背景回顾：High-quality radish (Raphanus sativus) genome represents a valuable resource for agronomical trait improvements and understanding genome evolution among Brassicaceae species. 

提出问题：However, existing radish genome assembly remains fragmentary, which greatly hampered functional genomics research and genome-assisted breeding. 

结果1-组装+注释：Here, using a NAU-LB radish inbred line, we generated a reference genome of 476.32 Mb with a scaffold N50 of 56.88Mb by incorporating Illumina, PacBio, and BioNano optical mapping techniques. Utilizing Hi-C data, 448.12 Mb (94.08%) of the assembled sequences were anchored to nine radish chromosomes with 40,306 protein-coding genes annotated. In total, 249.14 Mb (52.31%) comprised of repetitive sequences, among which long terminal repeats (LTRs, 30.30%) were the most abundant class. 

结果2-基因复制分析：Beyond confirming the whole-genome triplication (WGT) event in R. sativus lineage, we found several tandem arrayed genes were involved in stress response process, which may account for distinctive phenotype of high disease resistance in R. sativus. 

结果3-比较基因组分析：By comparing against the existing Xin-li-mei radish genome, a total of 2,108,577 SNPs, 8063 large insertions, 8054 deletions and 84 inversions were identified. 

结果4-抽薹时间控制：Interestingly, a 647-bp insertion in the promoter of RsVRN1 gene can be directly bound by the DOF transcription repressor RsCDF3, resulting into its low promoter activity and late-bolting phenotype of NAU-LB cultivar. Importantly, introgression of this 647-bp insertion allele, RsVRN1^In-536, into early-bolting genotype could contribute to delayed bolting time, indicating that it is a potential genetic resource for radish late-bolting breeding. 

结论：Together, this genome resource provides valuable information to facilitate comparative genomic analysis and accelerate genome-guided breeding and improvement in radish.

高质量萝卜基因组是农艺性状改良和十字花科物种基因组演化研究的珍贵资源。但是，目前已公布的萝卜基因组还是片段化的，这严重阻碍了功能基因组研究和基因组辅助育种。本文中，作者以萝卜NAU-LB自交系为材料，采用二代Illumina、三代PacBio以及Bionano光学图谱技术相结合的方法，报道了萝卜的高质量基因组组装，大小约为476.32Mb，scaffold N50大小为56.88 Mb。利用Hi-C数据，94.08%的组装能够被挂载到9条染色体上，注释出40306个蛋白编码基因。重复序列注释显示萝卜基因组的52.31%为重复序列，其中最丰富的LTR，占了30.30%。除了证实了萝卜这一支发生过全基因组三倍化事件外，作者鉴定到了几个串联排列的基因，这些基因主要参与了胁迫响应的相关过程，可能与萝卜较高的抗病性表型相关。另外，通过与现有的Xin-li-mei萝卜基因组比较，作者鉴定了2,108,577个SNPs、8063大片段插入、8054个删除以及84个倒位。有趣的是，作者在RsVRN1基因的启动子上鉴定到了一段647bp的插入，而这段插入序列能够被DOF转录抑制子RsCDF3直接结合，从而导致更低的启动子活性以及NAU-LB栽培种的抽薹时间变晚。重要的是，将这一647bp的插入序列RsVRN1In-536导入到抽薹早的基因型中，能够延迟抽薹时间，表明其是萝卜晚抽薹育种的潜在遗传资源。综上，本文所报道的萝卜高质量基因组为加速比较基因组研究以及基因组辅助育种和改良提供了珍贵的信息资源。

** 柳李旺 **