study and transcriptome comparison

Petal size determines the value of ornamental plants, and thus their economic worth. However, the molecular mechanisms controlling petal size remain unclear in most non-model species. To identify quantitative trait loci and candidate genes regulating petal size in rapeseed (Brassica napus), we performed a genome-wide association study (GWAS) using data from 588 accessions over three consecutive years. We detected 17 significant single nucleotide polymorphisms (SNPs) associated with petal size, with the most significant SNPs located on chromosomes A05 and C06. A combination of GWAS and transcriptomic sequencing based on two accessions with extreme differences in petal size identified 11 differentially expressed genes (DEGs) that may control petal size variation in rapeseed. In particular, BnaA05.RAP2.2 homologous to RAP2.2 in rapeseed may be a critical gene negatively influencing petal size through the ethylene signaling pathway. In addition, a comparison of petal epidermal cells indicate...

花瓣大小是观赏植物观赏价值的核心决定因素，进而影响其经济价值。然而，在多数非模式植物中，调控花瓣大小的分子机制仍未明确。为鉴定调控甘蓝型油菜（Brassica napus）花瓣大小的数量性状位点（quantitative trait loci）与候选基因，本研究基于588份种质资源连续三年的表型数据开展了全基因组关联分析（genome-wide association study, GWAS）。本研究共检测到17个与花瓣大小显著关联的单核苷酸多态性（single nucleotide polymorphisms, SNPs），其中关联效应最强的SNPs位于A05和C06染色体上。结合对两份花瓣大小极端差异的种质开展的GWAS与转录组测序分析，本研究共筛选得到11个可能调控油菜花瓣大小变异的差异表达基因（differentially expressed genes, DEGs）。具体而言，与RAP2.2同源的BnaA05.RAP2.2可能是通过乙烯信号通路负向调控花瓣大小的关键基因。此外，对花瓣表皮细胞的比较分析显示……